cereal processing - dl.otvet.gov.et

Cereal Processing

Level II

Based on October 2019, Version 2

Occupational standards

Module Title: Operating Milling and Purification

LG Code: IND CRP2 M09 LO (1-3) LG (24-26)

TTLM Code: IND CRP2 TTLM09 20 v1

October, 2020

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Author/Copyright TVET program title- Cereal processing

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Table of Contents

LO #1- Prepare the milling and purification equipment for process

operation.................................................................................................... 5

Instruction sheet ..................................................................................................... 5

Information Sheet 1- Confirming material and available stock ................................ 7

Self-check 1 ................................................................................................... 12

Information Sheet 2- Identification of cleaning, maintenance and service ............ 13

requirements ......................................................................................................... 13

Self-Check – 2 ................................................................................................ 21

Information Sheet 3- Defining operation equipment and process ......................... 22

Self-Check – 3 ................................................................................................ 27

Information sheet 4- Adjusting machine components and related attachments .... 28

Self-Check – 4 ................................................................................................ 36

Information sheet 5- Identification of processing and operating parameters ......... 37

Self-Check – 5 ................................................................................................ 42

Information sheet 6- Checking and adjusting equipment performance ................. 43

Self-Check – 6 ................................................................................................ 45

Information Sheet 7- Carrying out pre-start checks .............................................. 46

Self-Check – 7 ...................................................................................................... 48

Operation Sheet 1- Guidelines for correct grain storage ....................................... 49

Operation Sheet 2- Cleaning steps for excess zirconia dust avoidance ............... 50

Operation Sheet 3- Milling machine safe work procedure .................................... 51

Operation Sheet 4– Procedures of mounting feed grinding machine.................... 52

Operation Sheet 5 – Rice milling process ............................................................. 55

Operation Sheet 7 – Pre-operation of milling machine handling techniques ......... 56

LAP Test ........................................................................................................ 57

LG #25 ...................................................................................................... 59

LO #2-Operate and monitor the milling and purification process ......... 59

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Instruction sheet ................................................................................................... 59

Information Sheet 1- Workplace information, policies and procedures ................. 61

Self-Check – 1 ................................................................................................ 67

Information Sheet 2- Starting and operating the process ...................................... 68

Self-Check – 2 ................................................................................................ 72

Information Sheet -3 Monitoring equipment variation in operating conditions ....... 73

Self-Check – 3 ................................................................................................ 77

Information Sheet 4 - Identifying variation in equipment operation ....................... 78

Self-Check – 4 ............................................................................................... 81

Information Sheet 5 - Reporting maintenance as per workplace reporting format 81

Self-Check – 5 ................................................................................................ 85

Information Sheet 6 - Monitoring and confirming process specification ................ 86

Self-Check – 6 ................................................................................................ 87

Information Sheet -7 Removing fine bran from semolina and bran product .......... 88

Self-Check – 7 ................................................................................................ 92

Information Sheet 8 - Retuning fine bran product to purification or scratch rolls ... 93

Self-Check – 8 ................................................................................................ 97

Information Sheet 9 - Identifying, rectifying and reporting out-of-specification ...... 98

Product/process outcomes ................................................................................... 98

Self-Check – 9 .............................................................................................. 101

Information Sheet 10 - Maintaining the work area with housekeeping standards 102

Self-Check – 10 ........................................................................................... 105

Information Sheet 11 - Conducting work with environmental standards and ...... 106

legislative requirements ...................................................................................... 106

Self-Check – 11 ............................................................................................ 110

Information Sheet 12 - Maintaining workplace records requirements ................. 111

Self-Check – 12 ........................................................................................... 113

Operation Sheet 1- procedure for grinding the bore of a bushing ....................... 114

Operation Sheet 2- Steps of using cleaning hose and wet cleaning process. .... 115

Operation Sheet 3- Reduction means of dust emissions .................................... 116

LAP Test ...................................................................................................... 116

Demonstration ............................................................................................ 116

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LO #3- Shut down the milling and purification process ...................... 117

Instruction sheet ................................................................................................. 117

Information Sheet 1- Identify shutdown procedures............................................ 118

Self-Check – 12 ........................................................................................... 121

Information Sheet 2- Shut down process with workplace procedures................. 122

Self-Check – 2 ............................................................................................. 125

Information Sheet 3- Identifying and reporting maintenance requirements ......... 127

Self-Check – 3 .............................................................................................. 132

Reference Materials ..................................................................................... 135

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LG #24 LO #1- Prepare the milling and purification equipment for

process operation

Instruction sheet

This learning guide is developed to provide you the necessary information regarding the

following content coverage and topics:

Confirming material and available stock,

Identification of cleaning, maintenance and service requirements,

Defining operation equipment and process,

Adjusting machine components and related attachments,

Identification of processing/operating parameters,

Checking and adjusting equipment performance, and

Carrying out pre-start checks.

This guide will also assist you to attain the learning outcomes stated in the cover page.

Specifically, upon completion of this learning guide, you will be able to:

Confirm material and available stock,

Identify cleaning, maintenance and service requirements,

Define operation equipment and process,

Adjust machine components and related attachments,

Identify of processing/operating parameters,

Check and adjust equipment performance, and

Carry out pre-start checks.

Learning Instructions:

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1. Read the specific objectives of this Learning Guide.

2. Follow the instructions described below.

3. Read the information written in the information Sheets

4. Accomplish the Self-checks

5. Perform Operation Sheets

6. Do the “LAP test”

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Information Sheet 1- Confirming material and available stock

1.1 Introduction

Raw materials (ingredients, processing aids, and packaging materials) are the

foundation of finished food products. As such, they must meet regulatory requirements

(safe and legal for your intended use) and your specifications (contribute to the

functionality and quality of your process and product).

1.2 Definitions

The meaning of material requirements planning (MRP): a system for

calculating materials and components needed to manufacture a product.

Introduction materials requirements planning: referred to by the initials MRP,

is a technique which assists a company in the detailed planning of its production.

Recall here that the master production schedule sets out an aggregate plan for

production. MRP translates that aggregate plan into an extremely detailed plan.

Data integrity requirements: MRP is highly dependent on having accurate

information about key inputs, especially demand, inventory and production. If

one or two inputs are inaccurate, errors can be magnified at later stages. Data

integrity and data management are thus essential to effective use of MRP

systems.

The material availability data: The MRP element related data, the required/

requested quantity, the confirmed quantity, the cumulated ATP quantity (quantity

still available after the confirmation is made).

Thus, the importance of raw materials is obvious to those stakeholders that operate

upstream (Figure 1) extracting, refining, and processing material into products; such

stakeholders are intimately aware of the vagaries of material supply and prices.

However, it is critical that all stakeholders become aware of the potential impact of raw

material supplies on their business. In light of this, supply chain stakeholders, should be

aware of the stresses that supply chains place on materials use and the vulnerability of

the supply base for that material to change.

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Cereal processing offers good opportunities for small-scale businesses in Ethiopia

because raw materials are readily available, most equipment is reasonably affordable

and if the products are chosen correctly, they have a good demand and can be

profitable. However, small-scale cereal processors are confronted with strong

competition in the domestic and regional markets. To be profitable it is essential to have

high quality products, an attractive package where appropriate and a well-managed

business.

Figure 1: Supply chain diagram from upstream raw material manufacturer to downstream retail

and reverse supply chain which includes disposal and recycling.

1.3 Quality of raw materials

Poor quality grain is one of the most common problems facing millers and is caused by

inadequate post-harvest control by farmers and inadequate storage conditions in the

mill. Most millers buy their grain from farmers and have little control over the way in

which grain is grown, harvested, stored or transported. Contract agreements with

farmers can improve the amount of control that millers have over the quality of raw

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materials. Contracts with farmers Quality assurance in contract growing covers the

following areas:

Correct application of chemicals during cultivation

Harvest at the correct stage of maturity

Correct threshing and winnowing

Adequate drying and post-harvest storage

Correct packaging and transport of grains. Contamination by pesticides and chemical

fertilizers can be due to inadequate information or training for farmers in the amounts of

chemicals to use, or the timing of their application. As part of contract agreements,

millers can prevent such problems by supervising chemical use and checking that

chemical applications are in line with manufacturers’ recommendations. The use of

agricultural chemicals is controlled by law in Ethiopia and millers should check with the

Ministry of Agriculture, Animal Industries and Forestry and the Ethiopian National

Bureau of Standards for details of the specific laws. Millers can also specify or

supervise harvesting to ensure that this is done at the correct stage of maturity and

minimize contamination. Correct post-harvest storage is needed to minimize the risk of

mould growth on grains. Moulds give an unpleasant smell to flour that makes it

unacceptable to consumers and may also damage their health. Some species of

moulds produce poisons in cereals, known as ‘aflatoxins’. These have no taste and may

be eaten by consumers, with the risk of long-term damage to the liver, digestive system

and kidneys.

1.2.1 Guidelines for correct grain storage

Make sure the storeroom is waterproof by locating it on well drained land,

raising it above the ground and fitting a waterproof roof

Prevent the temperature in the store from fluctuating by using insulating

materials (brick, mud, clay, wood or other insulation), painting the outside

white and fitting an overhanging roof to keep sunlight off the walls.

Ensure that the store is insect-proof, rat-proof and bird-proof

Thoroughly clean storerooms by removing and burning all old grain, straw,

insects etc. to prevent contamination of new grain

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Make sure that grain is properly dried before putting it into a store

If chemical insecticides or fungicides are used, ensure that manufacturer’s

recommended dosages are followed.

Regularly check the grain for infestation, signs of mould or discolouration

and ensure that it is not getting hot (each is a sign of excessive moisture).

If these are found, remove the grain and re-dry it.

Most grain is transported in sacks, but the quality of re-used sacks is often not checked.

Dirty sacks contaminate grain and inadequately sealed sacks allow birds, insects and

rodents to contaminate the grain. Control over transport to the mill is part of a quality

assurance scheme and millers should supply good quality sacks for collecting grain and

preferably arrange transport to collect grain directly from the farmers using their own

vehicles, or contracted haulers’ vehicles that have been inspected to ensure that they

are clean. When sacks arrive at the mill, they should be checked to ensure that there

are no holes in the sacks or loose sewing at the top. Sacks should be dry and clean and

not obviously contaminated by oil, grease, kerosene etc. Grain may contain field

contaminants (weed seeds, stalks, soil, stones and dead or living insects), as well as

metal or wood fragments, diesel, oil, etc. from transportation. When the sacks are

opened at the mill, the grain should be spread onto an inspection table checked visually

for:

Contamination by foreign materials

Damage or contamination caused by insects, birds and rodents

Excessive moisture content or mould growth

Broken or immature grains

Foreign materials, mouldy or discoloured grains should be removed by

hand. Some millers also wash grain in a tank to remove sand, small

stones or dust.

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Self-check 1 0Written test

Name…………………………………………… ID………………………… Date…….

Directions: Answer all the questions listed below. Examples may be necessary to aid

some explanations/answers.

Test I: Choose the best answer (4 point)

1. Contracts with farmers Quality assurance in contract growing covers the following

areas:

A. Correct application of chemicals during cultivation.

B. Harvest at the correct stage of maturity.

C. Correct threshing and winnowing & adequate drying and post-harvest

storage.

D. All .

2. Which one of the following guidelines is not appropriate for correct grain storage?

A. storeroom is shall be waterproof.

B. Properly dried grain needed.

C. Temperature fluctuation is required.

D. Regular checking for infestation.

Test II: Short Answer Questions

1. What does material requirements planning mean? (3points)

2. What is introduction Materials Requirements Planning? (3points)

3. What are the requirements for material requirement planning? (3points)

4. What is material availability date? (3 points)

5. Discuss on supply chain diagram from upstream raw material manufacturer to. (5

points)

6. _________________ referred to by the initials material requirement planning, which

is a technique which assists a company in the detailed planning of its production. (2

points)

You can ask you teacher for the copy of the correct answers

Note: Satisfactory rating - 10 points Unsatisfactory - below 10 points

You can ask you teacher for the copy of the correct answers.

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Information Sheet 2- Identification of cleaning, maintenance and service

requirements

2.1 Building inspection and routine cleaning programmes

Flour dust accumulations attract insects and rodents, which in turn contaminate the

products. It is therefore essential that a monthly inspection be made of floors and walls

for cracks and to ensure that windows and ceiling panels are intact and in place. This

should be part of the job description for a member of staff, who should tick off each

check against a written checklist. The mill owner or manager should ensure that the

checks are properly done.

All spilled grain and flour should be cleaned up at the end of each day’s production

to prevent flour mites and other insects from breeding and contaminating the products.

If infestation is found it should be treated by spot-spraying, but this indicates a failure in

a cleaning programme and changes should be introduced to improve cleaning. Brightly

coloured brooms, brushes and cloths should be used so that any bristles or cloth

fragments to be easily seen if they contaminate the flour.

Fumigants can be used to disinfest grain stores and the following are approved in

Ethiopia: lindane, bromophos, Malathion, dichlorvos, piperonyl butoxide, pyrethrum or

combinations of these. Manufacturer's instructions must be strictly observed and made

available to operators in their language. Methyl bromide gas is now being phased out

under the Montreal Protocol because it destroys the ozone layer.

Process control seed cleaners, dehullers and mills should be checked daily for

loose nuts or bolts and to ensure that settings are correct. Parts that are likely to

wear out should be checked monthly as part of a planned maintenance programme.

Contaminants such as metal fragments, pieces of hardened flour, wire or nylon from

sieves or cotton fibres from sacks can each contaminate flour during milling. Sieves

should be used at points throughout the process to collect larger contaminants and

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checked regularly. Contaminants should be recorded and any sudden increase, which

indicates that a problem has arisen, should be investigated and corrective action taken.

Magnets remove any ferrous (iron and steel) metal fragments from grain or flour.

Permanent magnets are preferred because electromagnets can drop an accumulated

mass of filings into the flour if the power fails. Magnets cannot pick up nonferrous

metals and these must be checked for by visual inspection.

Seed cleaners/Winnowers

At its simplest, a seed cleaner is a mesh table on which grain can be spread out and

examined. Dust and small stones fall through the holes in the table and larger leaves,

stalks, mouldy grains etc. can be picked out. Mechanized cleaners consist of an inclined

vibrating flat screen (Figure 1). Grain is fed onto the screen and the vibration assists in

separating the contaminants. These machines cause considerable dust and should be

located in an area where dust can be prevented from contaminating other equipment or

products. They should be cleaned daily by brushing out dust and contaminants. When it

is necessary to wash grain to remove dust and other contaminants, this is done using a

trough or tank containing clean water and fitted with a drain tap so that water can be

regularly replaced. Iron fragments are removed from the grain using permanent

magnets, (electromagnets are not recommended because of the risk of power failures,

which would cause the magnet to drop the collected iron filings into the grain). Other

types of metal particles must be removed by hand on the inspection table.

Figure1. Here next also an example of diagrammatical cereal mill cleaning methods:

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Water system

Change the water at least once a week or when prompted by the system after 240

minutes wet machining time.

Add 75ml Dentate to the tank

Fill the tank with water until the filter(s) is/are completely immersed (up to the

bottom edge of the cover thread, approx. 3 liters)

Clean the filter(s) when changing the water or when the “water pressure too low

“message appears. Remove the filter(s) from tank and hold under warm water while

washing out material. Change the filter(s) immediately if damaged; otherwise every 3

months or after 3-4 filter cleanings. Clean the cooling water jets if they do not strike the

machining instruments by carefully removing any foreign particles from the water

nozzles with a cleaning wire or probe. This will help to extend the life of the instruments.

Changing the Filter Bag (CEREC Suction Device)

If there is a significant fall in suction power when dry milling zirconia, the filter bag (REF

65 78 095) could be full and will need replacing. Typically a filter bag should offer

capacity for ca. 120 restoration units. This number can vary depending on the amount of

zirconia material milled and extracted. To change the filter bag:

Loosen and remove the two knurled nuts on the maintenance cover.

Remove the cover.

Remove the full bag from the nozzle and replace with a new one.

Place the cover back on and screw tighten the two knurled nuts.

Note: ensure that the cap is sealed properly and the filter bag is not jammed.

Using the Cleaning Hose and Wet Cleaning Process

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The milling chambers of units used for dry milling zirconia should be regularly cleaned

to avoid a build-up of excess zirconia dust. A cleaning hose with nozzle can be used for

this. This hose is ordered separately as a spare part (REF 65 89 795).

2.2 Equipment maintenance

Another reason for lost production is delays caused by waiting for spare parts after

equipment breaks down. As a minimum, cereal processors should monitor the state of

equipment that is likely to wear out and as their experience grows over the years, they

should buy spare parts or send the machine for servicing when they expect that a

component is due to be replaced. There are likely to be a few parts that wear out more

quickly than others (e.g. mixer bearings, heating elements in bag sealers, drive belts

and hammers in mills). These should be identified and spare parts kept in stock.

Processors can make an agreement in advance, possibly involving a small annual fee,

to ensure that electricians or mechanics repair equipment as a priority. Lack of

maintenance is one of the most common problems that cause small-scale millers and

bakers to lose money. Machine breakdowns arise from a number of different causes.

They reduce productivity and increase production costs. Poorly maintained machines

also produce substandard products and can contaminate products with metal

fragments, as well as being a potential hazard to operators. Another common cause of

failure is when those who operate or maintain a machine arbitrarily alter it. Proper

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maintenance ensures that machinery operates correctly and safely and prolongs its life,

thus reducing capital and operating expenditure. To put preventive maintenance into

practice, the following actions are needed:

Identify priority machinery which has components that wear out more frequently.

Make a clear description of the procedures and standards for the work of

machine operators and maintenance workers (such as lubricating, tightening

bolts, adjustments etc.) in daily, weekly, monthly and yearly routine maintenance

plans as follows:

Before every wet machining process

o Ensure that the water and Dentatec solution completely covers

the filter(s) in the water tank

Weekly

o Change water in water tank and add 75ml Dentatec

Monthly

o Clean water filter monthly or as needed depending on usage

(change filter every 3-4 cleanings)

o Check and clean water jets to ensure that water is striking

the tools during wet machining

o Clean manual block clamp inside of the block axle

o Clean motor clamping cones for instruments without chuck

Yearly

o Annual maintenance carried out by a Service Technician

Dry milling zirconia only: Every 10 dry milled zirconia restorations

o Vacuum chamber and run wet cleaning program

Every 120 dry milled zirconia restorations

o Change filter bag (change HEPA filter every 3-4 filter bags)

Organize a schedule and train staff to implement maintenance plans.

Prepare a maintenance budget.

Record inspection results, analyze the records and evaluate the success of

maintenance.

Continuously update procedures and standards.

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NB: It is important to remove flour dust from equipment daily. A build-up of dust causes

rust to develop and on electrical equipment it causes moving parts to jam. It can also

seal the greasing points on machines and cause motors and engines to overheat and

burn out or seize.

2.3 Lighting, and power services

2.3.1 Lighting and power

Where lighting is needed, florescent tubes use less electricity than bulbs, but care is

needed when using fluorescent lights above mills, dehullers and other equipment that

has moving or rotating parts. This is because they can make machinery appear

stationary at certain speeds, causing a hazard to operators. Electricity is preferred for

bakery ovens because it is clean, flexible and easily controlled. Electric motors should

be fitted with isolators and starters. Plugs should be fitted with fuses that suit the power

rating of the equipment and the main supply should have an earth-leakage trip switch.

All electric wiring should be of the correct type for the intended purpose and installed by

a qualified and competent electrician. Where a three-phase (440 volt) supply is used in

larger mills, the load should be equally spread over the three phases. Multiple sockets

should not be used because they risk overloading a circuit and causing a fire. Cables

should be properly fixed to walls or run vertically from the ceiling to machines. There

should be no exposed wires at any connection.

2.3.2 Water supply and sanitation

Water is used in bakeries to make dough and for washing equipment. An adequate

supply of potable (safe for drinking) water should be available from taps in the

processing room. There are two potential problems with the water quality: sand and

contaminating microorganisms. Water from boreholes is likely to be relatively free from

micro-organisms, but may be contaminated with sand. River water is likely to be

contaminated with microorganisms and should only be used if no other source is

available. Samples of water should be periodically checked (e.g. once per year) for

microbial contamination at the Ethiopian laboratory, Department of Food Science and

Technology, Addis Ababa, or one of the commercial testing laboratories in Addis Ababa.

Because the amounts of water used in mills and bakeries are relatively small, any

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sediment can be removed by filtering. If micro-organisms are likely to contaminate the

water, they can be removed by water filters, by boiling water for 10-15 minutes, or by

dosing water with bleach (water for cleaning should be dosed by mixing 1 liter of bleach

into 250 liters’ of water. Water that is used as an ingredient has 2.5 ml of bleach to 250

liters of water). Care is needed when using bleach because it damages the skin and

particularly the eyes and can cause breathing difficulties if inhaled. It also corrodes

aluminium equipment.

Good sanitation is essential to prevent contamination of raw materials and processed

products by pests. Milling and bakery equipment should be thoroughly cleaned after

each day’s production, using a cleaning schedule that is clearly understood and

followed by production workers. Insects and rodents are attracted to food that is left

lying around and wastes should be removed each day and flour dust cleaned up.

Wastes should not be left in a processing room overnight. Hulls and bran should be

considered as by-products rather than wastes and sold to animal/poultry farmers or for

use in alternative products. Bulk stores of flour should be protected in a pest-proof

storeroom and small amounts of ingredients should be stored in insect- and rodent-

proof containers. Rodent traps are useful (but not poison) and if affordable, electric

‘insectocuters’ should also be used.

2.3.3 Fuels

Diesel is the preferred fuel for mills/dehullers etc., where electricity is not available. In

bakeries, fuel is one of the main costs if electric ovens are not used and the choice of

fuel is one off the main factors that determines the profitability of a business. Different

fuels have advantages and limitations in terms of cost, safety, risk of contamination of

products, flexibility of use and capital and operating costs of the oven. The cheapest

fuel is not always the most economical and it is necessary to carefully select the best

fuel to use in a bakery. Traditionally, wood has been cheap or free in Ethiopia and so

widely used in bakery ovens. However, deforestation in some areas has resulted in

increased cost of wood and legal restrictions on tree felling. It also produces a light fluffy

ash that can easily contaminate products. Charcoal is more expensive than wood, but it

produces a more intense heat with little smoke and a more compact ash. Bottled gas

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(LPG) is available in large urban centres and as fuel prices are constantly changing, this

may be cheap enough to compete with solid fuels. Other liquid fuels, such as kerosene

or diesel are not widely used because of the special burners required and the risk of

contaminating the product with off-odours. Petrol burners should not be used under any

circumstances because of the risk of an explosion.

2.3.4 Energy conservation

Bakeries and mills use large amounts of energy and their profitability depends partly on

reducing energy consumption. This can be done by only switching on mills, dehullers

etc. when they are needed, or by baking a sequence of different products as ovens

cool, to use all the available heat. Switching off lights in storerooms, or reducing vehicle

fuel consumption by coordinating product deliveries with collection of ingredients or raw

14 materials can make other savings. Other ideas include solar water heating (e.g. for

washing equipment), the use of fuel briquettes made from bran rather than fuel-wood

and using local suppliers of raw materials that can be delivered by bicycle, rather than

using a vehicle to collect them. When everyone does this, it can result in national

environmental and economic benefits by reducing deforestation and importation of

fuels.

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Self-Check – 2 Written test

Name…………………………………………… ID………………………… Date…….



Test I: Short Answer Questions

1. Write down why milling house require cleaning, maintenance and services

2. Indicate the clear description of the procedures and standards for the work of

machine operators and maintenance workers (such as lubricating, tightening bolts,

adjustments etc.) in daily, weekly, monthly and yearly routine maintenance plans



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Information Sheet 3- Defining operation equipment and process

3.1 Introduction

For efficient production and high productivity, the capacity of each piece of equipment in

a process should match the others. This prevents money being wasted on equipment

that is larger than necessary, or creating ‘bottlenecks’ caused by one piece of

equipment that is too small. For example, the output of a seed cleaner should match

that of the dehullers and the maize mill. The equipment that is required in a small flour

mill is shown in Table 1.

3.2 Milling equipment operational process

Table1. Equipment for milling

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The main items are seed cleaner, dehullers, a mill and packaging equipment and

these are described in simplified milling process diagram below (Figure 1).

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Figure1. Simplified milling process diagram

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The design and construction of feed hoppers, dehullers, mills and other equipment

should allow free passage of grains or flour without any recesses that could trap food

and lead to contamination. Careful design and construction also prevent the release of

dust from equipment. Most milling equipment is made from mild steel and it is important

that welding is done to a high standard, without holes in the weld or small projections

that could trap food. All welds should be ground to a smooth finish. Mild steel easily

rusts and it is important that equipment is kept dry to prevent rust from contaminating

the grain or flour. A mill or dehullers should be easy to dismantle for cleaning and

maintenance. Nuts and bolts that are routinely removed should be made from high

quality steel so that threads do not wear out quickly. Worn bolts have the potential to fail

and damage a mill or dehullers and injure an operator and metal fragments contaminate

the flour. Wherever possible, it is better to buy equipment from local suppliers or

engineering workshops because it should be faster and easier to have machines

serviced or to obtain spare parts. If equipment must be imported, the following points

should be considered when ordering it:

Say exactly what is required (manufacturers may have a range of similar

machines).

Give the throughput required in kg or liters per hour and the type of food to be

processed.

Where possible, give other information (model number of machine, single or

three-phase power, number and types of spare parts required).

3.3 Safe Work Procedure Checklist

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Table 2. Milling machine pre-operation, operation and post-operation procedure

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Name…………………………………………… ID………………………… Date…….




1. List down at least five equipment that is required in a small flour mill.

2. Draw the simplified flow diagram of mill by sequence and variation of operation.




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Information sheet 4- Adjusting machine components and related attachments

4.1 Introduction

Grain mill machine is mainly consist of feed hopper, milling body, drive motor, frame

etc. The body and rotor assembly together form the crushing chamber, rotor assembly

roomis the main working parts, materials of shattered in the crushing chamber

complete. When the material entered into the crushing chamber, by the round and flat

part of the tooth gear fault strike and knead into effect, broken materials into a fine

powder quickly and plasma shape, then air flow in the centrifugal force function, grinded

materials through the sieve get into discharge hole discharge of corn milling machine.

The attachment is standard or special auxiliary devices intended to be fastened to or

joined with one or more components of the milling machine. These devices increase the

capability of milling machine. One machine can perform number of operation by using

various types of attachments. Moreover, an efficient and positive method of holding

workplaces to the milling machine table is important if the machine tool is to be used to

its fullest advantage. The most common methods of holding are clamping a workpiece

to the table, clamping a workpiece to the angle plate, clamping the workpiece in fixtures,

holding a workpiece between centers, holding the workpiece in a chuck, and holding the

workpiece in a vise.

4.2 Methods of mounting workpieces

4.2.1 Clamping Workpieces to the Table

When clamping a workpiece to the worktable of the milling machine, the table and

the workpiece should be free from dirt and burrs. Workpieces having smooth

machined surfaces may be camped directly to the table, provided the cutter does not

come in contact with the table surface during milling. When clamping workplaces

with unfinished surfaces in this way, the table face should be protected from damage

by using a shim under the workpiece. Paper, plywood, and sheet metal are shim

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materials. Clamps should be located on both sides of the workpiece if possible to

give a full bearing surface. These clamps are held by T-slotbolts inserted in the T-

slots of the table. Clamp supports must be the same height as the workpiece. Never

use clamp supports that are lower than the workpiece. Adjustable step blocks are

extremely useful to raise the clamps, as the height of the clamp bar may be adjusted

to ensure maximum clamping pressure. Clamping bolts should be placed as near to

the workpiece as possible so that the full advantage of the fulcrum principle may be

obtained. When it is necessary to place a clamp on an overhanging part, a support

should be provided between the overhang and the table to prevent springing or

possible breakage. A stop should be placed at the end of the workpiece where it will

receive the thrust of the cutter when heavy cuts are being taken.

4.2.2 Clamping a workpiece to the angle plate

Workpieces clamped to the angle plate may be machined with surfaces parallel,

perpendicular, or at an angle to a given surface. When using this method of holding

a workpiece, precautions should be taken similar to those mentioned for clamping

work directly to the table. Angle plates are either adjustable or nonadjustable and

are generally held in alignment by keys or tongues that fit into the table T-slots.

4.2.3 Clamping workpieces in fixtures

Fixtures are generally used in production work where a number of identical pieces

are to be machined. The design of the fixture depends upon the shape of the piece

and the operations to be performed. Fixtures are always constructed to secure

maximum clamping surfaces and are built to use a minimum number of clamps or

bolts in order to reduce the setup time required. Fixtures should always be provided

with keys to assure positive alignment with the table T-slots.

4.2.4 Holding workpieces between centers

The indexing fixture is used to support workpieces which are centered on both

ends. When the piece has been previously reamed or bored, it may be pressed upon

a mandrel and then mounted between the centers. Two types of mandrels may be

used for mounting workpieces between centers. The solid mandrel is satisfactory for

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many operations, while one having a shank tapered to fit into the index head spindle

is preferred in certain cases. A jackscrew is used to prevent springing of long

slender workpieces held between centers or workpieces that extend some distance

from the chuck. Workpieces mounted between centers are fixed to the index head

spindle by means of a lathe dog. The bent tail of the dog should be fastened

between the setscrews provided in the driving center clamp in such a manner as to

avoid backlash and prevent springing the mandrel. When milling certain types of

workpieces, a milling machine dog is held in a flexible ball joint which eliminates

shake or spring of the dog or the workpiece. The flexible ball joint allows the tail of

the dog to move in a radius along the axis of the workpiece, making it particularly

useful in the rapid milling of tapers.

4.2.5 Holding workpieces in a chuck

Before screwing the chuck to the index head spindle, it should be cleaned and any

burrs on the spindle or chuck removed. Burrs may be removed with a smooth-cut,

three cornered file or scraper, while cleaning should be accomplished with a piece of

spring steel wire bent and formed to fit the angle of the threads. The chuck should

not be tightened on the spindle so tightly that a wrench or bar is required to remove

it. Cylindrical workpieces held in the universal chuck may be checked for trueness by

using a test indicator mounted upon a base resting upon the milling machine table.

The indicator point should contact the circumference of small diameter workpieces,

or the circumference and exposed face of large diameter pieces. While checking, the

workpiece should be revolved by rotating the index head spindle.

4.2.6 Holding Workpieces in the Vise

As previously mentioned, five types of vises are manufactured in various sizes for

holding milling machine workpieces. These vises have locating keys or tongues on

the underside of their bases so they may be located correctly in relation to the T-

slots on the milling machine table (Figure 1).

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Figure 1. Locating key and vises

The plain vise similar to the machine table vise is fastened to the milling machine

table. Alignment with the milling machine table is provided by two slots at right

angles to each other on the underside of the vise. These slots are fitted with

removable keys that align the vise with the table T-slots either parallel to the

machine arbor or perpendicular to the arbor. The swivel vise can be rotated and

contains a scale graduated in degrees at its base which is fastened to the milling

machine table and located by means of keys placed in the Tslots. By loosening the

bolts which clamp the vise to its graduated base, the vise may be moved to hold the

workpiece at any angle in a horizontal plane. To set a swivel vise accurately with the

machine spindle, a test indicator should be clamped to the machine arbor and a

check made to determine the setting by moving either the transverse or the

longitudinal feeds, depending upon the position of the vise jaws. Any deviation as

shown by the test indicator should be corrected by swiveling the vise on its base.

The universal vise is used for work involving compound angles, either horizontally or

vertically. The base of the vise contains a scale graduated in degrees and can rotate

360° in the horizontal plane and 90° in the vertical plane. Due to the flexibility of this

vise, it is not adaptable for heavy milling. The all-steel vise is the strongest setup

where the workpiece is clamped close to the table. This vise can securely fasten

castings, forgings, and rough-surface workpieces. The jaws can be positioned in any

notch on the two bars to accommodate different shapes and sizes. The air or

hydraulically operated vise is used more often in production work. This type of vise

eliminates the tightening by striking the crank with a lead hammer or other soft face

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hammer. When rough or unfinished workpieces are to be vise mounted, a piece of

protecting material should be placed between the vise and the workpiece to

eliminate marring by the vise jaws. When it is necessary to position a workpiece

above the vise jaws, parallels of the same size and of the proper height should be

used. These parallels should only be high enough to allow the required cut, as

excessive raising reduces the holding ability of the jaws. When holding a workpiece

on parallels, a soft hammer should be used to tap the top surface of the piece after

the vise jaws have been tightened. This tapping should be continued until the

parallels cannot be moved by hand. After the workpiece is set, additional tightening

of the vise should not be attempted, as such tightening has a tendency to raise the

work off the parallels. Correct selection of parallels is illustrated in Figure 2.

Figure 2. Mounting in the Vise workpiece

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Whenever possible, the workpiece should be clamped in the center of the vise jaws.

However, when necessary to mill a short workpiece which must be held at the end of

the vise, a spacing block of the same thickness as the piece should be placed at the

opposite end of the jaws. This will avoid strain on the movable jaw and prevent the

piece from slipping. If the workpiece is so thin that it is impossible to let it extend over

the top of the vise, holds down straps are generally used (Figure 3). These straps are

hardened pieces of steel, having one vertical side tapered to form an angle of about 92°

with the bottom side and the other vertical side tapered to a narrow edge. By means of

these tapered surfaces, the workpiece is forced downward into the parallels, holding

them firmly and leaving the top of the workpiece fully exposed to the milling cutter.

Figure 3. Application of hold-down strap

4.2.7 Indexing

Indexing is the process of evenly dividing the circumference of a circular workpiece into

equally spaced divisions, such as in cutting gear teeth, cutting splines, milling grooves

in reamers and taps, and spacing holes on a circle. The index head of the indexing

fixture is used for this purpose.

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4.2.7.1 Index Head

The index head of the indexing fixture (4) contains an indexing mechanism which is

used to control the rotation of the index head spindle to space or divide a workpiece

accurately. A simple indexing mechanism consists of a 40-tooth worm wheel fastened to

the index head spindle, a single-cut worm, a crank for turning the wormshaft, and an

index plate and sector. Since there are 40 teeth in the worm wheel, one turn of the

index crank causes the worm, and consequently, the index head spindle to make 1/40

of a turn; so 40 turns of the index crank revolve the spindle one full turn.

Figure 4. Indexing fixture

4.2.7.2 Index Plate

The indexing plate (Figure 5) is a round plate with a series of six or more circles of

equally spaced holes; the index pin on the crank can be inserted in any hole in any

circle. With the interchangeable plates regularly furnished with most index heads, the

spacing necessary for most gears, bolt heads, milling cutters, splines, and so forth can

be obtained. The following sets of plates are standard equipment: Brown and Sharpe

type consists of 3 plates of 6 circles each drilled as follows:

Plate I - 15, 16, 17, 18, 19, 20 holes

Plate 2 - 21, 23, 27, 29, 31, 33 holes

Plate 3 - 37, 39, 41, 43, 47, 49 holes

Cincinnati type consists of one plate drilled on both sides with circles divided as follows:

First side - 24, 25, 28, 30, 34, 37, 38, 39, 41, 42, 43 holes

Second side - 46, 47, 49, 51, 53, 54, 57, 58, 59, 62, 66 holes

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Figure 5, Index plate and sector

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Name…………………………………………… ID………………………… Date…….




1. Why an efficient and positive method of holding workplaces to the milling machine

table is important?

2. What is milling machine attachment, and why it is needed?

3. List down and explain at least three methods of mounting workpieces.


.



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Information sheet 5- Identification of processing and operating parameters

5.1 Introduction

This sheet is aimed at improving the effectiveness of cereal milling machines. It involves

steps like assessing of cereal products and cereal milling process, identification of the

cause of the problem, determination of factors recommendation. In this work, cereal

called rice taken in order to smooth the working activity.

5.2 Study of rice products and rice milling process

5.2.1 Rice products

The national bureau of agricultural commodity and foods standards, ministry of

agriculture and cooperatives, has divided rice seeds into three types according to milling

characteristics, namely, paddy husk, brown rice and white rice or milled rice. There are

four components to the structure of rice grains: husk, germ, rice bran, and endosperm.

The husk is the outermost layer which protects the exterior of the grain. It is made of

cellulose and hemicelluloses. Once the husk is removed, brown rice is obtained. The

brown rice is composed of rice germ (or embryo) and endosperm or white rice covered

by rice bran. Rice bran consists of layers of tissues covering the grain, and it is a rich

source of nutrient. The endosperm is the part of the grain that is consumed, primarily

consisting of carbohydrate in starch form.

For the sale of rice grains, whole kernels can be sold at a higher price than broken

grains. Whole kernels refer to intact rice grains containing no broken parts and including

at least 90 % of the grain length. Broken grains, on the other hand, mean broken rice

grains with lengths of at least 25% of the grain length. Broken grains also refer to split

rice grains with less than 80 percent of grain volume.

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Figure1. Cereal primary processing (in the milling machine)

Figure 2. Secondary processing of cereals (in the milling machine)

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Figure 3. Raw materials processing (store to medium milling machine)

5.2.2 Cleaning and grading operation

Cleaning process aims to protect the milling equipment, the quality of the milling

products and the consumer health. Foreign substance content and level of

contamination in the milled wheat batch are very important in achieving good quality in

flour. From this aspect, purchasing them based on the criteria and diligence is

paramount.

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Table 1. Cleaning and grading equipment

Equipment category Scale Name of the equipment

Cleaners S-M Seed Cleaners/Graders TA Range

M-L Seed Cleaners/Graders TAE Range

S-M Hand Operated Grain Cleaner

S-M Pedal-cum-Power Operated Grain Cleaner

S-M Rice Polishing Machine RS 40

S-M Rice whitener VSW 40

M-L Screen Air Separator

M-L Sab-Pre Cleaner and UB Fine Cleaner

Graders M-L Grain Cleaning Machine

M-L Grain Cleaner

M-L Grain - Seed - Flour Cleaner and Grader

M-L Mechanized Grader

Graders M-L Mechanized Grader

S-M Grain - Flour Separator

S-M Precision Air Classifier

M-L Gravity Separator

5.2.3 Quality control operation

Table2. Suppliers for testing and quality control

Equipment category Scale Name of Equipment

Temperature control S-M thermometer general purpose

Weight control S-M add and weigh scale

Volume control S-M mixer jugs

pH control S-M battery operated pH met

Brine control S-M Brine meter

Refractometers S-M Fisher brand Refractomete

Water treatment S-M Soda stream filter stream on line water filter unit

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5.3 Identification of the Cause of the Problem

After studying the components of the rice milling machine and parameters related to rice

milling, the causes of high rice breakage percentage were might found to be as follows:

Machine - Knob spacing adjustment, inadequate maintenance.

Method - Paddy rice flow rate, motor revolution speed.

People -Inadequate knowledge and skills on machine usage.

Raw Materials - Paddy rice moisture, rice strain, paddy rice storage.

5.4 Determination of Factors

Let us say, based on examination of each cause, three factors were found to likely

impact the breakage percentage of rice, namely, size of hopper feed, gap adjuster, and

outlet regulator. This research used the 3x3 full factorial experiment designs to search

for factors that significantly impact the rice breakage percentage. Each factor was

divided into three levels as shown in the Table1

Table 1. Factor levels

Factor Low Medium High

Input hopper rice (cm2 ) 4 8 12

White Rice Adjuster (cm) 3 4 5

Gap Rice Adjuster (mm) 4 5 6

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Name…………………………………………… ID………………………… Date…….




1. List down operations that can be performed in a milling machine.

2. Compare and contrast plain milling operation with the rest milling machine.




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Information sheet 6- Checking and adjusting equipment performance

6.1 Introduction

Reviewing workflow to adjust and keep equipment working properly can improve

productivity in the grain milling industry. Some of these maintenance tasks can be

performed by machine shop staff, while other tasks can be performed by the machine

owner. Below, we’ll look at just a few things you need to keep in mind to properly

maintain milling machines.

6.2 Lubrication

One way to keep tools for machine services in good condition is by making sure that

they are adequately lubricated. In order for machines to work properly, they must have

the proper lubrication that allows all parts to move smoothly. But before you start

lubricating your milling machine every five minutes, make sure you’re 100% aware of

how often you should be lubricating and how much lubricant you need to be using.

Precision is key when maintaining machine tools!

6.3 Cleaning

Another requirement for keeping a piece of machinery usable is making sure that is

properly cleaned after use. Many machine parts are often exposed to dirt and other

contamination, so it’s crucial to keep your machine clean to prevent any problems. If

you’re having any issues with operating your milling machine, dirt could be the culprit! If

you’re unsure where to look or you think your machine could use a professional

cleaning, take your machine to a machine shop. There, machine shop employees will

be able to provide a thorough cleaning and help prevent any problems from occurring in

the future. In addition, they can provide machine tool repair services if you find that

some part of your machine needs repair or replacement. Rebuilding tools certainly isn’t

an expense you should be paying often, so it’s a good idea to try and fix a small issue

before it takes a toll on your machines.

6.4 Daily Inspections

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By keeping up with daily inspections, you can prevent a problem from happening right

from the get-go. This is especially important if you’re using your milling machine on a

daily basis. If something is amiss and you start using your machine without thoroughly

inspecting it first, you may be in for a world of trouble. If something looks fine one day

and operates wrong the next, an inspection can catch the issue before it’s too late.

If you find any problem with your tool but are unsure of how to fix it, reach out to your

machine shop immediately for the fix or other tips. But until then, make sure you’re

practicing good maintenance with all of your machine tools.

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Name…………………………………………… ID………………………… Date…….




1. What are the few things you need to keep in mind to properly maintain milling

machines?

2. Why daily machine inspection is important?




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Information Sheet 7- Carrying out pre-start checks

7.1 Introduction

A visual “circle check” or pre-operational inspection of equipment prior to every use will

reduce the chance of equipment being operated in an unsafe condition. This makes it

easier to spot and deal with maintenance issues early before they turn into a problem

causing downtime, equipment damage or expensive repairs. Unsafe machinery can

also cause injury to the operator or other workers and damage to facilities or product.

7.2 Background

The Operator’s manual and maintenance records for each piece of equipment are

readily available to check on the need for operation procedure (oil and filter changes,

greasing, seal replacement and so on). Ensure maintenance records are checked

regularly and performed as scheduled or needed. Manuals and maintenance records for

our equipment are kept.

7.3 Caution

A pre-operational inspection of equipment is not the same as training to operate the

equipment. Do not operate or work with equipment unless you have been properly

trained to do so.

7.4 Safety rules & basics for milling machines

Milling machines are used to grind grains in the circular plate. The rotating bit is

extremely sharp and requires special safety precautions while being used. Be sure to

always follow good safety practices in the shop as described in general robotics safety

Rules. Specific safety requirements for milling machines are:

Do not make contact with the revolving cutter. Keep fingers at least 6” away.

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Even a non-revolving cutter is dangerously sharp- watch where you place your

hands

Remove spindle wrench immediately after securing bit in collet.

Place a wooden pad or suitable cover over the table surface to protect it from

possible damage…or just never place wrenches, hammers or other metal tools

on the mill table.

Use the buddy system when moving heavy attachments.

Do not attempt to tighten arbor nuts using machine power.

When installing or removing milling cutters, always hold them with a rag to

prevent cutting your hands.

While setting up work, install the cutter last to avoid being cut.

Never adjust the workpiece or work mounting devices when the machine is

operating.

Check and set the proper speed, feed, and depth of cut before cutting into the

metal

Chips should be removed from the workpiece with an appropriate rake and a

brush

Do not blow chips around or clean the machine slides with an air hose. Use

brushes and shop vac.

Shut the machine off before making any adjustments or measurements.

When using cutting oil, prevent splashing by using appropriate splash guards.

Cutting oil on the floor can cause a slippery condition that could result in operator

injury

When loosening a collet, tap the top of the draw bar with a soft face mallet

ONLY-no steel! (UNM-LA)

When engaging power table feed (UNM-LA), make sure no one is standing by

the table handles

Know how to indicate-in a vise and tram-in a head to make sure everything is

square

Some form of coolant or cutting fluid should be used when cutting metal

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Use parallels to position work in the vise, and be careful that the cutter doesn’t

make contact with the vise or table.

Keep vise jaws clean so that parts and jaws do not become “dented.”


Name…………………………………………… ID………………………… Date…….




1 Why milling machine carrying out pre-start checking is needed?.

2 What are these pre-start check lists?

3 What are the main purposes of grinding machines?




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Operation Sheet 1- Guidelines for correct grain storage

The following sequence is provided as a step-by-step example of a typical Guideline

for correct grain storage.

In order to attain correct and sustainable grain storage, Follow this guidelines.

Guidelines for correct grain storage

Make sure the storeroom is waterproof by locating it on well drained land, raising

it above the ground and fitting a waterproof roof

Prevent the temperature in the store from fluctuating by using insulating

materials (brick, mud, clay, wood or other insulation), painting the outside white

and fitting an overhanging roof to keep sunlight off the walls.

Ensure that the store is insect-proof, rat-proof and bird-proof

Thoroughly clean storerooms by removing and burning all old grain, straw,

insects etc. to prevent contamination of new grain

Make sure that grain is properly dried before putting it into a store

If chemical insecticides or fungicides are used, ensure that manufacturer’s

recommended dosages are followed.

Regularly check the grain for infestation, signs of mould or discolouration and

ensure that it is not getting hot (each is a sign of excessive moisture). If these

are found, remove the grain and re-dry it.

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Operation Sheet 2- Cleaning steps for excess zirconia dust avoidance

The milling chambers of units used for dry milling zirconia should be regularly cleaned

to avoid a build-up of excess. When dry milling zirconia recommended to use wet

cleaning process or wet grind, a restoration is essential at least once a week or after

every ten dry-milled restorations.

Steps of using cleaning hose and wet cleaning process

Remove the milling unit hose from the top of the suction device.

Connect the cleaning hose to the top opening of the suction device.

Activate the suction device’s manual function by changing the switch setting on

top of the device from “Auto” to “On”.

Vacuum excess dust from the chamber as needed.

Remove excess dust from the block shaft and the underside of the baffle

plate located on the block axis. (See both arrows in picture 4)

After the chamber has been vacuumed the wet cleaning process in the

software should be used 2-3 times as needed to remove excess dust.

In the software’s system menu, navigate to “Configuration“, then click on

the “Devices “button.

Select the applicable unit.

Click on the option “Service “then “Start a cleaning process“.

Notes: A restoration can be wet grinded to achieve a similar cleaning effect. A nylon

brush can also be used to remove zirconia dust from around the base of the block shaft

in between wet cleaning processes.

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Operation Sheet 3- Milling machine safe work procedure

The following Milling machine safe work procedure is provided, then it is must to wear

step-by-step following workplace health and safety regulations.

Milling machine safe work procedure

Properly use all personal protective equipment required.

Wear eye protection.

Wear appropriate footwear.

Appropriate attire.

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Operation Sheet 4– Procedures of mounting feed grinding machine

If cylindrical grinding is to be performed, such as grinding of workplaces mounted in the

grinding may be done with the work piece set up between centers, held in a chuck and

supported by a center rest, or clamped to a faceplate as in lathe setups. Use the

following methods when mounting the work piece between centers:

Use a dead center in the tailstock spindle. This method is preferred because it

eliminates any error caused by wear in the machine’s spindle bearings. Before

grinding check the accuracy and alignment of centers and correct if necessary.

To grind the centers, follow the procedures for grinding lathe centers

After the centers are accurate, align the centers by one of the methods prescribed

for aligning lathe centers.

Position the work piece between the centers, and use a lathe dog to revolve the

work piece.

Use the following methods and procedures when mounting the work piece for

conical grinding:

Work pieces for conical grinding can be set up in a chuck or between centers.

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The table is swiveled to the required taper by means of the graduations on the end

of the table (Figure 34.)

Since the table on a universal grinder is limited as to the degree that it can be

swiveled, steep conical tapers are normally ground by swiveling the headstock to the

angle of the taper desired (Figure 34).

Remember when a work piece is to be conically ground, the work piece axis and the

grinding wheel axis must be at the same height. Otherwise, the work piece will not

be ground at the correct angle.

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Draw and label correct selection of parallels which mounting in the Vise workpiece.

Figure. Mounting in the Vise workpiece

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Operation Sheet 5 – Rice milling process

Rice Milling Process

This is the initial stage of converting paddy rice into milled rice or brown rice that is

suitable for consumption. The grains have to be removed of excess humidity, to have a

humidity of 13-15 percent. The stages of rice milling process are as follows:

Paddy rice has to be cleaned to remove contaminants such as hay, vegetation,

dust, powder, gravel and sand from the paddy rice.

De-hulling is conducted to remove rice husks from the grains. In this stage, a

huller consisting of two rubber balls rotating into each other at different speeds or

a huller constructed of two steel panels padded with coarse stone is used to

create friction and remove the husks from the grain. The rice obtained from this

stage is brown rice, which still contains the fiber coating and embryo.

Whitening and polishing is the stage at which the rice bran is polished from the

brown rice, leaving only the endosperm. Rice bran is a byproduct of this stage.

In sorting the sizes of rice grains, sieves with openings for different sizes are

used to sort head rice from broken grains and rice ends.

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Operation Sheet 7 – Pre-operation of milling machine handling techniques

Do not operate or work with equipment unless you have been properly trained to do so.

Milling machine handling techniques

Task (Drawings, instructions, Specifications, Material… etc.) is clearly

understood.

Identify ON/OFF switch and emergency stop button and test any interlocking

devices (if applicable).

Make sure the machine is turned off or the emergency stop switch is

engaged, before comment of any work or inspection.

Ensure all security guards including the spindle guard are in place.

Ensure the work piece has been suitably prepared for the milling operation.

Ensure work piece is securely fastened to the working table.

Remove the chuck wrench/key immediately after installing the tooling.

Adjust speed and feed to suit the tooling diameter, material and turning

operation.

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Ensure the cutting tools are sharp, in good condition and secured.

Test the cooling fluid system operation and availability, if applicable.

Faulty equipment must not be used and must be immediately reported to the

shop technician

LAP Test Demonstration

Name----------------------------------- ID------------------------ Date--------------------------------

Time started: ________________________ Time finished: ________________

Instructions: Given necessary templates, tools and materials you are required to

perform the following tasks within 1 hour. The project is expecting you

to do it.

During your work: You can ask all the necessary tools and equipment

Lap Test Title: Produce Tool Shanks for Milling Machines

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Task Objectives / Demands: in accomplishing activities required for this project the

student will be able to: (During your work follow these steps)

LAP

Test

Demonstration

1 Show the guidelines for correct grain storage.

2 Practically show the steps help to use the cleaning hose and wet cleaning

process.

3 Perform milling machine safe work procedure

4 a. Draw and label correct selection of parallels which mounting in the Vise

workpiece

b. Perform the procedures of mounting feed grinding machine.

5 Apply or practically show the rice milling process.

6 . Perform pre-operation milling machine handling techniques

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Instruction sheet

This learning guide is developed to provide you the necessary information regarding the

following content coverage and topics:

Workplace information, policies and procedures.

Starting and operating the process

Monitoring equipment variation in operating conditions.

Identifying Variation in equipment operation.

Reporting maintenance as per workplace reporting format.

Monitoring and confirming process specification.

Removing fine bran from semolina and bran product.

Retuning fine bran product to purification or scratch rolls.

Identifying, rectifying and reporting out-of-specification product/process

outcomes.

Maintaining the work area with housekeeping standards

Conducting work with environmental standards and legislative requirements.

Maintaining workplace records



Follow workplace information, policies and procedures.

Start and operate the process

Monitor equipment variation in operating conditions.

Identify variation in equipment operation.

Report maintenance as per workplace reporting format.

Monitor and confirm process specification.

Removing fine bran from semolina and bran product.

LG #25 LO #2-Operate and monitor the milling and purification

process

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Return fine bran product to purification or scratch rolls.

Identify, rectify and report out-of-specification product/process outcomes.

Maintain the work area with housekeeping standards

Conduct work with environmental standards and legislative requirements.

Maintain workplace records








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Information Sheet 1- Workplace information, policies and procedures

1.1 Introduction

The workplace is the location at which an employee provides work for an employer.

That seems like a simple enough explanation, but it can become a bit more complex,

especially in today's knowledge economy.

.

1.2 Workplace information

Hand in hand with good manufacturing, hygiene and management practices, all

partners in the food supply chain must remain aware of the expanding number of

domestic and international food safety laws and regulations. Several incidences of food

contamination have led the Codex Alimentarius Commission to develop additional food

safety standards to enhance consumer health protection. These food safety laws,

regulations and standards are mandatory. To access markets, food commercial

enterprises must meet them through the application of good manufacturing/hygienic

practices (GM/HP) and hazard analysis critical control point (HACCP). The

implementation of sound quality assurance programmes is also a must to increase their

competitiveness.

1.3 Food safety laws

Millers and bakers should check the local laws with the Ethiopia National Bureau of

standards. In summary the registration of a mill or bakery involves the following:

Registration of the enterprise with the ministry of trade and industry

Obtaining a certificate of share capital (for limited companies), or a certificate

of incorporation for corporate companies.

Obtaining an occupational certificate from local authority, or the planning

authority in the land ministry

Obtaining a health permit or licence from the local authority or ministry of

health to allow the premises to be used for food production

Obtaining a manufacturing licence, issued by the local authority or ministry of

health

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Obtaining medical certificates from the health authority to certify that workers

are fit to handle food

Registration with the revenue office or tax office

1.4 Food regulations and standards

In Ethiopia there are both general regulations that apply to all foods and also

standards that are specific to particular types of food. Ethiopian National Bureau of

Standards should be consulted on details of the general regulations concerning:

Labelling

Presentation and advertisements

Weights and measures and

Hygiene practices during processing and handling

1.5 Food fortification regulations and standards

Millers and bakers should contact the ministry of health or the ministry of agriculture,

animal industries and fisheries for details of laws relating to public health, food safety

and hygiene and sanitation in their premises. Please note that parliament is considering

passage of a food safety bill or law that will complement the food safety strategic plan

and have broad-ranging impacts on all participations in the food chain. Small-scale

operators must remain in contact with the relevant enforcement agencies to remain in

compliance with the food safety bill or law.

1.5.1 Flours

Laws specify the maximum residue limits for pesticides etc. in grains and millers should

contact Ethiopian National Bureau of Standards for details. The moisture content of flour

cannot exceed 15% and the grade is specified by the allowable percentage of bran.

1.5.2 Labelling

Packaged flour should be labelled with the name and address of the miller and the

name of the flour (not the brand name but the type of flour (e.g. ‘maize flour’)). Flours do

not require date marking (e.g. ‘Best before’ or ‘Sell by’) if they are expected to have a

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shelf life of more than 12 months. Weaning foods made from cereal-legume mixtures

should conform to specifications of the Protein-Calorie Advisory Group of the United

Nations. As a minimum, the label on weaning food containers should have a clear set

of preparation instructions in the 100 languages spoken by customers and diagrams to

illustrate the preparation procedures, how often to feed the product and how much to

give the child. Label instructions should be fully tested among consumers of all

education levels and cultural backgrounds to ensure that they are properly understood.

1.6 Policy statement of intent

The health and safety policy statement of intent is often referred to as the health and

safety policy statement or simply (and incorrectly) as the health and safety policy. It

should contain the aims (which are not measurable) and objectives (which are

measurable) of the organization or company. Aims will probably remain unchanged

during policy revisions whereas objectives will be reviewed and modified or changed

each year. The statement should be written in clear and simple language so that it is

easily understandable. It should also be fairly brief and broken down into a series of

smaller statements or bullet points. The statement should be signed and dated by the

most senior person in the organization. This will demonstrate management commitment

to health and safety and give authority to the policy. It will indicate where ultimate

responsibility lies and the frequency with which the policy statement is reviewed.

1.7 Rules and procedures in grain milling operation

Any unsafe practice in grinding can be hazardous for operation and deserves careful

attention. Various important aspects in this respect are:

Grain mill selection: The milling machine for any grain milling operation should

be carefully chosen and the workpiece set up properly in the milling machine.

Milling machine inspection. Before mounting the wheel, it should be checked

for damage in transit, cracks and other defects. Ringing test is good enough

for vitrified bond wheels. Sound wheels, when tapped lightly at 45 from the

vertical line with a plastic hammer (non-metallic object) and listen for a brief

ring sound like a clear metallic ring. If there is a ring, the wheel is most likely

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oK, if it sounds dull/dead, do not use the wheel because the cracked wheel

will not ring.

Mill storage. When not used, the wheels should be stored in a dry room and

placed on their edges in racks.

Mounting of milling machine: The machine should be correctly mounted in the

spindle and enclosed by a guard. Wheel bore should not be a tight fit on the

sleeve.

Machine guards: These should always be used during milling, and

periodically adjusted to compensate for machine wear. Always fit wheel guard

securely in position closely over grinding wheel before starting machine, and

rotate spindle by hand before running on power to ensure wheels are free to

rotate and are not rubbing guards, fingers or fixtures.

Dust collection and health precaution: When grinding dry, provision for

extracting grinding dust should be made. Protective covers of machine should

never be removed while machine is in use. Operator should wear safety

devices to protect his eyes and body from flying abrasive particles and dust.

Wheel operation: Adequate power is essential in grinding machines. If power

is not adequate then wheels will slow down and develop flat spots, making

the wheel to run out-of-balance.

1.8 Setting up the machine

Inspect the mechanism to make sure nothing, aside from your stock, will

touch it, bind, or get caught on the equipment.

Keep the tool rest as close to the wheel but not touching it (gap should be

between 1/8” and 1/4”).

If the tool rest needs to be adjusted, unplug the machine first, and then adjust

it.

Where possible, always have the wheel rotation such that the grinding

pressure is into the support finger.

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Choose a finger most suited for the job. There is no definite shape to use, but

its length should be such that it gives adequate support to the work but is still

free to flex to allow it to trip from one work to another.

Fold back long sleeves up to the elbow.

No rings, wrist watches, bracelets, or other jewelry that could get caught in

the equipment.

1.8.2 Equipment using time

Make sure someone else knows that you are using the machine; press is

available in case of an emergency.

Be alert and cautious when using the grinding wheel.

Keep hands and arms well clear of rotating wheel (if you have long hair, make

sure it is tied back and will not touch the rotating wheel).

Gently feed the stock into the wheel, do not force it. Move it side-to-side to

avoid a hot spot on the wheel

Maintain good balance (stand erect with both feet straight and slightly apart)

while grinding your stock. Avoid leaning into the machine or stooping over the

wheel.

Clean up the shaving debris by using a brush or the shop vacuum to avoid potential

splinters from the shavings only after the equipment has been turned off, and the wheel

has stopped turning.

1.9 Repairs are necessary

If odd noise, excessive vibration, or if an unsafe condition is observed:

Turn machine off.

Unplug machine and install “Plug Lockout” device (give key to the teacher or

respective person) and install the “Tag out” label.

Do not repair it yourself.

Notify to your teacher, giving a description of what happened and your contact

information.

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1.10 Accident procedures

Administer proper First Aid; a kit is available in the specified work shop or room.

Call or if using Cell Phone for emergency assistance.

Seek medical help from Employee Health Services, or Student Health, or

Hospital (no need to phone them before going).

1.11 Workplace information systems template

Record the information to be stored or retrieved in the first column. Record the system

used to store/retrieve the information in the second column. Record your comment on

how effective you think the system is and what can be done to improve it in the last

column. An example has been provided.

Information/

information

type

System used to store and

retrieve information

Evaluation/suggested changes.

Photographs Currently photographs are stored

as hard copies in manila folders

that are filed in a cabinet.

Photographs are sorted in

categories and filed

alphabetically.

It is difficult to find the photos we

need with the method currently

being used. Many of them are

being damaged by being stored

in this way. It would be best to

store them electronically so they

can be shared more widely. We

could also then file images under

more than one category etc.

You could also comment on the

best software package to use or

record any other comments that

might be of value to management

in your organization.

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Name…………………………………………… ID………………………… Date…….




1. Define what workplace is.

2. Among Step-by-step procedure for grinding the bore of a bushing, list down at least

four of them.




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Information Sheet 2- Starting and operating the process

2.1 Introduction

This sheet might discus on starting (Pre-operational safety checks) and operating the

feed Mill process.

2.2 protective devices

Compulsory protective devices are:

2.3 Pre-operational safety checks

Prior to commencing operation of the milling plant operators must familiarize

themselves with all aspects of the mill and auger system to the operating

instruction contained in the mill manual.

Ensure area around Phase Converters is clear of any obstruction and electric

motors have good air flow around cooling fins. Switch on each Phase

Converter one at a time and check that both have powered up properly.

Check all nuts, bolts and attachments to ensure that they have not shaken

loose during operation.

Ensure that all covers and safety guards are fitted and operation signs

attached to plant.

Locate all emergency stop buttons and note their location.

Locate and identify all electric motor isolating switches.

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Check all electrical leads. Do not operate if electrical leads are damaged.

On the Main Switch Board, Inspect and identify all control switches and the

power for their operation.

If in doubt ask.

Ensure work site is clear of tools and other equipment or debris to prevent

tripping.

Ensure that there is sufficient ventilation for fumes and dust to dissipate to

enable safe operation.

2.4 Operational safety checks

Select silo for which grain is to be used.

Open the silo slide gate approximately 2 cm by moving the slide handle which

is located on the outer ring of the silo base. Note: If the slide gate is open

wider than 2 cm then additional vertical load is placed on the auger screw, but

no additional feed of grain will occur, so there is no advantage to do so. Once

grain is flowing, slide can be set to appropriate position to maintain required

flow.

Check that the bunk which is to have the rolled grain is clean and clear of

other plant.

Once the selected bunk is determined, position the lever below the mill

discharge auger in the correct position.

Shut off slide gate to allow all grain through mill system and then shut down.

To start electrical power: Follow switch order for mill start.

To start the mill: Check the restart button before starting the mill. Use the

control points at surge bin and drag auger to regulate output.

Mill Adjustment - the mill adjustment screw requires manual setting by

loosening the lock nut and adjusting the mill settings (with large spanner).

Lock nut to be fastened again when required setting is made.

In the case of a blackout the mill will need to be restarted. Do not restart the

mill under load. Use caution when restarting the mill.

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Once milling is completed the system will need to be shut down. Close the

silo slide first to clear the drag, the surge bin and roller mill in sequence.

Lockout for any work on the mill is achieved by the isolator switch located on

the control panel.

2.5 Production Process

The production of flour consists of the following three processing parts.

Wheat cleaning and moistening

Wheat milling

Wheat flour after treatment

2.5.1 Cleaning equipment and working principle

Cleaning equipment is mainly the use of wheat and impurities in the size,

weight, shape, gravity, magnetic and other differences to clean up. These

devices include the following categories:

Screening equipment: such as roller screen, vibrating screen, plane rotary

screen

Scourer Equipment: such as wheat scourer, wheat brush machine, impact

machine.

DeStone equipment: such as destoner, the specific gravity grading

machine

Selection equipment:Such as disk cylinder separator

Winnowing device: vertical suction duct, circulating air separator.

Magnetic separation equipment: permanent magnetic cylinder

2.6.1 Grain cleaning process flow

Pre-cleaning process

Raw wheat cleaning process

Net wheat cleaning process

2.6.2 Cleaning requirements

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Impurities no more than 0.3%;

Grain impurities not more than 0.5%;

Sandstone no more than 0.015%;

Nonmagnetic metal;

Note: Both Figures are simplified flour mill plant

2.6 Wheat milling

Wheat flour is wheat bran and endosperm and the embryo and endosperm separation,

then grinding into powder process. The wheat grain is composed of three parts of

endosperm, embryo and oatmeal. Each part by weight percentage: 82 -85%

endosperm, embryos of 2 ~ 3%, 12 ~ 14% oatmeal. Endosperm contains a large

number of starches, and contains some of the gluten protein composition; it is the main

raw material to make pasta products. Oatmeal containing more fiber, less nutrition,

mainly used as feed. For wheat and wheat germ mixed with wheat flour will affect the

color and baking, and easy to deteriorate during storage, the separation of two and the

endosperm, is a necessary step in wheat flour.

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Name…………………………………………… ID………………………… Date…….




1. Write down some cereal milling machine pre-operational safety cheeks.

2. What is wheat flour?




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Information Sheet -3 Monitoring equipment variation in operating conditions

3.1 Milling process

Succession of 3 systems

breaking

o breaks up grain in large pieces

o removing endosperm from bran

o as little flour and bran powder as possible

coarse reduction (scratching or sizing)

o removing small pieces of bran and embryo from endosperm

o smaller particles endosperm

fine reduction

o grinding endosperm into flour

o minimum in crushed germ and bran powder

o optimum in damaged starch granules

3.2 Roller milling

Fig 1. Milling

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3.3 Roller milling: break system

4-5 breaks, corrugated rolls

first break opens kernel

subsequent breaks: scraping endosperm from the bran

gradually smaller but more corrugations

differential from 2.5 to 1

3.4 Roller milling: reduction system

Gradual decrease of particle size into flour

Roller mill with smooth rolls,

differential 1.25 to 1

high shear pressure, lower shear forces

Coarse reduction: 3-5 stages

removing small pieces of bran and embryo from endosperm

smaller particles endosperm

no severe grinding: no bran in flour

Fine reduction: 6-10 stages

grinding endosperm into flour

minimum in crushed germ and bran powder

optimum in damaged starch granules

3.5 Hammer mill

impact milling

screen determines the particle size

requires dehulling when applied for ‘white’ flour/meal

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Figure 1 & 2. Hammer mill and sieve respectively.

3.6 Sieving: plansifter

Sieving stage follows each set of rolls

different mill fractions

directed to:

o Next break rolls

o Reduction rolls

o Purifier

o Finished product

3.7 Sieving

Purifiers

separation of pure endosperm and endosperm with different amounts of

bran

vibrating motion of sieves: heavier endosperm close to sieve, brannier

material on top

air currents fluidise and stratify according to size, specific gravity and

shape

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3.8 Milling and flour/meal quality

Particle size

Bran content -> ash content

Color

Starch damage

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Name…………………………………………… ID………………………… Date…….




1. Milling process has systems successions. What are they?

2. List down on what the milling and flour/meal quality depend?


Answer Sheet

Score = ___________

Rating: ____________



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Information Sheet 4 - Identifying variation in equipment operation

4.1 Introduction

Milling is the process of machining flat, curved, or Milling machines are basically

classified as vertical or irregular surfaces by feeding the workpiece against a rotating

horizontal. These machines are also classified as knee-type, cutter containing a number

of cutting edges. The milling rams type, manufacturing or bed type, and planer-type.

Most machine consists basically of a motor driven spindle, which milling machines have

self-contained electric drive motors, mounts and revolves the milling cutter, and a

reciprocating coolant systems, variable spindle speeds, and power-operated adjustable

worktable, which mounts and feeds the workpiece table feeds

4.2 Milling machine parts

A milling machine consists of the following parts: Base, Column, Knee, Saddle, Table,

Overhanging Arm, Spindle, Arbor, Arbor Supports, Milling Head, and Ram

4.2.1 Base

It is the foundation part of a machine and all other parts are joined on it. It carries the

entire load so it should have high compressive strength and it is made up of cast iron.

4.2.2 Column

It is mounted vertically on the base. It supports the knee, table, etc. and work as

housing for the other entire driving member. The column is a hollow member which

contains driving gears and sometimes motor for the spindle and the table.

4.2.3 Knee

It is a casting that supports the saddle and table. All gearing mechanism is enclosed

within the knee. It is fastened to the column by dovetail ways. The knee is supported

and adjusted by a vertical positioning screw (elevating screw). The elevating screw is

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used to adjust the knee up and down by raising or lowering the lever either with the help

of hand or power feed.

4.2.4 Saddle

This is placed between the table and the knee, and work as an intermediate part

between them. This can moves transversally to the column face. This slides over the

guide ways provided situated on the knee which is perpendicular to the column face.

The main function is to provide motion in a horizontal direction to the workpiece.

4.2.5 Sable

This is a rectangular casting which is present on the top of the saddle. The table is

situated over the knee. It is the part of a machine that holds the workpiece while

machining. This is made by cast iron and has T-slot cut over it. This provides vertical

motion by moving the knee up and down. It provides horizontal motion by the feed

screw. This provides a horizontal (transverse) motion by moving the saddle.

4.2.6 Overhanging arm

The overarm is used to fastened arbor support. It may consist of one or two cylindrical

bars that slide through the holes in the column. It is made by cast iron.

Spindle: The spindle is the main part of the machine which holds the tool in the right

place. This spindle provides the drive for arbors, cutters, and attachments used on a

machine.

4.2.7 Arbor

This is a mechanical part, which is used as an extension part of the spindle in a

horizontal mill machine. It is fitted on the spindle whenever it's required. This holds the

tool and moves it in the correct direction.

4.2.8 Arbor Supports

There are generally two types of arbor supports used in the mill machine. The first one

has a small diameter bearing hole, 1-inch in maximum diameter, and the other one has

a large diameter bearing hole, usually up to 23/4 inches. The arbor support has an oil

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reservoir that lubricates the bearing surfaces. It can be clamped anywhere on the

overarm. The arbor support is used only in the horizontal types of milling machines.

4.2.9 Milling head

It is the upper section of a vertical mill machine. It consists of a spindle, driving motor

and other controlling mechanisms.

4.2.10 Ram

One end of the arm is attached to the column and other ends to the milling head. The

ram can be moved transversally ( in and out) on the column by a hand lever.

Milling is the process of machining flat, curved, or Milling machines are basically

classified as vertical or irregular surfaces by feeding the workpiece against a rotating

horizontal

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Name…………………………………………… ID………………………… Date…….



Test: Short Answer Questions

1. Define what milling is. (3 points)

2. List down almost the all feed milling machine parts. (7 points)

Information Sheet 5 - Reporting maintenance as per workplace reporting format

5.1 Equipment maintenance

Another reason for lost production is delays caused by waiting for spare parts after

equipment breaks down. As a minimum, cereal processors should monitor the state of

equipment that is likely to wear out and as their experience grows over the years, they

should buy spare parts or send the machine for servicing when they expect that a

component is due to be replaced. There are likely to be a few parts that wear out more

quickly than others (e.g. mixer bearings, heating elements in bag sealers, drive belts

and hammers in mills). Processors can make an agreement in advance, possibly

involving a small annual fee, to ensure that electricians or mechanics repair equipment

as a priority. Lack of maintenance is one of the most common problems that cause

small-scale millers and bakers to lose money. Machine breakdowns arise from a

number of different causes. They reduce productivity and increase production costs.

Poorly maintained machines also produce substandard products and can contaminate

products with metal fragments, as well as being a potential hazard to operators. Another

common cause of failure is when those who operate or maintain a machine arbitrarily

alter it. Proper maintenance ensures that machinery operates correctly and safely and



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prolongs its life, thus reducing capital and operating expenditure. To put preventive

maintenance into practice, the following actions are needed:

Identify priority machinery which have components that wear out more frequently

Make a clear description of the procedures and standards for the work of

machine operators and maintenance workers (such as lubricating, tightening

bolts, adjustments etc.) In daily, weekly and monthly routine maintenance plans

Organise a schedule and train staff to implement maintenance plans.

Prepare a maintenance budget

Record inspection results, analyse the records and evaluate the success of

maintenance

Continuously update procedures and standards.

5.2 Maintenance and inspection

Maintenance Work equipment needs to be properly maintained so that it continues to

operate safely and in the way it was designed to perform. The amount of maintenance

will be stipulated in the manufacturers’ instructions and will depend on the amount of

use, the working environment and the type of equipment. High speed, high risk

machines, which are heavily used in an adverse environment like salt water, may

require very frequent maintenance, whereas a simple hand tool, like a shovel, may

require very little.

Figure 1. Typical maintenance notice

Maintenance management schemes can be based around a number of techniques

designed to focus on those parts which deteriorate and need to be maintained to

prevent health and safety risks. These techniques include:

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Preventative planned maintenance – which involves replacing parts and

consumables or making necessary adjustments at preset intervals, normally set

by the manufacturer, so that there are no hazards created by component

deterioration or failure. Vehicles are normally maintained on this basis

Condition based maintenance – this involves monitoring the condition of critical

parts and carrying out maintenance whenever necessary to avoid hazards which

could otherwise occur

Breakdown based maintenance – here maintenance is only carried out when

faults or failures have occurred. This is only acceptable if the failure does not

present an immediate hazard and can be corrected before the risk is increased.

If, for example, a bearing overheating can be detected by a monitoring device, it

is acceptable to wait for the overheating to occur as long as the equipment can

be stopped and repairs carried out before the fault becomes dangerous to

persons employed.

In the context of health and safety, maintenance is not concerned with operational effi-

ciency but only with avoiding risks to people. It is essential to ensure that maintenance

work can be carried out safely. This will involve:

Competent well-trained maintenance people

The equipment being made safe for the maintenance work to be carried out. In

many cases the normal safeguards for operating the equipment may not be suffi

cient as maintenance sometimes involves going inside guards to observe and

subsequently adjust, lubricate or repair the equipment. Careful design allowing

adjustments, lubrication and observation from outside the guards, for example,

can often eliminate the hazard. Making equipment safe will usually involve

disconnecting the power supply and then preventing anything moving, falling or

starting during the work. It may also involve waiting for equipment to cool or

warm up to room temperature

A safe system of work being used to carry out the necessary procedures to

make and keep the equipment safe and perform the maintenance tasks. This

can often involve a formal ‘permit to work’ scheme to ensure that the correct

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sequence of safety critical tasks has been performed and all necessary

precautions taken

Correct tools and safety equipment being available to perform the maintenance

work without risks to people. For example special lighting or ventilation may be

required.

5.3 Inspection under the provision and use of work

Equipment Regulations Complex equipment and/or high-risk equipment will probably

need a maintenance log and may require a more rigid inspection regime to ensure

continued safe operation. This is covered by PUWER 98, Regulation 6. PUWER

requires that where safety is dependent on the installation conditions and/or the work

equipment is exposed to conditions causing deterioration, which may result in a signifi

cant risk and a dangerous situation developing, that the equipment is inspected by a

competent person. In this case the competent person would normally be an employee,

but there may be circumstances like fairground equipment, where an outside competent

person would be used. The inspection must be done:

After installation for the first time

After assembly at a new site or in a new location and thereafter

At suitable intervals and

Each time exceptional circumstances occur which could affect safety

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Maintenance and Repair Report Format


Name…………………………………………… ID………………………… Date…….



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1. Why proper maintenance is required? (3 points)

2. List down the actions that can put preventive maintenance into practice. (5

points)


Answer Sheet

Information Sheet 6 - Monitoring and confirming process specification

6.1 Introduction

Modern countertop grain mills make it easy for anyone to grind fresh, flavorful flours.

There are dozens of flour mills from which to choose. Fortunately, the search for an

ideal mill can begin with three basic decisions: what power source to use, the

appropriate milling mechanism and the maximum flour temperature to tolerate. Many

mills are appropriate for family use as well as in a bootstrap business. The decision

comes down to price, quality, versatility and convenience features.

6.2 Power Source

Manual Mills: For the energetic, athletic, disciplined person, a manual mill (particularly

the large flywheel type) can be a superb choice, with a low chance of nutrient-damaging

heat buildup. But most manual mills require work, so be realistic — if there’s no flour,

there can be no bread.

Electric Mills: If the primary objective is getting the flour ground and the bread on the

table without any fuss, frills or fanfare, then an electric mill’s primary drawback — loss of

Score = ___________

Rating: ____________



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use during power outages — may be acceptably rare. The zippiest, cleanest, easiest

mills in this category are relatively inexpensive, and they do one heck of a job, then go

back in the cupboard.

Convertible Mills: Many mill manufacturers have devised ways to make their mills

convertible from manual to electric or vice versa, so grinding continues with or without

power. It is important to select a convertible mill that works properly in either mode

because some don’t.

6.3 Milling mechanisms

Each grain mill has some mechanism for crushing, beating or grinding grain into meal,

usually in a range of textures from coarse to fine. Some mechanisms are more versatile

than others: They grind hard, soft, oily or wet items. Aside from the increasingly popular

“oat roller,” two milling mechanisms dominate the home mill market: burr and impact.

Burr mills are the most common. They have two grinding plates, one fixed and the other

rotated by a power source. The grain is fed into a gap between the burrs, which are

grooved to aid the shearing and crushing of the grain. Composite stone burrs are

constructed by pressing natural or artificial stones (and sometimes metal cutting blades)

in a bed of cement. Metal burrs/plates, some of which are flat and some cone-shaped,

are constructed of hardened cast steel or other metal. Basically, stone burrs tend to

crush the grain, and metal burrs tend to break and shear it.


Name…………………………………………… ID………………………… Date…….




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3. List down the two main power sources of feed mill. (5 points)

4. List down the three basic decisions for an ideal mill search can begin. (5

points)


Answer Sheet

Information Sheet -7 Removing fine bran from semolina and bran product

7.1 Fine tuning the purification process

In a wheat mill, purification is achieved when fine bran and germ are separated from

endosperm particles to increase the purity of coarse endosperm (farina or semolina). In

durum semolina production, purifiers are essential to finished product quality and work

by removing fine bran and compound particles (large endosperm with attached bran)

from the finished semolina. In a flour mill, the objective of the purification system is to

separate clean farina, or coarse endosperm, from fine bran or compound particles to

feed the primary reduction rolls. This purification step allows the miller to maximize

extraction of low ash, bright color flour. While a purifier is the most common component

of a mill purification system, purification can be achieved in all mills with and without

additional purification equipment.

7.2 Using Roller Mills and Sifter

Purification is achieved in the milling process by using roller mills and sifters. Using

smooth rolls to gently grind key collection stocks commonly referred to as Quality or

Score = ___________

Rating: ____________



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Sizings passages in most American flow diagrams, small bran and germ particles are

flattened while endosperm particles are further reduced.

The gentle compression from a smooth roll with low differential increases the particle

size of bran and germ allowing each to be removed with the top scalping sieves of the

sifter. Many soft wheat flour mills rely solely on purification from rolls and sifters since

the soft endosperm breaks down more easily into small particles or flour.

This milling characteristic of soft wheat yields few coarse particles, or farina, which

would be suitable for purification with the purifier, therefore making the use of purifiers

less effective. One challenge is managing the grinding practices as the natural tendency

is to grind too hard on these key passages, breaking the bran and germ and eliminating

opportunity to remove them in the sifter and purify the stock. In most other cases a

purifier is necessary to produce low-ash flour and bran-free semolina, and proper set-up

is important for optimal separation.

7.3 Stratification of the Stock

When using a purifier to separate good endosperm from bran and compound particles,

the key is proper stratification of the stock. Stratification, or layering of the stock in the

purifier, is achieved by combining a reciprocating or vibratory agitation with the gentle

upward flow of air evenly through the product. The principle of terminal velocity is the

resistance to air flow particles have depending on their shape. Irregularly shaped or flat

particles have greater resistance to air flow than round particles. Larger particles of

similar density will have greater resistance to air flow than smaller particles.

For a purifier to be effective, stock of similar-sized particles is fed from a sifter. The

stock has a range of particle shapes and densities. When the stock is exposed to the

mild agitation and upward air flow, lighter particles float to the surface and the heavier

particles will sink to the bottom. Small, heavier particles fall faster, allowing the purifier

to grade farina into particle size ranges for efficient grinding.

The smallest, cleanest farina falls through the air current and sieves at the front or head

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of the purifier, while slightly larger farina falls through the end of the purifier sieve deck.

The irregular shaped compound particles and flat bran particles float to the end of the

purifier decks and tail over. Controlling the air through the purifier is critical to its

operation. Stratification of material in the purifier is destroyed by intense agitation, often

the result of too much air being drawn through the mixture of particles. With too little air,

the stock will not separate.

A visual inspection by the miller of the stock feeding the purifier as compared to the

stock leaving the purifier can confirm that the stock is being properly stratified. The

figure on page 64 illustrates stock for a first purifier (P-1) from a first or second break

sifter using the most common triple deck purifier. When the stock in the purifier is

properly stratified, the first product through the head sieves will be the cleanest

endosperm and the smallest particle size. The product through the tail sieves will be

clean endosperm, but larger in particle size.

This happens as the larger particles of the same density have a lower terminal velocity.

As for the stock tailing over the three sieve decks, the stock tailing over the bottom

deck should look similar to the stock feeding the purifier. The stock on the top deck

should be the coarsest bran, and the middle should be smaller, but similar in purity

when compared to the top deck. This rule of thumb works well for break purifiers.

However, as the average particle size of material feeding a purifier gets smaller,

maintaining a good separation of stock in the purifier is more difficult.

7.4 Loading of Purifiers

Proper loading and clothing of the purifier sieves is critical to the effectiveness of the

separations made by the purifier. Purifier capacity is determined by the width of the

deck and is measured in pounds or kilogram per hour per inch or millimeter of deck

width. The load is very dependent on the particle size of the stock as well. Purifiers

must always be fed from a sifter or from another purifier. The larger the average

particle size, the greater the load can be to the purifier. However, to optimize the

separation from the purifier, a smaller micron range of the stock feeding the purifier is

preferred. Generally a range of 200 to 400 microns from the sifter is optimal.

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Purifiers can be classified in two general categories based on what type of mill stock is

feeding them. Break purifiers receive stock from break sifters. Generally, coarse

middlings or sizings stock come from primary breaks, but fine middlings from

secondary break passages may be sent to purifiers as well. Reduction purifiers receive

stock from sizings sifters or from other purifiers. The purifier clothing must be sized to

match the stock. As a general rule, the clothing of the first purifier sieve should be 2 to

four grit gauze numbers coarser (50 to 70 microns) than the sifter sieve clothing that

the stock passed over. The intermediate purifier sieves should be evenly spaced with

the last purifier sieve approximately two grit gauze sizes coarser than the sifter sieve

clothing which the stock came through.

7.5 Conditions for effective purifiers

For purifiers to effectively separate and grade stock, the balance of air and product must

be consistently maintained. This balance starts with the feeder gate to the purifier. The

stock must be fed across the entire width of the sieve and it must travel evenly down the

full length of the sieve. The purifier clothing on the sieves must be in good condition,

free of patches and holes. The sieve cleaners, either brushes or ball, must operate

effectively to keep the sieve surface free from buildup and blinding over. Air flow is

critical, and air will always flow to the path of least resistance. Any inconsistency in the

flow of stock or the condition of the sieves will result in inconsistency of air flow. To

check and maintain effective purification, sieves should be hand brushed weekly and air

chambers should be checked regularly for the build-up of dead stock.

7.6 Deciding on purification

Few modern flow diagrams have no purifiers in the process and many diagrams use

several purifier passages. There are several advantages and disadvantages to be

considered when deciding how to use purifiers in a mill flow. A significant advantage is

the ability to grade stock and balance the load to various roll passages while the mill is

operating. Unlike a sifter, purifier sieves can be pulled out and changed while the mill is

running under load. Purifier tips or valves can be adjusted as necessary to redirect

stock based on mill load or quality if there is a change in the wheat or mill environment

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impacting mill balance. Purifiers help to increase flour production of low ash flour at the

head end of the mill. By removing fine bran, purifiers enable the use of impact mills on

certain stock without significant change to flour quality. The use of purifiers also allows

for the production of high quality farina as a finished product if desired.

However, there are several disadvantages to using purifiers as well. As stated at the

beginning of this article, smooth rolls can serve the same purpose as purifiers in many

cases depending on wheat type and the quality desired of the finished flour. Purifiers

will dry out the stock if the environment of the mill is not controlled appropriately.

Purifiers require training for millers to understand how to monitor their operation and the

attention it takes keep the sieves clean and working properly.

Added maintenance, air and filter requirements, electrical usage and capital expense

must all be considered when deciding how much purification is needed to produce the

quality of flour desired.


Name…………………………………………… ID………………………… Date…….



Test : Short Answer Questions

1. List down the two main power sources of feed mill. (5 points)

2. What is the objective of purification system? (5 points)


Answer Sheet

Score = ___________

Rating: ____________



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Information Sheet 8 - Retuning fine bran product to purification or scratch rolls

8.1 Break roll spirals.

The types of particle are separated one from the other according to size by scalping,

dusting and grading. The over tails of the wire scalping sieve (bran coats) become the

feedstock to the second break. The finer stocks are graded and conveyed to be purified

in preparation for appropriate further treatment on reduction mills, except for the flour,

which is a finished product and is retained for blending with other machine flours. The

feed to the subsequent breaks consists of the break stock scalped from the grind of the

previous break. The scraping action of the break rolls is achieved by a combination of

their fluted surface and the speed differential of 2.5:1 at which they run. The flutes run in

a spiral: 1 5 0 is typical for break rolls running at 550/220 in the first and second breaks

and 1:24 for subsequent breaks. Flutes vary in size from mill to mill, but on a 250 mm

diameter roll they might be:

1st break 3.24.1 per 10 mm;

2nd break 5.1-5.7 per 10 mm;

3rd break 6.4-7.0 per 10 mm;

4th break 8.6-9.6 per 10 mm;

5th break 10.2-10.8 per 10 mm.

Wear on flutes reduces their sharpness, leading eventually to the need for refluting, the

interval at which this occurs varying from about six months upwards. Many rolls run

sharp-to-sharp, but with new rolls, while the extreme sharpness is wearing off, the fast

roll may be run in the dull mode. Some millers consider that, if first break rolls are run

dull-to-dull, large flakes of bran are produced, while it is claimed that sharp-to-sharp

cuts the bran into small flakes which are difficult to clean. Dull-to-dull fluting tends to

produce more break flour than sharp-to-sharp at similar releases. In any of these

relationships the slow roll serves to ‘hold’ the stock while it is scraped by the fast roll

surface. As the bran passes down the break system, the gap between the rolls declines

appropriately to the thinner bran flakes. In each grinding stage the bran becomes

progressively cleaner until, following the last break grind, it can yield no more

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endosperm through further grinding. It may become the finished byproduct ‘bran’ at this

stage or it may be subjected to treatment in bran finishers. A bran finisher consists

essentially of a hollow cylinder, two thirds of which is perforated. Scalping’s are fed into

the horizontally disposed cylinder and finger beaters, attached to a central shaft, rotated

at high speed and the bran skins are propelled against the perforated cover. Some of

the remaining endosperm is rubbed off and passes through the apertures. Clean bran

over tails the machine. The through contain small fragments of bran and require further

sieving but, because they are ‘greasy’ and would blind plansifters, they are dressed on

special sifters such as vibratory sifters. Break release.

The break release throughs of the scalper cover) varies among mills. The criteria

determining selected proportions are:

The number of break stages;

The grist; larger releases on first break are typical for soft wheat’s, followed by

lower releases on succeeding breaks;

Specifications of the finished products, for example, higher early break releases

may be advisable when milling a large proportion of high grade flours. It is

generally considered desirable to release on breaks about 10% more stock than

is required in the straight-run (total) flour, subsequently rejecting the 10% from

the scratch and reduction systems as fine wheat feed. Typical break releases,

expressed as percentages of the individual break feeds, and of the feed to 1st

break; and the usual

8.2 Systems in flour mill process

8.2.1 Bran mill system

The function of bran mill is to peel wheat kernel and scrap endosperm from wheat

grains, and then use flat screen to classify the particles; the wheat residue, residue that

is connected with bran, and wheat core are delivered to purifying system for extracting

more pure wheat residue and core. The final bran milling system is mainly used to scrap

all the endosperm left on bran flake. There are totally 5 bran mills in this system: 1st and

2nd bran mill is mainly for crushing and extracting wheat residue and core, but the flour

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extraction rate is low; 3Bf bran mill is mainly for grinding the wheat residue that is

extracted from 2nd mill, while 3Bf is to grind the first layer screened material, and its flour

extraction rate is also low; the 4th bran mill can grind coarse and fine particles

separately. At the middle and end stages, there are bran brusher and bran finisher to

make sure bran purity and decrease power leakage.

8.2.2 Scratch mill system

The scratch mill in wheat flour mill process is to process the coarse particles from bran

mill, or endosperm that is connected with bran. Its grinding roller scraps lightly to

separate wheat bran from endosperm; after sieving, wheat core and coarse flour with

little bran are extracted, and then delivered into core mill system for extracting high

quality wheat flour. At the same time scratch mill system also extract a proportion of

flour.

The scratch system has 2 paths. The contacting length of scratch system grinding roller

is generally 0.8-1.2mm/ (100kg wheat*24h), which takes 7% to 10% of the whole purifier

grinding roller length. As this 300ton/d flour mill adopts hard wheat as raw material, it

applies the system of “first purifying, then wheat residue enters”. The main features of

this process are: wide range of purifying, high extraction rate of 1st grade coarse grain

particle, the material that enters scratch mill has similar quality and weight, and the

grinding rotation rate is suitable for processing wheat with high hardness.

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8.2.3 Purifying system

The purifying system in wheat flour mill process is used to purify the wheat residue, core

and hard coarse flour which were extracted from bran mill and scratch mill and divide

them into husk, endosperm with bran and pure endosperm participles by weight. The

pure wheat core is delivered to core milling system; wheat residue is delivered to

scratch milling system, while wheat flakes are delivered to tail mill or fine bran mill

system separately for processing. This can avoid bran and core from mixing into flour,

which also increases high quality flour extraction rate.

Those material enters purifier must be graded, and flour must be cleared away. The

material that enters the machine must be in uniform size, so that the operator can

choose proper sieve for purifier, and it shall also be equipped with adequate amount of

air flow to make sure purifying effect. Otherwise, if there is flour mixed in the material

that will enter purifier, or their particles have great disparity, it is hard to guarantee these

particles can evenly be spread on the sieve; as a result, the material may be pushed

slowly, and small particles may be sucked away with air, which greatly decreases

purifying effect.

There are totally 4 paths in purifying system. It utilizes the combined action of wind and

sieve to purify coarse flour and particle, which can better decrease product ash content

and increase yield.

8.2.4 Core mill system

The function of core mill system is to grind the relatively pure endosperm particles that

were gained from bran mill, scratch mill and purifying system into fine flour, while at the

same time decrease the breaking of wheat bran and wheat germ possibly. It can keep

the quality of wheat flour. After bolting (sifting), small bran flakes are delivered into tail

mill, the wheat core that has not been made into flour will be fed into next core mill for

grinding again, while the flour that meets requirements will be sifted out in time.

In order to improve flour quality, the core mill system in flour mill process adopts smooth

rolls, which decrease the breaking of starch granules in flour; at the same time the

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smooth rolls are processed by abrasive blasting, so that the roll will have rubbing to

materials, and grinding effect is improved to guarantee cortex integrity and flour quality.

As the flour is easily extruded into flakes between rollers and influence sieving effect of

plansifter, a wheat flour detacher is equipped in core mill system.

The incoming material of core mill system have non uniform quality: 1M, 2M and 3M

incoming material has relatively low ash content, so these 3 core mills grind a majority

of flour, which is also the main source of special purpose flour. The final stage of core

mill mainly produces wheat middling.

8.2.5 Tail mill system

Tail mill is usually designed at the milled or end of core mill. Its function is to process

tiny bran pieces from core mill, scratch mill, bran mill and purifying system, and also

small particle flour that is connected with bran. After the slight grinding of tail mill, and

sieving, different quality wheat core will be delivered into final core mill for grinding.


Name…………………………………………… ID………………………… Date…….




1. ____________ is a finished product in the cereal mill operating

process. (3 points)

2. List down the systems in flour mill process and give explanation on

Purifying system. (7 points)


Answer Sheet Score = ___________

Rating: ____________



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Information Sheet 9 - Identifying, rectifying and reporting out-of-specification

Product/process outcomes

9.1 Introduction

Because of their extensive use as human foods, the safety and microbiology of cereal

grains and its products are highly concerned. The sources of the microbial

contamination of cereals are mainly contributed by the environment in which the crops

are grown, handled, and processed, which includes the air, soil, water, animals,

shipping containers, and processing equipment. Microbial food spoilage is defined as

deprive of good or effective food qualities as a result of microbial activity. Microbial food

spoilage can be identified and is visible in the form of surface slime or colonies, loss of

texture, or presence of by-products of microbial metabolism such as gas, pigments, off-

odours and flavours, or in combination of the above. However, this quality can be

subjective as each individual judges its unacceptability differently. In this study, the

microbiology of cereal grains and cereal products (dried cereal products, bread, pasta

and noodles) and its preservation are being studied.

9.2 Microbiology of cereals and cereal products

As mentioned previously, the microbiological contamination of cereal grains begins at

the growing phase of the grains. The intensity of the contamination can increase during

the growth and after harvest, resulting in the spoilage of the final products or worse,

induces foodborne illnesses in the consumers if appropriate control measures are not

taken.

9.2.1 Cereal Grains

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The spoilage of cereal grains is commonly associated with moulds, and some of these

moulds can be toxigenic. However, bacilli, some enteric bacteria, lactic acid bacteria,

and micrococci can also contaminate the crops which may cause problems in the

supply chain when products are made. The moulds affecting the crops can be

categorized into two groups: the field fungi and the storage fungi.

The ‘field fungi’, consist primarily of the genera Fasarium, Cladosporium, Alternaria, and

Helminthosporium, are moulds infecting the grains before harvest. At this stage, a large

number of such microorganisms are accumulated and these moulds grow on grains with

aw of 0.90 or higher or 18 to 30% moisture. On the other hand, the ‘storage fungi’ are

those that infect post-harvest grains, consist primarily of the genera Rhizopus,

Aspergillus, Penicillium, Mucor, and Wallemia growing at low moisture contents (14 to

16%).

Under favourable growth conditions, these moulds can produce mycotoxins, such as

aflatoxins, nivelanol, fumonisins, and deoxynivalenol. Mycotoxins are difficult to be

completely removed by processing treatments used for cereals. Therefore, it is very

crucial to control the prevalence of mycotoxin production to avoid food poisoning in the

consumers. The presence of certain bacteria and fungi can cause crop diseases in the

plants, which can lead to spoilage of the harvested grains and thus reduced crop yields.

Besides direct damage by the fungal growth, it can also results in the occurrence of

chemical (by enzyme of fatty acid production) or physical (by spontaneous heating due

to fungal activity or moisture and heat from insect contamination) damage in the grains.

9.2.2 Dried cereal products

Breakfast cereals, snack foods, oatmeal, rice cakes, and infant cereals are examples of

dried cereal products that are typically ready to eat (RTE) without the need of further

cooking, though some are optional to be heated with added hot water or milk. Dried

cereal products have water activity <0.5 which can inhibit the proliferation of most

microorganisms except moulds, thus reducing the possibilities for the occurrence of

microbiological hazards. In relation to that, foodborne illnesses associated with cereals

are less common as long as proper storage practices are followed to ensure the

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exclusion of water, insects, birds, and rodents. In contrast, Bacillus spp. may grow if the

water activity is favourable for growth.

On the other hand, the contamination can be from the environment or the ingredients. If

the raw grains are already contaminated with the production of mycotoxins from fungi, it

is quite likely that the cereal products are to contain mycotoxins too. Thus, tests for

mycotoxins are appropriate in cereal products. On the other hand, United States

Centers for Disease Control and Prevention (CDC) also reported two Salmonella Agona

outbreaks in 1998 and 2008 associated with breakfast cereals, in which the

investigations revealed that the cause of these outbreaks was related to the

contamination of the processing line in the manufacturing plants. In terms of microbial

spoilage, it is less likely to occur in dried cereal products due to its low water activity

unless the other ingredients added such as nuts and cocoa are contaminated.

9.2.3 Breads

Lactic acid bacteria may grow and contributes to the sourness in raw bread dough by

producing lactic acid as end products. A notable point is that Salmonellae and Bacillus

cereus may also be present in the raw dough. However, this will not be a major problem

as these bacteria can be destroyed when the dough is cooked at high temperatures to

attain its desired texture, colour, and structure. In addition, this process also dehydrates

the surface of the breads which in turns inhibits the growth of microorganisms on the

surface. Though baking can destroy the moulds in dough, recontamination can still

occur. The water activity of bread which is higher than 0.96 and with pH of about 5.5 to

6 gives favourable conditions for the growth of moulds. These moulds can be a great

hazard to the consumers as they can produce mycotoxins

9.2.4 Pasta and noodles

Pasta and noodles are categorized into two groups: fresh and dry pasta. Dry pasta is

made by mixing finely grounded semolina flour and water into a paste and then form

into the desired pasta shapes. This type of pasta has a long shelf life at ambient

temperatures due to its low moisture content resulted from the drying process at low

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temperature that lasts for several days. In contrast, fresh pasta has an extra ingredient

egg incorporated in the dough, giving a higher water activity as compared to dry pasta.

Since dry pasta has low water activity, its microbial hazards and spoilage are of less

concerned, except if the flour used is contaminated with mycotoxins production by

moulds.


Name…………………………………………… ID………………………… Date…….




1. The sources of the microbial contamination of cereals are mainly contributed by

the environment. Give further explanation. (7 points)

2. What is the consequence of the spoilage of the final products? (3 points)


Answer Sheet

Score = ___________

Rating: ____________


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Information Sheet 10 - Maintaining the work area with housekeeping standards

10.1 Introduction

Effective housekeeping can eliminate workplace hazards and helps get the job done

easily and properly. A good housekeeping program plans and manages the orderly

storage and movement of materials from point of entry to exit. It includes a material flow

plan to ensure minimal handling. Worker training is an essential part of any good

housekeeping program. They should be reporting any unusual conditions or hazards as

well as obeying posted warning signs. The final addition to any housekeeping program

is inspection. It is the only way to check for deficiencies in the program so that changes

can be made.

10.2 Floors and other areas

Clean up spills such as oil on floors immediately. Floors should be free of debris and

accumulations of dust. Areas that cannot be cleaned continuously, such as

entranceways, should have anti-slip flooring. Replace any worn, ripped or damaged

flooring that poses a tripping hazard. Any equipment or tools not in use should be

removed from the work area. In the yard area, cut down and remove weeds and brush

from around buildings. They can hide tripping hazards.

10.3 Maintain light fixtures

All buildings and yards should be adequately lighted. Dirty light fixtures reduce

essential light levels. Light fixtures in storage areas containing combustible materials

should be protected against breaking (i.e. explosion proof fixtures). Maintain lighting

evenly; shadows mixed with light spots may cause trouble for people with weaker

eyesight.

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10.4 Aisles and stairways

Aisles and stairways should be clearly marked and kept clear of objects that can cause

trips and falls. Aisles should be wide enough to accommodate people comfortably and

safely. Warning signs and mirrors can improve sight lines at blind corners. Properly

arranged aisles encourage people to use them so that they do not take "shortcuts" or

"bottleneck" storage. Stairways and aisles also require adequate lighting.

10.5 Spill control

The best way to control spills is to stop them before they happen. Regularly cleaning

and maintaining machines and equipment is one way to do this. Another is to use drip

pans and guards where possible spills might occur. When spills do occur, it is important

to follow cleanup procedures as indicated on the Material Safety Data Sheet. Spills

must be cleaned up immediately. Absorbent material is useful for wiping up greasy, oily

or other liquid spills. Used absorbents must be disposed of properly and safely.

10.6 Tools and equipment

Keeping tools neat and orderly can be very important to everyone's safety, whether in

the tool room, on the rack, in the yard, or on the bench. Returning tools promptly after

use reduces the chance of them being misplaced or lost. Workers should regularly

inspect, clean and repair all tools and take any damaged or worn tools out of service.

10.7 Maintenance

A good maintenance program provides for the inspection, maintenance, upkeep and

repair of tools, equipment, machines and processes. Maintenance involves keeping

buildings, equipment and machinery in safe efficient working order and in good repair.

This includes maintaining sanitary facilities and regularly painting and cleaning walls,

maintaining windows, damaged doors, defective plumbing and broken floor surfaces.

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10.8 Waste disposal

The regular collection, grading and sorting of scrap contributes to good housekeeping

practices. Allowing materials to build up on the floor wastes time and energy since

additional time is required for cleaning it up. Placing scrap containers near where the

waste is produced encourages orderly waste disposal and makes collection easier. All

waste receptacles should be clearly labeled (e.g., recyclable glass, plastic, metal, toxic

and flammable etc.) All waste containers should be emptied regularly.

10.9 Storage

Stored materials should allow at least one meter (or about 3 feet) of clear space under

sprinkler heads. Stacking cartons and drums on a firm foundation and cross tying them,

where necessary reduces the chance of their movement. Stored materials should not

obstruct aisles, stairs, exits, fire equipment, emergency eyewash fountains, emergency

showers, or first aid stations. All storage areas should be clearly marked by fire

prevention: flammable, combustible, toxic and other hazardous materials should be

stored in approved containers in designated areas that are appropriate for the different

hazards that they pose. All combustible and flammable material must be present only in

the quantities needed for the job and kept in safety cans during use. Oily or greasy rags

should be placed in a metal container and disposed of regularly.

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Name…………………………………………… ID………………………… Date…….




1. What are the objectives of maintaining the working area? (5 points)

2. List down the idea support`s best way to control spills before they happen?

(5 points)


Answer Sheet

Score = ___________

Rating: ____________


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Information Sheet 11 - Conducting work with environmental standards and

legislative requirements

11.1 Introduction

Grain can be processed in many different ways depending on the type of raw material

and the end product. The techniques most frequently used are:

Milling to reduce grain to smaller particles including flour;

Malting by germinating seeds; and

Extracting soluble carbohydrates for brewing.

Most by-products are dry and environmentally benign. The manufacturing steps include

some or all of the following as indicated in the below diagram (Figure 1). At all

manufacturing step there is a possibility of key environmental, health and safety

risk/liability issues. They are product contamination, dust and aerosols, wastewater

discharge, solid Waste, etc. Therefore, following the environmental protection policy and

regulation for reducing sources of environmental risks is must.

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Figure1. Grain mill operation process

11.2 Fire and explosion risk reduction

Use all dust emission reduction techniques;

Improved removal of metal, stones and glass which can cause sparking;

Locate equipment within a lightweight building so that the roof and wall

cladding panels can act as explosion relief;

Fit silos and bins with explosion relief;

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11.3 Reduction of spoil and loss

Weather proofing windows, doors and other openings against pests and

water;

Controlling moisture content in grain storage;

Monitor product losses during processing operations;

Ensure organic waste is collected and stored separately from other waste to

enable composting and/or use for soil amendment, or use in energy

production;

Regular inspection should be carried out of all bulk containment on site to

prevent leakage and product loss;

Provision of secondary spill containment for storage and process vessels;

Select cleaning materials that do not have an adverse effect on the

environment;

Good housekeeping should be maintained at all times all areas.

The adoption of good cleaning and working practises as a routine will reduce

dour emissions and improve hygiene standards;

Provision of personal protective equipment (PPE) that is fit for the task to

prevent injury and maintain hygiene standards. Staff should be trained in the

correct selection, use and maintenance of PPE;

Train workers in correct use of machinery and safety devices;

Redesign manual processes to avoid heavy lifting/repetitive activities;

Install mechanical lifting aids where possible and rotate work tasks to reduce

repetitive activities;

11.4 People separation from moving equipment

Ensure that the process layout reduces opportunities for process activities

to cross paths;

Installation of safeguards on moving parts of conveyor belts and

packaging machinery to reduce risk of entrapment of employees;

Install walkways to separate people from vehicle movements to reduce

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risk of collision;

11.5 Social, Labor and Community Improvements

Implement a quality control plan including sampling procedures and

frequencies;

Analysis methods;

Destination of non-compliant product;

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Name…………………………………………… ID………………………… Date…….




1. List down the techniques most frequently used in grain processing activity. (5

points)

2. Choose only three dust emission reduction means, then explain. (5 points)


Answer Sheet

Score = ___________

Rating: ____________


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Information Sheet 12 - Maintaining workplace records requirements

12.1 Introduction

Every employer covered by the Fair Labor Standards Act (FLSA) must keep certain

records for each covered work, exempt and nonexempt worker. Apart from the legal

implications, maintaining accurate and updated employee records helps employers

save time while performing administrative duties. These details can also come in handy

during the recruitment process, identifying gaps in skills, availability of resources or at

the time of separation. Everyone wants to stay organized as well as to increase

productivity at workplace or in office.

12.2 Records to be kept by employers

There is no required form for the records, but the records must include accurate

information about the employee and data about the hours worked and the wages

earned. The following is a listing of the basic records that an employer must maintain:

Employee's full name and social security number;

Address, including zip code;

Birth date, if younger than 19;

Sex and occupation;

Time and day of week when employee's workweek begins. Hours worked

each day and total hours worked each workweek.

Basis on which employee's wages are paid;

Regular hourly pay rate;

Total daily or weekly straight-time earnings;

Total overtime earnings for the workweek;

Overtime: Covered nonexempt employees must receive overtime pay for

hours worked over 40 per workweek.

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Hours Worked: Hours worked ordinarily include all the time during which

an employee is required to be on the employer’s premises, on duty, or at a

prescribed workplace.

Recordkeeping: Employers must display an official poster outlining the

requirements of the FLSA. Employers must also keep employee time and

pay records.

Child Labor: These provisions are designed to protect the educational

opportunities of minors and prohibit their employment in jobs and under

conditions detrimental to their health or well-being.

12.3 Enterprise coverage

Employees who work for certain businesses or organizations (or "enterprises") are

covered by the organization for which they are working. Even when there is no

enterprise coverage, employees are protected by the Fair Labor Standards Act

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Name…………………………………………… ID………………………… Date…….




1. What is the importance of maintaining work place records? (5 points)

2. Which one of the following records is to be kept by employers? (5 points)

A. Employee’s full name and social security number,

B. Sex and occupation and Regular hourly pay rate,

C. Time and day of week when employee's workweek begins,

D. Basis on which employee's wages are paid,

E. All.


Answer Sheet

Score = ___________

Rating: ____________


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Operation Sheet 1- procedure for grinding the bore of a bushing

The following sequence is provided step-by-step for grinding the bore of a bushing in

order to attain correct procedure, follow these procedures.

Step-by-step procedure for grinding the bore of a bushing

Bolt internal grinding attachment to the wheel head on the universal tool and

cutter grinder.

Set up the workpiece in an independent chuck and check and adjust its

alignment, to rotate in the direction opposite that of the grinding wheel.

Mount the internal grinding attachment to the wheel head and adjust its position

so that the grinding wheel is centered vertically with the mounted workpiece.

True and dress the grinding wheel.

If two or more grinding wheels are used to complete internal grinding, true each

wheel after mounting it to the spindle of the internal grinding attachment.

Set the proper wheel speed on the grinding machine by adjusting the pulleys

and belts connecting the wheel spindle to the drive motor shaft.

The RPM is increased by placing a large pulley on the motor and a small pulley

on the attachment.

Set the proper rotational work feed. The speed should be 60 to 100 surface feet

per minute (SFPM).

Be sure sufficient clearance is allowed when setting the traversing speed so that the

grinding wheel will not strike any part of the workpiece or setup when the wheel is fed

into and retracted from the workpiece

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Operation Sheet 2- Steps of using cleaning hose and wet cleaning process.

Steps of using cleaning hose and wet cleaning process.

2.7 Safe operating procedures

Housekeeping

Do not:

Operate in poorly lit area.

Attempt to clear an auger while it is running.

Remove any covers or guards while the plant is running.

Allow children or inexperienced people to operate plant.

Allow spilt materials to accumulate near electric motors. Remove spilt

grain and dust as soon as the

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Operation Sheet 3- Reduction means of dust emissions

11.6 Means of dust emissions reduction

Enclosing and sealing plant and equipment to prevent escape and

accumulation of dust;

Use of doors/plastic strip curtains on building access points.

Redesigning processes to reduce free-fall distances and speed of movement

for grain and other dry products

Installing windbreaks and covers in outside handling areas;

Replace any external bulk storage areas with silos, fitted with alarms to

prevent overfilling;

Install a centralized piped vacuum cleaning systems;


Name----------------------------------- ID------------------------ Date--------------------------------

Time started: ________________________ Time finished: ________________

Instructions: Given necessary templates, tools and materials you are required to

perform the following tasks within 1 hour. The project is expecting you

to do it.

During your work: You can ask all the necessary tools and equipment

Lap Test Title: Produce Tool Shanks for Milling Machines

Task Objectives / Demands: in accomplishing activities required for this project the

student will be able to: (During your work follow these steps)


1 Apply procedure for grinding the bore of a bushing.

2 Perform steps of using cleaning hose and wet cleaning process.

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3 Determine reduction means of dust emissions.

LG #26 LO #3- Shut down the milling and purification process

Instruction sheet

This learning guide is developed to provide you the necessary information regarding

the following content coverage and topics:

Identifying shutdown procedures

Shut down process with workplace procedures.

Identifying and reporting maintenance requirements are



Identify shutdown procedures

Shut down process with workplace procedures.

Identify and report maintenance requirements are








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Information Sheet 1- Identify shutdown procedures

1.1 Introduction

The actions required by this procedure are essential to assure a safe shutdown and to

properly plan and allocate resources. Two types of utility shutdown are available. They

are emergency shutdowns and formal shutdowns.

1.2 Shutdown work identification

The work, which is to be carried, should be clearly identified. The work identification

depends upon following points:

The number of failures

The root causes of those failures

The maintenance costs associated with those failures

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The production costs associated with those failures - note that these may

incorporate more than just downtime costs.

Any safety or environmental implications associated with those failures.

1.2.1 Procedure for emergency shutdowns

Emergency shutdowns shall be done as follows:

The first responder shall immediately get him/herself and others out of harm’s

way, call the fire department or police if necessary. Notify the central call-in

desk, and begin taking whatever actions are necessary to mitigate damages.

If the first responder wasn’t the building Engineer the central call-in desk will

dispatch the building engineer to the scene.

For shutdowns within utility plants or in the central distribution, the ranking

person present shall assume authority. For shutdowns within buildings other

than utility plants, the ranking person present shall assume authority. The

only exception is if the shutdown requires a fire department or police

response, an on-scene incident commander shall assume authority. The

person who assumes authority shall direct all actions to eliminate the

immediate risk. All factory employees shall cooperate with and assist the

person having authority.

The person in charge is authorized to call in additional factory employees if

he/she deems it necessary to protect the facilities and/or the occupants work.

When the immediate risk has been controlled, the person who lead the

shutdown effort shall immediately notify his/her supervisor.

The supervisor shall designate responsibilities for clean-up or other activities

that need to continue and shall report the incident to the next level supervisor

and to Directors or Division of Environmental Protection (DEP). These

reports will either be done immediately or if the shutdown was done outside

normal business hours and no immediate hazard exists, the report can be

done first thing on the next business day.

The incident shall be reported up the chain of command to the chiefs. The

applicable branch chief will assume, or designate somebody else to assume

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authority for follow-up work and the authority will involve all other necessary

persons and/or groups in resolving the situation which created the

emergency.

Within one business day, the applicable branch chief shall notify the director,

the situation including cause, action taken, damage and current status.

1.2.2 Procedures for formal shutdowns

All formal utility shutdown requests shall be electronically routed to a queue and shall be

pulled from the queue by the responsible personnel. The person who pulls the queue is

responsible for evaluation of the queue, notification of the facility users, planning,

communication with the responsible section, facility manager and others and in general

identifying and doing or delegating and managing whatever tasks are necessary to

make the shutdown run smoothly. The responsible person shall identify and implement

(delegate, manage or provide oversight on) any unique requirements. The responsible

person may request that to manage the implementation of a unique requirement. For

example, the chief person may request that the person who arrange for temporary

services to the affected area so the critical functions can continue uninterrupted.

1.2.3 Procedure for minor formal shutdowns

The responsible person shall discuss the shutdown with the building

engineer before submitting it and both will have agreed that the shutdown

is minor. Request shall be submitted through the shutdown webpage no

less than two working days in advance and shall be in the “approved”

status for no less than one day.

When a request is entered at the webpage, it goes into a queue. All

shutdown requests that are labeled as minor shall be taken from the

shutdown queue by building maintenance within a day.

1.2.4 Procedure for major formal shutdowns

The project officer shall submit shutdown requests through the shutdown

webpage no less than 18 calendar days in advance. The request shall be

in “approved” status for no less than 14 days.

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For any work involving underground utilities, the project officer shall

discuss the project with the Director of the Central Systems Team and the

Director shall assign a contact person for the project. Whenever

considering an underground utilities shutdown, the project officer must

discuss the shutdown with the contact person before submitting the

request. The Central Systems Team contact person shall begin

scheduling underground utility shutdowns after discussing with the project

officer. The Building Maintenance Team shall notify the Central Systems

Team when the request has been received electronically.

For all major formal shutdowns, upon entry in the web based system, the

system will automatically put the request in “submitted” status and move it

to a queue. Support Services Team (SST) within the maintenance

services branch shall pull all fire alarm and sprinkler requests from the

queue for processing. Building Maintenance Team shall pull all other

request. Building Maintenance shall coordinate with the Utilities

Operations Branch for underground utilities shutdowns. Whichever

shutdown group pulls the request shall plan the shutdown and move the

request to the “approved” status no less than 14 days in advance of the

event. Each group shall have internal office procedures covering how


Name…………………………………………… ID………………………… Date…….




1. How many types of utility shutdowns do you know? Would you list down them

here? (5 points)

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2. Which one of the following actions is intimately related to emergency shutdowns?

(5 points)

A. The first responder shall immediately get him/herself and

others out of harm’s way.

B. Electronically routed to a queue.

C. Responsible person shall identify and implement any

unique requirements.

D. None.


Answer Sheet

Information Sheet 2- Shut down process with workplace procedures

2.1 Introduction

All requests for formal scheduled utility shutdowns shall be entered. A specific date

must be requested. Safe use shutdown process of machines (mill, ball, pedestal

grinding) are indicated here bellow.

2.2 Workshop machines – mill shutdown process

Keep all guards in place while operating the machine.

While operating the milling machine allow no one else to touch it.

Keep hands away from moving cutting tools.

Score = ___________

Rating: ____________


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Do not make measurements of the stock while the milling machine is

powered.

Do not allow large quantities of chips to accumulate around the work piece or

machine table. After stopping the machine, use a brush or rag to remove all

excess chips from the mill bed and stock.

Use a rag or Kevlar gloves to handle sharp cutting tools.

Cutting tools must be securely fastened in the machine spindle with the

proper accessory. Never try to tighten cutting bits or tools by hand.

Do not power the machine to tighten or loosen cutting bits or tools.

Work pieces and stock must be rigidly fastened to the mill bed with clamps, a

vise, or special fixtures.

Use appropriate speeds and feeds for the type and size of cutter being used

and the material being machined.

Make sure the cutting tool is clear of the work piece before starting the

machine.

2.3 Workshop machines - pedestal grinder shutdown process

Inspect the wheels before turning on the power. Do not use wheels that are

chipped or cracked.

Stand to one side of the wheel when turning on the power.

Keep the tool rest as close to the grinding wheel as possible without touching

it. The tool rest must be minimally within 1/8th of an inch of the grinding

wheel.

Prior to starting the grinder, ensure the tang at the top of the wheel opening is

located within ¼ inch of the wheel.

Prior to starting the grinder, ensure guards enclosing the outside of grinding

wheel are in place.

Prior to adjusting the work rest or tang, unplug the power to the grinder from

the wall receptacle.

If the grinder is hardwired into a box, Lock-out/Tag-out.

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Be alert and cautious when a grinding operation requires locating fingers

close to the wheel.

Feed the stock into the wheel with light to medium pressure. Do not force the

piece.

Do not use the side of the grinding wheel to shape stock.

Stand erect in front of the grinder with both legs straight and slightly apart.

Avoid stooping or leaning into the machine.

2.4 Normal shutdown sequence of mill and grinding circuit

Shut off cyanide metering pump.

Put weight controller into manual mode and turn controller output to 0%. Run

the ball mill for 15 – 30 minutes.

Put density controller into manual mode, set output to 0%.

Put flow controller into manual mode and set output to 0%

Turn off ball mill lime timer.

Disengage ball mill clutch. The mill conveyor will automatically stop due to the

interlocks between the clutches or cyclone feed pumps and the conveyer.

Shutdown ball mill motor.

Shutdown ball mill lube system.

Drain and flash the cyclone feed pump, line and pump box if the shutdown is

longer than 1-2 hours. Once the pump and system have been drained, shut

off the cyclone feed pumps and close the gland seal water shut off valve to

the cyclone feed pump.

Close the air block valves to the cyclones and the cyclone feed pump box,

and shut off valves on all barren lines.

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Name…………………………………………… ID………………………… Date…….



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1. Lists down the machines you had been observed their Safe use shutdown

process. Submit their diagram to your instructor too.

2. While operating the milling machine allow no one else to touch it. Discuss.


Answer Sheet

Score = ___________

Rating: ____________



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Information Sheet 3- Identifying and reporting maintenance requirements

3.1 Introduction

It is known that best practices for milling machine maintenance are lubrication, cleaning

and daily inspection. One way to keep tools for machine services in good condition is by

making sure that they are adequately lubricated. Another requirement for keeping a

piece of machinery usable is making sure that is properly cleaned after use. By keeping

up with daily inspections, you can prevent a problem from happening right from the get-

go.

3.2 Daily inspections

A daily inspection is especially important if you’re using your milling machine on a daily

basis. If something is amiss and you start using your machine without thoroughly

inspecting it first, you may be in for a world of trouble. If something looks fine one day

and operates wrong the next, an inspection can catch the issue before it’s too late. If

you find any problem with your tool but are unsure of how to fix it, reach out to your

machine shop immediately for the fix or other tips. But until then, make sure you’re

practicing good maintenance with all of your machine tools.

3.3 Maintenance recommendation

Maintenance recommendations are based on industry standards and experience in

reclamation facilities. However, equipment and situations vary greatly, and sound

engineering and management judgment must be exercised when applying these

recommendations. Other sources of information must be consulted (e.g., manufacturers

recommendations, unusual operating conditions, personal experience with the

equipment, etc.) in conjunction with these maintenance recommendations. Classifying

level of maintenance, while reporting for maintenance requirement, as here indicated

below, is highly useful.

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3.3.1 Preventive maintenance

Preventive maintenance (PM) is the practice of maintaining equipment on a regular

schedule based on elapsed time or meter readings. The intent of PM is to “prevent”

maintenance problems or failures before they take place by following routine and

comprehensive maintenance procedures. The goal is to achieve fewer, shorter, and

more predictable outages.

Some advantages of PM are:

It is predictable, making budgeting, planning, and resource leveling

possible.

When properly practiced, it generally prevents most major problems, thus

reducing

forced outages, “reactive maintenance,” and maintenance costs in

general.

It assures managers that equipment is being maintained.

It is easily understood and justified.

Preventive Maintenance does have some drawbacks:

It is time consuming and resource intensive.

It does not consider actual equipment condition when scheduling or

performing the maintenance.

It can cause problems in equipment in addition to solving them (e.g.,

damaging seals, stripping threads).

Despite these drawbacks, PM has proven generally reliable in the past and is still the

core of most maintenance programs.

3.3.2 Reliability-centered maintenance

Reliability-centered maintenance (RCM) programs are gaining in popularity and have

been piloted in a few reclamation power facilities with good results. The goal of these

programs is to provide the appropriate amount of maintenance at the right time to

prevent forced outages while at the same time eliminating unnecessary maintenance.

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Implemented properly, RCM can eliminate some of the drawbacks of PM and may result

in a more streamlined, efficient maintenance program. RCM seems very attractive in

times of diminishing funding, scarcity of skilled maintenance staff, and the pressure to

“stay online” due to electric utility industry deregulation.

Some features of RCM are:

It may be labor intensive and time consuming to set up initially.

It may require additional monitoring of quantities, like temperature and

vibration, to be effective. This may mean new monitoring equipment with

its own PM or more human monitoring with multiple inspections.

It may result in a “run-to-failure” or deferred maintenance philosophy for

some equipment which may cause concern for some staff and managers.

It may require initial and later revisions to the maintenance schedule in a

“trial-and-error” fashion depending on the success of the initial

maintenance schedule and equipment condition.

It should result in a more manageable maintenance workload focused on

the most important equipment.

RCM is not an excuse to move to a “breakdown maintenance” philosophy or to

eliminate critical PM in the name of reducing maintenance staff/ funding.

3.3.3 Condition-based maintenance

This program relies on knowing the condition of individual pieces of equipment.

Some features of condition based maintenance (CBM) include:

Monitoring equipment parameters such as temperatures, pressures,

vibrations, leakage current, dissolved gas analysis, etc.

Testing on a periodic basis and/or when problems are suspected such as

Doble testing, vibration testing, and infrared scanning.

Monitoring carefully operator-gathered data.

Securing results in knowledgeable maintenance decisions which would

reduce overall costs by focusing only on equipment that really needs

attention.

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Drawbacks to CBM include it being very difficult and expensive to monitor some

quantities. It requires knowledgeable and consistent analysis to be effective; and also

condition monitoring equipment and systems themselves require maintenance. Because

of these drawbacks, it is nearly impossible to have an entirely CBM program.

3.3.4 Combination of condition-based and preventive maintenance

A combination of CBM and PM is perhaps the most practical approach. Monitoring,

testing, and using historical data and PM schedules may provide the best information on

when equipment should be maintained. By keeping accurate records of the “as found”

condition of equipment when it is torn down for maintenance, one can determine what

maintenance was really necessary. In this manner, maintenance schedules can be

lengthened or perhaps shortened, based on experience and monitoring.

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Table 1. Pre and after maintenance requesting and reporting format, respectively

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Name…………………………………………… ID………………………… Date…….



Test I: Choose the best answer

1. Which one of the following level of maintenance is time consuming and resource

intensive?

A. Condition-based maintenance

B. Preventive maintenance

C. Reliability-centered maintenance

D. None

2. A _______________ is especially important if you’re using your milling machine

on a daily basis.




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Reference Materials

Book:

1. Erik Oberg, Franklin D. Jones, Holbrook L. Horton, and Henry H. Ryffel,

“Machinery’s Handbook”, 27th Edition, Industrial Press, Inc., New York, NY, 2004

2. Helmi A. Youssef and Hassen El-Hofy, “Machining technology, Machine tools

and operations”, Taylor & Francis Group, Boca Raton, London, New York, 2008

3. Fundamentals of machine tools, Training Circular No. 9-524, headquarters

department of the army, Washington, DC, 29 October 1996

4. Shafizan Bt. Shariffuddin School of Manufacturing Engineering UniMAP

5. Inspection of Metals—Understanding the Basics, Copyright © 2013 ASM

International F.C. Campbell, editor, All rights reserved www.asminternational.org

6. Machining and Machine Tools by A. B. Chattopadhyay.

7. Metal Cutting: Theory and Practice by A. Bhattacharya.

8. Adams, M. & Moss, M. 2008, ‘Microbiology of primary food commodities’, in Food

Microbiology, 3rd edition, pp. 119-157

9. Bullerman, L.B. & Bianchini, A. 2011, ‘The microbiology of cereals and cereal

products’, Food Quality & Safety Magazine, February/March.

WEB ADDRESSES

1. ISO 9000:2005 Quality Management System – Fundamentals and Vocabulary

2. http://www.qualitygurus.com/courses/mod/forum/discuss.php?d=1557

3. http://www.iitg.ac.in/spal/Methods%20of%20mounting%20of%20jobs%20and%20c

utting%20tools.ppt

4. http://www.iitb.ac.in/safety/sites/default/files/Machine%20Safety_0_0.pdf)

5. https://www.fda.gov/media/109408/download

6. https://www.flexiblemachining.com/pdf/quality_policy.pdf

7. file:///C:/Users/pc/Desktop/SNE%20Post%20harvest%20Curricul%20OMP/Cereals

%20POST-HARVESTING%20PROCESSING.pdf

8. https://productionengineering08.blogspot.com/2008/08/5-basic-milling-

operations.html

9. Marleeta F. Basey, 2015. Choosing the Right Countertop Grain Mill

http://www.asminternational.org/

http://www.qualitygurus.com/courses/mod/forum/discuss.php?d=1557

http://www.iitg.ac.in/spal/Methods%20of%20mounting%20of%20jobs%20and%20cutting%20tools.ppt

http://www.iitg.ac.in/spal/Methods%20of%20mounting%20of%20jobs%20and%20cutting%20tools.ppt

http://www.iitb.ac.in/safety/sites/default/files/Machine%20Safety_0_0.pdf)

https://www.fda.gov/media/109408/download

https://www.flexiblemachining.com/pdf/quality_policy.pdf

https://productionengineering08.blogspot.com/2008/08/5-basic-milling-operations.html

https://productionengineering08.blogspot.com/2008/08/5-basic-milling-operations.html

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AKNOWLEDGEMENT

We wish to extend thanks and appreciation to the many representatives of TVET

instructors and respective industry experts who donated their time and expertise to the

development Teaching, Training and Learning Materials (TTLM)

We would like also to express our appreciation to the TVET instructors and respective

industry experts of Regional TVET Bureau, TVET College/ Institutes, Bishoftu

Management institute, BEAR II UNESCO project and Federal Technical and Vocational

Education and Training Agency (FTVET) who made contributions for the development

of this curriculum with required standards and quality possible. This Teaching, Training

and Learning Materials (TTLM) was developed on October 2020 at Bishoftu, bishoftu

management institute.

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The trainers who developed the learning guide

N

o

Name Qualifi

cation

Educational

background

Regio

n

College Mob.no E-mail

1 Shiferaw

Negassa

(Phd)

Phd Plant science

(BSc),

horticulture

(MSc),

agronomy and

crop

physiology(Phd)

Oromia Holeta

satellite

college

0911913680 [email protected]

2 Tesfaye

Mekuriyaw

B Food science

and technology

Addis

Ababa

Kolfe

industrial

college

0927785174 Tesfayemekuriyaw48@gmail

.com

3 Moti Taye A Plant science Oromia Bako

College


4 Adamu

Bekena

B Food

technology and

process

engineering

Addis

Ababa

Yeka

industrial

college


5 Fistum FTA

facilitator

cereal processing - dl.otvet.gov.et

Documents