Jack,
One of the things I’ve learned from Toyota is to ask why five times. You got to about three. The real why here is the source of the design engineers – ME depts. – real good at heat transfer, fluids, thermo, and real bad at manufacturing processes and manufacturing systems and usually NO course in quality engineering and no lean course that would talk about designing in quality to the process. These guys have big egos and usually have no clue about the manufacturing revolution that has taken place over the last 30 years. A real big part of it is the computer software they use for design and manufacturing — it assumes the manufacturing system is a combo of the flow shop/job shop known as mass production. Finally, there is no point in doing lean product design if you are not doing lean manufacturing system design and lean engineering of the factory.
