Lean Manufacturing

Julita (222010006)Teknik Industri - Ukrida

Batch Reduction

Batch Reduction

Definition and PhilosophyThe batch size is the unit at which work-products move between stages in a development process.

Historically, manufacturing companies have operated with large batch sizes in order to maximize machine utilization, assuming that changeover times were “fixed” and could not be reduced

Mr. Taiichi Ohno: “Because Lean calls for the production of parts to

customer demand, the ideal batch size is ONE or make one and

move one.”

When can we reduce lot size without reducing throughput?

When the setup time is small (setup reduction)

When there are no constraint in inside the manufacturing process

Set the lot size as small as possible while not allowing a non-bottleneck to become a

bottleneck

One way to reduce production lead time and WIP for a process

batch of any size is use lot splitting and move the lot to subsequent operations in

smaller transfer batches.

Transfer Batches

However, a batch size of one is not always practical

So the goal is to practice continuous improvement to reduce the batch size as low as possible.

Optimum batxh size are calculated starting

with:The most critical work

centresThe largest inventory

carrying costsThe higher risk

processesThe most

unpredictable process

The LeannessIf a batch is larger than the next process needs to start work and continue steadily

If defects are discovered in a small batch, say ten pieces, then the economic loss may be minimized

The waste of waiting will occur as a result of overproduction

Large batch sizes have a negative

impact on all three phases of

production - raw materials, work in

progress and finished goods

Large amounts of

inventory at any stage will

lead to transport and

storage problems

OVER PRODUCTION

DEFECTS

WAITINGINVENTORY

TRANSPORT

The Benefits of Batch Reduction

0 1000

Operation

D

B

C

B

A

Hours

200

400

600

800

1000Inventory

0 1000 2000

Operation

D

B

C

B

A

Hours

200

400

600

800

1000Inventory

Reduces cycle time and gets

quicker feedback

Reduce risk of an error or

outage

Smaller finished goods

inventory

Smaller manufacturing

investment

Safety work environment

Major factor in smaller transfer batches is materials handling.

distance over which materials are moved.number of steps or transactions involved in the

move.complexity or sophistication of the material

handling system

Reducing distance:locating equipment close together (cells, no

backtracking)reducing need for conveyance systems, forklifts, etc.

The Major Factors of Batch Reduction that must be considered

Jaguar, one of the world’s most prestigious car manufacturers, has employed lean manufacturing processes. Jaguar is part of the Ford Group.

One of the most significant changes has been creating continuous flow system of production based on a ‘just-in-time’ approach.

The success keys are: Removing over-production. Producing

too much, too soon takes up storage space, and involves extra handling. Parts and products which have to wait to be used can be damaged, or become obsolescent, leading to wasteful scrap.

Cutting inventory - i.e. the build up of stock. Only the minimum amount is required to get the job done. Having too large inventories causes interest charges and storage costs, uses up space and creates extra handling.

Success Story

One of the primary objectives in Lean Manufacturing is the reduction of batch sizes approaching one-piece flow.

Reducing batch sizes reduces the amount of work-in-process inventory (WIP), production lead-time.

Smaller batch size enabling companies to deliver more quickly and to invoice sooner (for improved cash flow)

It is important to improve setup time so that can successfully reduce batch size.

Conclusion

Nicholas, John M.. 1998. Competitive Manufacturing Management. New York: Mc GrawHill.

Liker, Jeffrey K.. 2005. The Toyota Way. Jakarta: Erlangga. Wilson, Lonnie. 2010. How to Implement Lean Manufacturing. New York:

Mc GrawHill. http://businesscasestudies.co.uk/jaguar/lean-production/ownership-of-

work.html#axzz2aeE9IQOP http://businesscasestudies.co.uk/jaguar/creating-world-class-performance-

in-a-jaguar-assembly-plant/conclusion.html#axzz2aeE9IQOP http://www.kellogg.northwestern.edu/course/opns430/emp/vanmieghem/

slides/VanMieghem_EMP-3LeanOps.pptx http://www.iienet2.org/uploadedfiles/SHS_Community/Beginning%20the

%20Lean%20Improvement%20Journey%20in%20the%20Clinical%20Laboratory.pdf

http://staf.uum.edu.my/rizal/words/bjmp5023/12leanthinking.ppt web.utk.edu/~kkirby/IE527/Ch5.pdf http://www.leanpractitioners.co.uk/Reports%20&%20Articles/SW

%20Batch%20Size%20Reduction.pdf http://www.docstoc.com/docs/51919237/6A-Batch-Processing-versus-

Single-Piece-Flow http://chohmann.free.fr/production/rsto2_us.htm

References

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