Lean Quote: Reducing the Batch Is Advantageous

In Lean Quote
September 23, 2016
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On Fridays I will post a Lean related Quote. Throughout our lifetimes many people touch our lives and leave us with words of wisdom. These can both be a source of new learning and also a point to pause and reflect upon lessons we have learned. Within Lean active learning is an important aspect on this journey because without learning we can not improve.

“If we reduce batch sizes by half, we also reduce by half the time it will take to process a batch. That means we reduce queue and wait by half as well. Reduce those by half, and we reduce by about half the total time parts spend in the plant. Reduce the time parts spend in the plant and our total lead time condenses. And with faster turn-around on orders, customers get their orders faster.” — Eliyahu M. Goldratt, The Goal

In the book Lean Thinking, James Womack and Daniel Jones recount a story of stuffing newsletters into envelopes with the assistance of one of the author’s two young children. Every envelope had to be addressed, stamped, filled with a letter, and sealed. The daughters, age six and nine, knew how they should go about completing the project: “Daddy, first you should fold all of the newsletters. Then you should attach the seal. Then you should put on the stamps.” Their father wanted to do it the counter-intuitive way: complete each envelope one at a time. They told him “that wouldn’t be efficient!” So he and his daughters each took half the envelopes and competed to see who would finish first.

The father won the race, and not just because he is an adult.

Check out Gemba Academy’s “one piece flow” square off against “mass production” video.

When we work with small batch sizes, each batch makes it through the full life cycle quicker than a larger batch does. We get better at doing things we do very often, so when we reduce batch size, we make each step in the process significantly more efficient.

There are very good reasons why batch size is important. Some of these benefits are:

1) Improves Quality (reduces defects). Making 1 piece at a time prevents a pile of scrap when issues are caught on a single piece versus a batch.
2) Reduces Inventory. WIP (work in process) inventory is reduced when manufacturing one piece at a time.
3) Improves Safety. Less inventory means less clutter and safer work environments. It takes less effort to move 1 piece than big batches.
4) Increases flexibility. Less inventory, rework, and scrap make short cycle times possible providing more opportunity to react to customer demands.
5) Requires less space. With less inventory more space is available for value added activities.
6) Increases productivity. Most of the 7 wastes found in typical batch and queue processes are eliminated or reduced with single piece flow.

Reducing the batch size in manufacturing is therefore a desirable goal: it improves the speed of response to the customer, whilst improving the ratio of value-added to non value-added work. A silent productivity killer, batching is an extremely difficult mindset to overcome and, as a result, numerous Lean initiatives have been destroyed by it.