Definition: The movement, storage, protection and control of

materials throughout the manufacturing and distribution

process including their consumption and disposal.

Handling of materials must be performed

Safely

Efficiently

At low cost

In a timely manner

Accurately (the right materials in the right quantities to the

right locations)

And without damage to the materials

Material Handling equipment includes:

1. Material transport equipment - to move materials inside afactory, warehouse or other facility

2. Storage - to store materials and provide access to thosematerials when required

3. Unitizing equipment - refers to (1) Containers to holdmaterials, and (2) Equipment used to load and packagethe containers

4. Identification and tracking systems - to identify and keeptrack of the materials being moved and stored- Mostcommon label used bar code readers

Material characteristics – For Example: If the material is liquid,

move long distance in great volumes then pipeline is the

appropriate transport.

Flow rate, routing and scheduling

Plant layout

Unit load principle

Material characteristics affect type of transport and storage

equipment required

◦ Solid, liquid or gas

◦ Size

◦ Weight

◦ Shape - long, flat, bulky

◦ Condition - hot, cold, wet, dirty

◦ Risk of damage - fragile, brittle, sturdy

◦ Safety risk - explosive, flammable, toxic, corrosive

Flow rate - amount of material moved per unit time

◦ Examples: pieces/hr, pallet loads/hr, tons/hr

◦ Whether the material must be moved in individual units, as

batches or continuously (pipe line).

Routing - pick-up and drop-off locations, move

distances, routing variations, conditions along the route

(surface, traffic, elevation)

Scheduling - timing of each delivery

◦ Prompt delivery when required

◦ Use of buffer stocks to mitigate against late deliveries

Material handling equipment considerations must be included in

the plant layout design problem

Correlation between layout type and material handling

equipment:

Plant layout type Material handling equipment

Fixed-position Cranes, hoists, industrial trucks

Process Hand trucks, forklift trucks, AGVs

Product Conveyors for product flow

Trucks to deliver parts to stations

In general, the unit load should be as large as practical for the

material handling system that will move and store it

A unit load is the mass that is to be moved or otherwise

handled at one time

Reasons for using unit loads in material handling:

◦ Multiple items handled simultaneously

◦ Required number of trips is reduced

◦ Loading/unloading times are reduced

◦ Product damage is decreased

(a) Wooden pallet (b) pallet box (c) tote box

Five categories:

Industrial trucks

Automated guided vehicles

Monorails and other rail guided vehicles

Conveyors

Cranes and hoists

Two basic categories:

Non-powered

Human workers push or pull loads

Powered

Self-propelled, guided or driven by human

Common example: forklift truck

(a) Two-wheel hand truck, (b) four-wheel dolly, (c) hand-

operated low-lift pallet truck

Wheeled forks insert into pallet openings

No provision for riding; truck is steered by worker usingcontrol handle at front of vehicle

Widely used in factories and

warehouses because pallet

loads are so common

Capacities from 450 kg

(1000 lb) up to 4500 kg

(10,000 lb)

Power sources include on-

board batteries and internal

combustion motors

Designed to pull one or more trailing carts in factories andwarehouses, as well as for airport baggage handling

Powered by on-board batteries or IC engines

An Automated Guided Vehicle System (AGVS) is a material

handling system that uses independently operated, self-propelled

vehicles guided along defined pathways in the facility floor.

Types of AGV:

Driverless trains

Pallet trucks

Unit load AGVs

First type of AGVS tobe introduced around1954 and still widelyused today.

Common application ismoving heavy payloadsover long distances inwarehouses andfactories withoutintermediate stopsalong the route

Used to move palletized loads

along predetermined routes

Vehicle is backed into loaded

pallet by worker; pallet is then

elevated from floor

Worker drives pallet truck to

AGV guide path and programs

destination and the vehicle

proceed automatically to the

destination for unloading.

Used to move unit loads from station to station

Often equipped for automatic loading/unloading of pallets andtote pans using roller conveyors, moving belts, or mechanizedlift platforms

I. Driverless train operations - movement of large quantities ofmaterial over long distances

II. Storage and distribution - movement of pallet loads betweenshipping/receiving docks and storage racks

III. Assembly line operations - movement of car bodies and majorsubassemblies (motors) through the assembly stations

IV. Flexible manufacturing systems - movement of work partsbetween machine tools

V. Miscellaneous - mail delivery and hospital supplies

Two aspects of vehicle management:

Traffic control - to minimize interference between

vehicles and prevent collisions. Two methods in traffic

control used in commercial AVGS systems are:

Forward (on-board vehicle) sensing: When a on-board

sensor detects an obstacle in front of it, the vehicle stop. When

obstacle remove the vehicle proceed.

Zone control: Divided in to separate zone, and the operating

rule is that no vehicle is permitted to enter the zone if that

zone is already occupied by an other vehicle.

Zone control to implement blocking system. Zones A, B, and D

are blocked. Zone C is free. Vehicle 2 is blocked from entering

Zone A by vehicle 1. Vehicle 3 is free to enter Zone C.

Travel velocity of AGV is slower than typical walking speed of human

worker

Automatic stopping of vehicle if it strays from guide path

◦ Acquisition distance

Obstacle detection system in forward direction

◦ Use of ultrasonic sensors common

Emergency bumper - brakes vehicle when contact is made with forward

object

Warning lights (blinking or rotating red lights)

Warning sounds of approaching vehicles

Self-propelled vehicles that ride on a fixed-rail system

Vehicles operate independently and are driven by electric motors

that pick up power from an electrified rail

Fixed rail system

◦ Overhead monorail - suspended overhead from the ceiling

◦ On-floor - parallel fixed rails, tracks generally protrude up

from the floor

Routing variations are possible: switches, turntables, and other

special track sections

Large family of material transport equipment designed

to move materials over fixed paths, usually in large

quantities or volumes

1. Non-powered

◦ Materials moved by human workers who push the load

along fixed path.

2. Powered

◦ Power mechanism for transporting materials is contained

in the fixed path, using chains, belts, rollers or other

mechanical devices

Roller

Skate-wheel

Belt

In-floor towline

Overhead trolley conveyor

Cart-on-track conveyor

Pathway consists of a series of rollers that are perpendicular to direction of travel

Loads must possess a flat bottom to span several rollers

Powered rollers rotate to drive the loads forward

Un-powered roller conveyors also available

Similar in operation to

roller conveyor but use

skate wheels instead of

rollers

Lighter weight and

unpowered

Sometimes built as

portable units that can be

used for loading and

unloading truck trailers in

shipping and receiving

Continuous loop with forward path to move loads

Belt is made of reinforced elastomer

Support slider or rollers used to support forward loop

Two common forms:◦ Flat belt (shown)◦ V-shaped for bulk

materials

(Support frame not shown)

Four-wheel carts powered by

moving chains or cables in

trenches in the floor

Carts use steel pins (or

grippers) to project below

floor level and engage the

chain (or pulley) for towing

This allows the carts to be

disengaged from towline for

loading and unloading

A trolley is a wheeled

carriage running on an

overhead track from which

loads can be suspended

Trolleys are connected and

moved by a chain or cable

that forms a complete loop

Often used to move parts

and assemblies between

major production areas

Handling devices for lifting, lowering and transporting

materials, often as heavy loads

Cranes

◦ Used for horizontal movement of materials

Hoists

◦ Used for vertical lifting of materials

Cranes usually include hoists so that the crane-and-hoist

combination provides

◦ Horizontal transport

◦ Vertical lifting and lowering

Hoist with mechanical

advantage of four:

(a) sketch of the hoist

(b) diagram to illustrate

mechanical advantage

(a) (b)

A half-gantry crane

Analysis of vehicle-based systems

◦ From-to charts and network diagrams

◦ Types of systems: industrial trucks, AGVS, rail-guided vehicles,

and asynchronous conveyor operations

Conveyor analysis

◦ Single-direction conveyors

◦ Closed loop conveyors

◦ Recalculating conveyor systems

From-To chart showing Flow rates between stations in a layout

• Value before the slash mark is loads/hr

• Value after the slash mark is travel distance

Analysis of vehicle-based systems

TC Considered an idle value because Its ignores any time losses.

The possible time losses:

1. Availability

2. Traffic congestion

3. Efficiency of Manual drivers

Availability (A) is determine by breakdown or being repaired time

Consider these factor the available time per hour per vehicle as 60

mint adjusted is

AT= 60 A Tf E

A= Availability , E = Efficiency

Traffic factor = Tf

Then the rate of delivery per vehicle is given by

Problem# An automated guided vehicle system has an average travel

distance per delivery=200 m and an average empty travel distance =150

m. Load and unload times are each 24s and speed of the AVG = 1m/s.

Traffic factor =0.9. How many vehicles are needed to satisfy a delivery

requirement of 30 del/hr? Assume A=0.95.