operations management session 9 -qa,va,pm 2-12

7/28/2019 Operations Management Session 9 -QA,VA,PM 2-12

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OPERATIONS MANAGEMENT


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OPERATION MANAGEMENT

HR

PRODUCT

MATERIALS

SCHEDULING

FACILITIES

PLANNING

PROCESSES

LAYOUT


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Value Analysis


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Value Analysis

How to get more from less is the gist of Value Analysis

(improve product properties)

Materials Accelerate Production Processes

Reduce scrap

Reduce cost


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Value Analysis

Objective :

Improve the qualities of a product, while maintaining or

reducing its costs

Process :

> To find precisely the qualities/specification the product is supposedto possess and why?

> Compare these with materials and production operations, to relate

materials and operations responsible for each of the required

characteristics

> To reveal material qualities that are not exploited or operations that

seem duplicating or unnecessary.

> By critically examining and analysing the value of materials and

processes, new and efficient methods/materials may be explored


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Value Analysis

Need for Value Analysis:

> Designers reluctant to change techniques that have been repeatedly used

with success

Reasons,

- due to ignorance, lack of experience in diversified methods ofmanufacture

- Anxieties and uncertainties with change

- Installation of new methods/materials, accompanied by

unforeseeable difficulties, people have to adjust, lack of confidence,


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Value Analysis

Value analysis tests:

- Does its use contribute value?

- Is its cost proportionate to its usefulness?

- Does it need all its features?

- Is there anything better for the intended use?

- Can a usable part be made by a lower cost method?

- Is it made on proper tooling, considering quantities used?

- Do materilas, reasonable labour, overhead, and profit total its cost?

- Will another dependable supplier provide it for less?- Is anything buying it for less?


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Quality Control


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QUALITY CONTROL

Quality :

The development & realisation of specification necessary to produce

economically and in adequate degree, the appearance, efficiency,

interchangeability and life , which ensures the products present and

future markets. It is the total of features of a product or service that bear on its ability to

satisfy the stated or implied needs;

> Actual & perceived


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QUALITY CONTROL

Functions :

To satisfy the customer by endeavouring to comply with the declared

specs of the Product

To ensure that the work may proceed to the next operation

To be instructive, so that recurrence of mistake could be eliminated

To compare quality levels obtained with desirable level process control

for determination of trends & process adjustment procedures.

To determine the optional quality obtainable for available process and to

provide useful guides for specifications at Design stage.

To minimise scrap to an economical level.

To facilitate process of incentive payments.

To be able to identify faulty outputs with operations.

To evaluate existing inspection methods & design better/more effective

procedure.


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QUALITY CONTROL

Quality Objectives:

Definable:

- Physical dimensions

- Physical & Chemical properties of materials strength, weight,

composition etc.

For which:

- Design comparatively simple and quick testing techniques with which

these attributes can be measured

- Define good & bad acceptable and non acceptable


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QUALITY CONTROL

Quality Objectives:

Not Definable:

- Brightness, whiteness

- Surface textures

- Smell etc.

These are subjective and in some cases can be measured

indirectly , eg light, surface finish etc.


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QUALITY CONTROL

Total Quality Management:

> To excel on all dimensions of products & services that are

important to the customers.

> Quality must be ensured in all the areas:

> Marketing, design, purchase, production or operations &

distribution


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QUALITY CONTROL

Fundamental Goals:

- Careful design of the product or service

- Ensure the systems consistently produce the design specs/features

Quality of Design:

- Incorporates features & attributes that satisfy customer needs/expectations.

- Design quality is a major contributor for the value of the product in the market. Most

important feature of design with regard to quality is specification.

- Describes in a comprehensive statement of all its aspects which are needed to fulfil

the requirements.

- The maximum tolerable variation in the requirement/attribute should be defined.


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QUALITY CONTROL

Dimensions of design quality are:

> Performance , Primary operating characteristics

> Features , Influence perception of the customers

> Reliability, Failures within the specified time period

> Durability, Life of the Product

> Serviceability, ease with which product can be repaired/availability of standard

spares etc.

> Response, Speed to solve customers problems

> Aesthetics, to satisfy sensory needs- sound, look, feel, aroma, colour etc.

> Reputation, past performance, other intangibles


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QUALITY CONTROL

Service Quality:

> Timeliness

> Completeness

> Courtesy

> Consistency

> Accessibility and convenience


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QUALITY CONTROL

Cost of Quality:

Product to be made Right, the first time, every time

> To avoid defectives rather than repairing or replacements

> With an aim to prevent any additional costs

Costs associated with Quality:

> Failure Costs

> Prevention Costs


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QUALITY CONTROL

Failure Costs:

Relate to production below the quality standard, resulting into,

> Scrapping defective items

> Reworking defective items

> Re-inspecting

> Downgrading as seconds

> Wastage costs holding etc.

> Repairing and servicing after sales

> Warranty claims

> Complaints from customers

> Returned Products> Liabilities/litigations

> Loss of Goodwill

> Non payments/bad debts


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QUALITY CONTROL

Prevention Costs:

Costs associated with design, implementation and maintenance of quality system, to ensure

right, first time. These include:

> Product or Service requirements Determination of Quality requirements and laying

down specifications of incoming materials, processes, intermediateries and finished products

and services.

> Quality Planning & Assurance Creating systems & procedures to ensure quality

> Appraisal Equipment- Costs of designing and procuring instruments, tools and

accessories required to carry out quality appraisals.

> Training Development, preparation and conduct of Quality training programmes for

Operators, supervisors and managers.


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QUALITY CONTROL

Stages of Quality Control:

Inspection of incoming materials & bought out items

> Sample Inspection

> Process and Operation conditions at Vendors place to ensure that these

confirm to methods agreed upon.

Inspection of failures

First of Inspection

Inspection by self control

Final inspection

Post Sales Quality Evaluation/audit


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QUALITY CONTROL

Acceptance Sampling:

> Decisions based on comparatively small samples

> Helps saving costs/time/monotony

> Inspection with great care & reliable

> Involves risks, as sample taken is at Random and results may not be true

reflections of the lot.


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QUALITY CONTROL

Sampling Plan:

Two major factors in acceptance sampling are:

>Sample size

> Sampling plan ( no. of successive samples taken in the process)

Single Sampling Plan :

> One Sample of certain numbers

> Accept/Reject the lot

Double Sampling Plan:

> A sample is inspected & if defects below acceptable level Accept

> If defects level high, but within a second acceptance limit, take another sample

& if the results within acceptable limits for two lots combinedAccept

Multiple or Sequential Sampling plan:

> Similar to double sampling

> Repeated till decision comes out


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QUALITY CONTROL

Control Charts in SQC:

X bar & R Chart for process control:

To establish whether process is under Statistical Control, in which case variation is

attributed to chance.

Guides whether process capability is compatible with the specifications

Detects trends in the process, to help assist planning adjustments

To show when the process is out of control & make efforts to trace the causes.


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QUALITY CONTROL

Procedure:

Take a number of sample of components coming out of the process over a period of time,

each sample of units at random.

X bar = Average value of all measurements of a sample

R = Range ( highestlowest reading)

X double bar= Grand averageR bar = Average of all R

X bar chart

UCL Xbar= X double bar+A2 R

LCL X bar= X double barA2R

R Chart

UCL R= D4Rbar

LCL R = D3Rbar

Statistical Quality Control assumes normal distribution

As long as X bar and R values for each sample are within the limits, the process is said to be in

Statistical Control.


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QUALITY CONTROL

p- Chart:

- Fraction defective chart to control general quality of product & to ascertain whether

fluctuations are due to chance alone.

- Through determining Control Limits

- Whereas X bar & R charts are for measurable attributes/dimensions, p chart is for %

defectives, irrespective of causes of defectsGo/No Go

Control Limits:

UCL p = p + 3 sigma p

LCL p = p 3 sigma p

P is the desirable ratio

Sigma p is the standard deviation of the desirable ratio


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QUALITY CONTROL

C - Chart:

- For control of number of defects observed per unit

- In this case control limits are based on Poisson Distribution, which is often considered

desirable to describe distribution of defects

Control Limits:

UCL c = c + 3 sq. root cLCL c = c 3sq.root c

c = desirable level of number of defects/unit

sq.root c= standard deviation


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QUALITY CONTROL

Statistical Method of process control attempts to distinguish between

the two sources of variability:

> Inherent process variability

> Additionalexternal causes that result in consistent trends or shifts of mean value of

measured attribute.

The process is under Statistical Control, if the variability is confined to the inherent process

variations.


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Cost of Quality

Product to be made Right, the first time, every

time

To avoid defectives rather than repairing or

replacements

With an aim to prevent any additional costs

Costs associated with Quality:

Failure Costs

Prevention Costs


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Prevention Costs

Costs associated with design, implementation and maintenance of

quality system, to ensure right, first time. These include:

Product or Service requirements Determination of Quality requirements

and laying down specifications of incoming materials, processes,

intermediateries and finished products and services.

Quality Planning & Assurance Creating systems & procedures to ensure

quality

Appraisal Equipment- Costs of designing and procuring instruments, tools

and accessories required to carry out quality appraisals.

Training Development, preparation and conduct of Quality trainingprogrammes for Operators, supervisors and managers.


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Quality Control

Relationship between Costs of Quality and Organisational capability


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Statistical Quality Control Normal Curve


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Tools for identifying Quality Problems & Causes:

Check sheet

Appearance of common defects

No. Of occurrences

Histogram

Frequency of data related to a quality problem

Pareto Analysis % of defects occurring due to different causes to identify major quality problems

Flow Chart

Shows steps in process & identify where the problem may exist

Scatter Diagram

Graph shows relationship between two variables to help identify patterns that maycause quality problems

Statistical Quality Control Charts

Statistical UCL & LCL

Cause & Effect Diagram ( Herring Bone):

Represents causes & effects


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Statistical Quality Control

Histogram- indicates frequency of data related to a quality problem


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Pareto Analysis Chart- percentage of defects occurring due to different causes


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Flow chart Diagram showing steps in a process which helps identifying the stage

where problem exists


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Scatter Diagram A graph showing relationship between the two variables in a

process to identify patterns that may cause quality problems


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Cause and Effect Relationship:

In this case we try to diagrammatically establish relationships between

possible causes and their effects and work out solutions to limit the

causes to an extent that the effects do not bring the item beyondacceptable tolerances .


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Plant Maintenance

A key to successful execution of plans for

production in any organisation

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Plant Maintenance

Objectives:

> Maximisation of the performance of production

facilities production capacity

> Minimise loss or inconvenience caused by

unavoidable breakdowns> Improve reliability of equipment

> Maximise useful life of the equipment

> To keep equipment safe and prevent the

development of safety hazards

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Plant Maintenance

Maintenance policies:

Maintenance of facilities and equipment in good working

order is essential to achieve specified levels of quality and

reliability and efficient working- the best equipment will notwork satisfactorily unless it is cared for. The cost of the

breakdown in the system can be very high:

- Financial terms

- Poor morale- Customers dissatisfaction

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Plant Maintenance

Main causes of failure:

Weaknessunder normal stress of use, the product

may fail due to:

- Poor design

- Materials

- Workmanship

Misuse under application of stress outside the usual

capability of the product or service system

Pl M i


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Plant Maintenance

Types of Failures :Total failure: Complete lack of ability of the product or

service to perform the required functions.

Partial failure: Service not as well as expected

Gradual failure: Progressively over a period of time &

perhaps could be anticipated by some

kind of examination.

Sudden failure: Occurs quickly and is not easily

predictable.

Pl M i


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Plant Maintenance

Time of failure:

Maintenance work carried out before failure is

preventive maintenance.

Preventive maintenance l Breakdown maintenanceFailure

l..Time

A systematic preventive maintenance plan can reduce

breakdown & hence delay the time of failures

Pl M i


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Plant Maintenance

Preventive maintenance:- Attempts to eliminate or reduce chances of failures

by servicing (clearing, replacing, lubricating,

checking etc.) facilities at pre planned intervals

> Engine of an aircraft after certain flying hours.

- Preventive maintenance is planned in one of the following

ways:

Time based: Doing maintenance at regular intervals.

Work based: after set numbers of operating hours

e.g. Flying hours, no. of copies

Pl t M i t


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Plant Maintenance

Opportunity based:

- when equipment is available, holiday ( closure)

- Though can extend the maintenance cycle to an

unacceptable level

Condition based:- Relies on planned inspection to reveal

when maintenance is prudent.

- Replacement of break liner when thickness is

reduced to say 2mm.

Pl t M i t


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Plant Maintenance

Breakdown Maintenance:

- To carry out maintenance when equipment

fails:

- TV, Bathroom fittings, telephone

Pl t M i t


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Plant Maintenance

Maintenance Cost Balance:

- Most operations plan their maintenance to include a level of

regular preventive maintenance which gives a reasonably low but

finite chance of breakdowns.

- More frequent the preventive measures, the less probability

of breakdowns.

- The balance between preventive and breakdown maintenance

the total cost of breakdown infrequent preventive maintenance

will cost less but likely to result in more frequent breakdowns and

hence more cost of breakdowns.

Pl t M i t


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Plant Maintenance

- Frequent preventive maintenance will increase cost but

will reduce of having to provide breakdown

maintenance

- An optimal level of preventive maintenance is plannedto minimize total cost.

- To workout preventive maintenance policy for optimum

cost, we need to have data concerning breakdowns.

Pl t M i t


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Plant Maintenance

Total Productive Maintenance:- Improve equipment effectiveness

- Achieve autonomous maintenance;

- People take responsibilities for the

improvement of maintenance performance

at

- Repair level

- Prevention level

- Improvement level

Pl t M i t


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Plant Maintenance

Total Productive Maintenance:

- Planned Maintenance:

Have a completely planned maintenance routine, with level of preventive

maintenance for each equipment, the standards for condition based maintenance and

the responsibilities of operating & maintenance staff are included.

Maintenance Staff Operating Staff

Roles To develop To take on

- preventive actions - ownership of facilities

- breakdown actions - care of facilities

Responsibilities - Train operators - Correct action

- Device maintenance - Routine preventive maintenance

practice

- Problem solving - Routine condition based maintenance

- Assess operating

practice

Pl t M i t


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Plant Maintenance

Total Productive Maintenance:

- Training of staff in relevant maintenance skills.

- Achieve early equipment management.

> Maintenance prevention traces all potential

problems back to their route cause, tries to

eliminate at that point

Plant Maintenance


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Plant Maintenance

Predictive maintenance:- Through experience and plant preventive

maintenance, it is generally possible to predict

failures/breakdowns and take actions to avoid

before breakdown occurs,

> Costly

> Reduces down time

Plant Maintenance


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Plant Maintenance

Maintenance staff:- Highly skilled

- Dedicated with 24/7 availability

- Teamwork

operations management session 9 -qa,va,pm 2-12

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