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427- Lean Production Systems Dr. Rupy Sawhney

partment of Industrial & Information Engineeringe University of Tennessee 1

Dr. Rupy Sawhney

Current Process

Bad Leadtime

Better Leadtime

Proposed Process

Time partenters the

system

Time partexits thesystem

Time partexits thesystem

LEAN G OAL 1: R EDUCE LEAD TIME

What Is Lead Time?

Receive Computer Input

Schedule

DataSet

Materials Manager

ProcessSet - UpQueueMove

Value AddedNon Value Added

Shop Lead Time

Shop Lead t ime is the time that it takes a part to becompleted within manufacturing

Reduction of ConveyanceTime between Production.

Adaptable Production or JIT

Reduction of the Production Lead Time

Reduction of ProcessingTime at each area.

Reduction of WaitingTime between Processes.

Quick ConveyanceMeans.

LineBalancing.

Minimization of Conveyance lot.

Belt, forklift,Conveyor.

Standardizationof jobs.

Mutual relief movement.

Reduction oflot sizes.

Leveling of workLoad by sequenceSchedule.Layout of

Machines.Multi functional

Workers.

Quick ConveyanceMeans.

Single UnitProduction

& Conveyance.

SmallLot

Production.

SMED

Lead Time Analysis

ProcessSet- UpQueueMove

How to Think Where the ProblemIs?

4%2% 3%91%People WorkPeople Work People WorkNo One Works

Here

Variation is Evil

LEAN G OAL 2: R EDUCE VARIATION

Total Variation

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427- Lean Production Systems Dr. Rupy Sawhney

partment of Industrial & Information Engineeringe University of Tennessee 2

LEAN G OAL 3: C HANGE WILL ONLYCOME THROUGH P EOPLE

To eliminate muda (waste or non value

added) in the process, in order to let thebusiness grow in a more efficient manner. Result: More profit using

the same or lessresources.

What is waste?Value is what the customer buys. It is a function of quality, time to deliver and price.Value addition Transforms or shapes material or information Done right the first time Customer wants it

Non-Value but Necessary Waste Consumes resources Cannot be eliminated based on current technology or policy Project coordination, company mandate, regulatory, etc.

Non-Value and Pure Waste Consumes resources Rework , Check offs, etc. Can be eliminated

Deborah Nightingale, 2005 Massachusetts Institute of Technology

Overproduction Inventories Transportation

Defective products Processing Motion

Delays

An eight source hasbeen considered bysome authors:Waste of humantalent.

Dr. Stainbacksuggests Waste inCommunications

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427- Lean Production Systems Dr. Rupy Sawhney

partment of Industrial & Information Engineeringe University of Tennessee 3

Overproduction:

The waste of overproduction is producing too much at a given time. It ischaracterized by,

Producing more than is needed by thenext processor customer Producing earlier than is needed by the next processor customer Producing faster than is neededby thenext process or customer

Inventory:

Inven to ry i s considered a was te as it does not add any value to theproduct. Parts, raw materials, WIP, inventory, supplies and finished goods are allforms of inventory.

Repair / Rejects:

Whenever defects occur, extra costs are incurred reworking the part,rescheduling product ion, etc . This resul ts in labor costs , more t ime in the"Work-in-progress". Defects in practice cansometimes double the cost of ones ingl e p roduct . Thi s canno t be pas sed on to the consumer and should betaken as a loss.

Caused by:

incapable process;

incapable suppliers;

operator errors.

Motion:

Any motion of man and/or equipment that does not add value to theproductor serviceis considered a waste.

Caused by:

Poor workstation layout excessive walking, bending reaching;

Poormethod design transferring parts from one hand to another;

Reorientation of materials.

Processing:

Over-processing occurs any time more work is done on a piece than isrequired by the customer. This also includes using components that are moreprecise, complex, higher quality or expensive than absolutely required.

Painting of unseen areas.

Unnecessarily tight tolerances.

Cleaning and polishing beyond the level required.

De-burring areas never accessedby the consumer.

Waiting:

Any kind of a wait either due to operator, machine downtime, etc areconsidered wastes.

Waiting for thenext production stepInterruptions of production during shift change.

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427- Lean Production Systems Dr. Rupy Sawhney

partment of Industrial & Information Engineeringe University of Tennessee 4

Transportation :

Transportation does not make any transformation to the product that

theconsumer iswilling to pay for.

Caused by:Poor layouts;Multiple storage locations;Lengthy, or complex material handling systems.

What happened here?

Scrap CapacityImbalances

Large Setup Unrel iableTimes Suppliers

Toyota Production System (1998), Yasuhiro Monden

Toyota Production System (1998), Yasuhiro Monden

Over ProductionInventoryTransportationWaitingOver ProcessingDefectsMotion