Lean manufacturing is nothing new. Many say it was invented shortly after World War II, when Japanese industrial engineer Taiichi Ohno, together with coworker Shigeo Shingo, developed the Toyota Production System (TPS). Others say Taiichi simply took Henry Ford’s assembly-line way of thinking to the next logical step.
Whatever the case, people have been attempting to increase the efficiency of their manufacturing processes since the days of Eli Whitney, and if you’re to become a valued machine-shop citizen, you should attempt to do the same thing. It begins with eliminating waste, which in Lean terminology is called “Muda.” These include:
- Transport (moving stuff around needlessly creates the risk of it being damaged or lost)
- Inventory (too much material, too little material, or material that is too late all cost a company money)
- Motion (unnecessary movement of people and machines, like walking too far for tools, and inefficient computer numerical control [CNC] programs)
- Waiting (also known as work in process, or WIP, which in a machine shop means partially completed parts waiting for the next operation)
- Overproduction (making too many parts or parts that are too early for the customer’s needs)
- Over Processing (machining to greater accuracy than required on the drawing is one example)
- Defects (this one’s a no-brainer; scrap or defective parts are bad for everyone involved)
If you’re looking for an easy way to memorize all of that, just look at the first letter of each word. They spell TIMWOOD. Of course, other Muda have been identified since the early days of TPS, most notably Skills (that is, not utilizing the skills each of us brings to work each day), thus extending the acronym to TIMWOODS. Either way, it’s a handy way to remember the “deadly sins” of waste.
The fathers of Lean have all gone to the great factory floor in the sky, but many others have taken the Lean baton and run with it, and today Lean is an all-encompassing system of shop-floor improvement. It includes JIT (just-in-time) delivery of products, SMED (single-minute exchange of die), Kanban (pull-type scheduling), Six Sigma (defect reduction leading to process improvement), DFM (design for manufacture, which I discuss in Chapter 9), and much more.
Want to get started with Lean but don’t know where to go? The first step is to pick up a book on the subject. Google “lean manufacturing” and you’ll find consultants galore, although hiring one isn’t a prerequisite to implementing Lean (even though some of them will tell you it is). Lean seminars, advice from customers and other shops, and even the Internet have loads of information on Lean — what are you waiting for? Get Lean.