Flexible Manufacturing SystemsGroup 25

Metal forming

Metal-cutting

machines

Assembly

Joining-welding, gluing

Inspection

Surface treatmen

tTesting

Weaving looms with paper tapes

NC machines with paper tapes

Hard wired NC machines

Computer controlled NC

machines (CNC)

Direct Numerical Control (DNC)

USES

HIS

TO

RY

Understanding FMS Flexible automation where a group of processing workstations

(usually CNC machine tools) are linked together by a material handling system, all aspects of which are controlled by a distributed computer system.

Features

Processes more than one product style independently

Each machine in the system may process a

different part type

Changes can be made in the production schedule

to meet demands on different products

New product styles can be introduced into

production

Distinguishing Characteristic

s

Machines in the system are linked by an

automatic machine handling subsystems

Automatic continuous cycling of machines

Complete control of the manufacturing system by

the host computer

Lightly manned/unmanned

Part variety testPart variety testSchedule changetestSchedule changetest

Error recovery testError recovery test

The range of operations and part styles Basic Flexibilities Basic Flexibilities

Machine flexibility

Material handling flexibility

Expansion flexibility

Product flexibility

Volume flexibility System Flexibilities System Flexibilities

Program Flexibility

Production Flexibility

Aggregate Flexibilities Aggregate Flexibilities

New part testNew part test

Tests of Manufacturing Flexibility

Ease and precision of Material Transport

Ability to produce parts in high and low quantitiesEase with which the system can be Expanded to increase total productionEase with which new products can beintroduced

Ease of generating programs for new machine sequencesThe range or universe of part styles that Can be produced on the system

Types and Tests of Manufacturing Flexibility

Distinguishing FMS based on the number of Machines Single machine cell (Type I A)

A single machine cell consists of one CNC machining center combined with a parts storage system for unattended operation.

Completed parts are periodically unloaded from the parts storage unit, and raw work parts are loaded into it

Flexible manufacturing cell (usually type II A, sometimes type III A)

A flexible manufacturing cell consists of two or three processing workstations (typically CNC machining centers) plus a part handling system.

The part handling system is connected to a load/unload station. Flexible manufacturing system (usually type II A, sometimes type III A)

A flexible manufacturing system has four or more processing workstations connected mechanically by a common part handling system and electronically by a distributed computer system.

Levels of flexibility

Dedicated FMS

•Designed to produce a limited variety of part styles

•Complete universe of parts to be made on the system is known in advance

Random-

order FMS

•Part family is large•Substantial variations in part configurations •New part designs introduced into the system and engineering changes in parts currently produced

•Production schedule is subjected to change from day-to-day

Components of FMS1. Workstations

Load/Unload Stations; Machining Stations; Other processing Stations- Punching, shearing, welding; Assembly Station

2. Material handling and storage systems

Primary handling system establishes the basic layout of the FMS and is responsible for moving work parts between stations in the system

Secondary handling system consists of transfer devices, automatic pallet changing, and similar mechanisms located at the workstations

3. Computer control system uses a distributed computer system that

is interfaced with all workstations in the system, as well as with the material handling system and other hardware components

4. People required to manage and operate the

system – Basic setup, maintenance

1

2

3

4

FMS in real life Chrysler's Toluca plant, where the

PT Cruiser and Dodge Journey are made interchangeably, though they share few parts

The way this works is by extensive use of robots and computers; the robots have tooling or spot welders on the end of their "arms" and when a new vehicle comes down the line, they can quickly swap to different tooling or welders, and apply their arms in different ways

This also works in the paint shops, where robot arms are programmed to act differently depending on the vehicle that shows up

Employees at Chrysler Group LLCs �Toluca (Mexico) Assembly Plant marry the engine with the body of an all-new Fiat 500

A robot tightens the lug nuts on the wheel on the all-new Fiat 500 

Advantages of FMS

• Reduced work in process • Increased machine

utilization • Better management

control • Reduced direct and

indirect labor • Reduced manufacturing

lead-time • Consistent and better

quality• Reduced inventory

Disadvantages of FMS

• Expensive, costing millions of dollars

• Substantial pre-planning activity

• Limited ability to adapt to changes in product

• Technological problems of exact component positioning and precise timing necessary to process a component.

• Benefit of employee suggestion lost

See FMS at work!

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