Alain Prioul

JUNE 2010

FIXED BATCH KANBAN SYSTEMAND LEAD TIME CONTROL

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FIXED BATCH KANBAN SYSTEM

AND

LEAD TIME CONTROL

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PULL SYSTEM - MIFA

TPACustomer

Process 1

Process 2

PC & L

NO LEAD TIME CONTROL

Process

Stagnation

Purc

hase

d pa

rts

Leveling board

Production Lead Time

F. G.Shopstock

Batch building

Demand : forecast/firm

A B C

ABC

NO CONTROL OF THE FLOW

ABC

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BATCH PRODUCTION

A B C A

Stock A =

Lead time of A

time

TPACustomer

PC & L

Leveling board

Demand : forecast/firm

Batch building

A B C

ABCProcess

1Process

2

Purc

hase

d pa

rts

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FIXED BATCH CONCEPT

A B C A

Fixed ?

Fixed duration Fixed quantity ?

Production Cycle Time of A or B or C

Packaging of A or B or C

Nb of Kb in one lot vary with

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FIXED QUANTITY BATCH : LEAD TIME VARIATION

If production duration of B or C is longer, Lead Time of A is longer. Same for B and C.

Same consequence if tool change time is longer than standard.

A B C ACB A

Lead Time A

Stock A

Stock Shortage A

Batch is longer than standard

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Unleveled Withdrawals

Schedule change

POOR LEVELING ALSO IMPACTS LEAD TIME

A B C A BB A

Lead Time A

PIK

A B C

Shopstock

WK

C

AB

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CAUSES OF LEAD TIME VARIATION

Production time longer than standard

Tool change longer than standard

Unleveled withdrawals

Stagnation of information

Even when we fix the quantity of Kanban in a batch, we do not control the Lead Time

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PRODUCTION PATTERN

A B C A B

Schedule is pre-define

Changeovers are planned

B C A

8h 10h 12h 14h 16h

8h 10h 12h 14h 16h

LEAD TIME IS UNDER CONTROL

A

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PRODUCTION PATTERN

Demand stability

Line reliability

OPR control

Pre-requisites

PIK

A

B

C

A B C A BProduction pattern

A BC

Daily demand

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Production pattern

Good visualization of future changeover

Synchronization with preceding or next process is possible

Strong incentive for beeing lean

Advantages

Becomes difficult when law runners are not predictable

No adaptation to demand variations

Disadvantages

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TO REMEMBER

Fixed batch Kanban system do not ensure systematically stability of Lead Time

Lead Time Control is key to control plant performance

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