In the previous topic I discussed the goal of have a small amount of material at the workstations or Points of Use. How small is small? Toyota Material Handling has a goal of a few hours of usage, and Toyota Georgetown has virtually eliminated line-side material by kitting just about everything (as far as I saw on a recent tour). The primary motivation for this is not inventory reduction, but on space reduction and improvements in operator productivity.
I remember the days when our rule of thumb for Point of Use material was to try to stock at least a day’s worth of usage for as many items as possible. In the DFT workshop that I must have taught 100 times in the 1990’s, the guidelines for inventory quantities were as follows:
We are reviewing the biggest changes in Material Management that have taken place since the 1990’s, and the attitude that Material Management or material handling is a form of “muda” was a big one back then.
Pulling from overseas is of special importance, because without optimizing material flow from outside suppliers and especially from overseas suppliers, it will be very difficult to achieve high overall inventory turns and reduce working capital. (Note: I’m using the term “overseas” to refer to imports from outside of your country. Yes, I know that they may not literally come from across the ocean!) Reducing the amount of material at a workstation is important to save valuation production floor space, improve operator productivity, and reduce part selection errors, but the Point of Use inventory locations represent the smallest part of your total inventory.
There are many “schools” of Lean Manufacturing. Some are closely aligned with the Toyota Production System (TPS), and tend to use a lot of Japanese terms and concepts. Others have Americanized the TPS, and made it more culturally accessible in the United States and other countries. The approach to Kanban will vary depending on which school of thought you were trained in.
Welcome to Part 5 of a 5-part series on Lean Design. If you are still here after reading Parts 1-4, you are probably convinced of the importance of achieving “flow” in your business and manufacturing Value Streams! In this lesson I’ll summarize the four main paths available to you to build your skills in Mixed Model Line Design and Mixed Model Material Management, which I consider to be core knowledge for any Lean Specialist, Manufacturing/Industrial Engineer, or Material Specialist.