plant lay types

8/7/2019 Plant Lay Types

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2.008 -Spring 2004 2

Outline

1. Manufacturing Systems

2. Types of Plant Layouts

3. Production Rates

4. Design and Operations


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2.008 -Spring 2004 3

Manufacture

Market

Research

Conceptual

Design

Design for

Manufacture

Unit

Manufacturing

ProcessesAssembly

and Joining

Factory,

Systems &

Enterprise


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2.008 -Spring 2004 5

Time spectrum of Typical Activities in a

Manufacturing OrganizationSeconds Period Activity

108 DecadePlant design, Machine Selection,

107 Year System Simulation

Process design: CAD106 Month Catalogs

Select manufacturing methodsWeek

105 DayFactory Operation

104 Ship-ReceiveHour Transport Inventory

103

102

Minute Part handling101 Load/Unload

Assembly1 Second

.1 Machine controlCNC-DNC

.01 Adaptive control

Intelligent machines.001 Millisecond Process control


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2.008 -Spring 2004 6

How Man, Machine, and Material Spend

Time in the Factory

People Materials Machines

Value-added

Value-added

Value-added

Waste Waste Waste

Waste: transportation, storage,

inspect on and rework"Waste": unnecessary

movement of machine, setup

time, machine breakdown,

unproductive maintenance,

producing defective products,

producing products when not

needed, etc.

"Waste": waiting for materials,

watching machine running,

producing defects, looking for

tools, fixing machine

breakdowns, producing

unnecessary items, etc


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2.008 -Spring 2004 7

Disruptions/Variation

(Random Events)

Machine failure

Set-up change

Operator absence

Starvation/Blockage

Demand change


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2.008 -Spring 2004 8

Types of Plant Layout

Job Shop

Project Shop

Flow Line

Transfer Line

Cellular System


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2.008 -Spring 2004 9

Job Shop

Machines/Resources

are grouped according

to the process they

perform

Raw Material

Ready part

A A

A A

D D

D D

D D

C C

C C

C C


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2.008 -Spring 2004 10

Project Shop

Machines/Resources

are brought to and

removed from

stationary part as

required

A

A

C

B

B

D

DD

Raw

material/

Ready part


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2.008 -Spring 2004 11

Flow Line and Transfer Line

Machines/Resources

are grouped in lines

according to the

processes sequence

of part(s)

A

A

Raw Material

Ready part

B

B

C

D

D F

F F

G


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2.008 -Spring 2004 12

Cellular System

Machines/Resources

are grouped

according to the

processes required

for part families

Raw Material

Ready part

B

B

C

E

E

A

D

D

D

F

F

G


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2.008 -Spring 2004 13

Production Quantity and Plant Layout

Project Shop

Job Shop

Cellular System

Flow Line

1 10 100 1,000 10,000 100,000

Quantity


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2.008 -Spring 2004 14

Production Rates

Case I:

One machine

Everything works

M

timeOperation1rateProduction !


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2.008 -Spring 2004 16

Production Rates (contd)

Case III:

Many machines

No machine breaks down

No buffers

M1 M2 Mi Mk


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2.008 -Spring 2004 17


Case IV:

Many machines (same operation time)

No machine breaks down

No buffers

M1 M2 Mi Mk


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2.008 -Spring 2004 18


Case V:

Many machines (same operation time)

Machine breaks down

No buffers

M1 M2 Mi Mk


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2.008 -Spring 2004 19


Case VI:

Many machines and buffers in between

Machine breaks down

M1 M2 Mi MkB1 B2 Bk-1Mk-1


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2.008 -Spring 2004 20


Production rate increases if:

Increase the rate of the slowest machine

Reduce the disruptions

Introduce buffers

Introduce in-process control


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2.008 -Spring 2004 21

Disruptions

(Random Events)

Machine failure

Set-up change

Operator absence

Starvation/Blockage


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2.008 -Spring 2004 22

Waiting

Underutilization

Idleness

Inventory


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2.008 -Spring 2004 23

Inventory/Work-in-Process (WIP)

It costs money

It gets damaged

It becomes obsolete

It shrinks

It increases lead time


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2.008 -Spring 2004 24

Cycle Time and Lead Time

Order

Supply

Order

Supply

PlantSupplier Customer

demanda erageailytimea aila leailytimeTakt !


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2.008 -Spring 2004 25

Cycle Time

Cycle Time

The time a part spends in the system

Littles Law: L = w

L: average inventory

: average production rate

w: average cycle time


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2.008 -Spring 2004 26

Cycle Time (contd)

Example:

Operation time = 1, One-piece operation

Production rate = 1

Cycle time = 5

Inventory = 5

M1 M2 M3 M5M4


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2.008 -Spring 2004 27

Cycle Time

Batch Production

1.

Operation time: 3 minutes

Batch (Lot) size: 1000Cycle time = 1,000*3 + 1,000*3 + 1,000*3 = 9,000min

Op1 Op2 Op3


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2.008 -Spring 2004 28

Cycle Time

One-Piece Production

2.

Operation time = 3 minutesCycle time = 1,000*3 + 2*3 = 3,006 minutes

Op1 Op2 Op3


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2.008 -Spring 2004 29

Cycle Time and Lead Time

Order

Supply

Order

Supply

PlantSupplier Customer

demandaverageDaily

timeavailableDailytimeTakt !


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2.008 -Spring 2004 30

Systems Design and Operation

Cycle time < Lead time

Lumpiness

Information contents


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2.008 -Spring 2004 32

Typical Design Guidelines

Leveling

Balancing

Single-piece flow

Low materials handling

Low setup time

Smaller lot size

Low WIP

Faster feedback


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plant lay types

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