Inputs, Process Control and High-Variety Manufacturing

I was reading a chapter in Lean Manufacturing for Job Shops (Tristani and Irani) that introduces the concept of process control. The following statement resonated with me:

" . . . consistent inputs help give better internal work-center-to-work center quality, which tends to lower the amount of re-work a job requires. That means the work content is less, product cost is less, and product lead time through the shop is improved."

I believe that many manufacturers overlook what should be one of the easiest and potentially most critical input to control: their manufacturing documentation.

In high-variety manufacturing (HVM)*, by definition, there is variety and variation of products manufactured, and, in many cases, uniqueness of product. That means that the manufacturing documentation which details the specific requirements of the specific product or product variation to be manufactured is absolutely critical to the effectiveness (productivity and quality) of the manufacturing process.

There is no universal standard for manufacturing documentation; in HVM, especially, it needs to mirror the variation and variety of product. It must, however, include all relevant content and present it in a way that reduces and/or clarifies complexity. (One common error is to include too much irrelevant information that ends up obscuring the most critical information.) The physical organization must match the workflow of the shop floor, as must the specific presentation match the needs of each process step. That is, a drawing may be needed for some steps, but other steps may just need a dimensional cut list. In some cases generic assembly instructions or drawings may not be needed in the packet itself, but accessible on an as needed basis. The documentation also needs to reflect the needs of the workforce in terms of language and technical literacy.

Too many times, however, the manufacturing department just accepts what it receives as either it doesn't realize that the documentation can be improved or it's been told that that is another department's responsibility and not its concern. Both of these conditions, and the lack of control and quality in the manufacturing documentation, are symptomatic of a larger issue: the lack of understanding that in HVM "production" or "operations" encompasses more than just the manufacturing floor and that, as such, process and quality improvements, whether lean or other methodologies, need to extend beyond the factory threshold.

More on this subject forthcoming.

* High-variety manufacturing includes types such as job shop, build-to-order (BTO), configure-to-order (CTO), engineer-to-0rder (ETO), mixed model, high-mix low volume (HMLV), mass customization, modular, and so forth.

"Lean Manufacturing for Job Shops" - a great new book

A great new book and resource has just been published: Lean Manufacturing for Job Shops by Robert J. Tristani and Dr. Shahrukh A. Irani. The information site is www.geocities.com/Robert_Tristani .



The book has a unique format which adds to its usefulness. The story of Southern Foundry and Pattern Works, a fictional job shop implementing the job shop lean principles, is intertwined with the textbook portion of the book. This format really helps the reader grasp the concepts and how to apply them. It also helps the reader visualize how these critical principles can be applied to other job shop and high-variety manufacturing scenarios.



The book is packaged with two additional resources: a CD about Value Network Mapping (VNM) and a CD entitled "How a Jobshop Developed their In-House Training Video on Waste Elimination." Anyone who has tried to do a Value Stream Map of a non-repetitive process knows the limitations thereof. Value Network Mapping solves those problems.

I strongly encourage everyone in high-variety manufacturing to get this book and its companion resources. I foresee using it as not just a resource for the shop floor but for management, as well.