A Simple Tolerance Change That Can Significantly Reduce Manufacturing Cost

It reminds me, long, long ago, I was working as a student intern in a drafting shop. I labeled a quarter-inch hole 0.25000". One of the engineers there pointed out to me that this implied precision to the machinist in the shop, and if he took it literally, it would be expensive to make the part.

Live and learn...

We repeatedly determined our process capability and designed mating parts so that tolerances would be achievable and so that fit was always possible.

We developed a means to fit our parts into rectangular receiving holes in material of varied thickness and hole tolerance by simply putting a taper on the compressed clip rather than try to get exact thickness fit. No rattle, ever. Auto industry worldwide was using this when GFC happened and we closed.

DFMA principles to reduce component count by combining items that could be common material (injection moulding).

Interchangeable tools in shop all same "thickness" so that machine clamping never had to be adjusted. Saved time on EVERY tool changeover. We ran 25 machines with typically 10 changes per day.

"Crush ribs" on mating parts so that only small material volumes were needed to be deformed to achieve fit.

Corner radius ALARP to eliminate/reduce stress focus on inside corners of parts. Easier to machine.

Lots of other things associated to JIT, SMED, KANBAN etc.

Gee I miss those times.