No such thing as a “Lean Job Shop”

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As I visit companies in Ohio, Indiana and Michigan, I consistently hear that lean manufacturing does not work in job shops. The belief is that lean manufacturing only works in low mix/high volume environments, e.g. Toyota, but not in the high mix/low volume environments typified by most job shops. In other words, there is no such thing as a lean job shop. After all, if Toyota is the world-class example of lean, that should be proof enough!

This belief is completely understandable but operationally incorrect. Lean manufacturing is equally applicable in small job shops just as it is in large repetitive operations.

To understand why this is so, it is important to remember the purpose of lean manufacturing, i.e. reducing or eliminating process steps that do not add value in the eyes of the customer. Therefore, it does not matter what the size or type of shop is it only matters what steps are being performed that the customer does not value.

Years ago, I heard a definition of value from the customer’s perspective that has stuck with me. Value is those process steps that physically change the product and that the customers are willing to pay for. When a part is being machined, the part is changed physically and the customer is willing to pay for that. However, when the feedstock is being loaded into the machine, the part is not changing and the customer doesn’t want to pay for that operation. It is understood that not all processes that do not add value ‘in the eyes of the customer’ can be eliminated of course, but it does not negate the need to reduce or eliminate as many of them as possible.   

The application of lean in a job shop is different than the application in the low mix/high volume operation. Figure I shows 20 tools which can be used in a lean implementation. It is not required that all of them be used, instead think of these as the tool box from which you use the most appropriate tool. But notice, regardless of the tool(s) chosen, they all lead to continuous improvement focused on the customer.

Figure 1 (copyright TE 2010)

5S is an example of a lean tool that applies in any size shop. The 5S’s are Sort, Set, Shine, Standardize and Sustain. 5S is all about getting organized and staying organized.

SMED (Single Minute Exchange of Dies) is another tool that most organizations can use regardless of size.  SMED is all about reducing change over time. The shorter runs that are the nature of job shops clearly would benefit from finding ways to reduce setup times between jobs.

Recognizing that job shops can benefit as much from lean as any other enterprise, Dr. Shahrukh Irani, President of Lean + Flexible LLC, makes the following observation:

The Principles of Lean as described by the Lean Learning Institute are universally applicable in any manufacturing sector. To this day, job shops often implement lean taking a cookie-cutter approach based on the Toyota Production System (TPS). While some gains are realized, a better approach is JobShopLean. JobshopLean implements the Principles of Lean as follows: (1) Identify the product families, (2) Design a Hybrid Cellular Layout for the facility that fits the overall material flow implicit to their product mix and (3) Schedule daily operations using Finite Capacity Scheduling software (instead of relying on their ERP system).”

If you would like to learn more about taking advantage of lean manufacturing in your business, please contact the Great Lakes Trade Adjustment Assistance Center, www.gltaac.org.

The Great Lakes Trade Adjustment Assistance Center (GLTAAC) is a federally funded, non-profit organization that provides business assistance to manufacturers that have been directly hurt by imports. We bring the TAAF program to firms in Ohio, Indiana and Michigan.