[omnifrog]

I'm currently designing an insulating layer between two metal tubes. This plastic piece is a tube with one end closed and the other open (think test tube and you are close, squared off like a graduated cylinder and you are even closer). Keeping the diameter small is critically important, so we're trying to make the sidewalls as thin as possible. The spec calls for at least .4mm of material. The tube is roughly 27mm in diameter and about 100mm long. Most commonly used plastics are appropriate, although polycarbonate has worked well in this application in the past.

My question: Is a .4mm sidewall fairly easily achievable by most machine shops with +.05mm on the inside and -.05mm on the outside as tolerance? In my initial design I upped it to .75mm, but my customer really wants me to shrink the size by a mm and I'm looking everywhere, including the tolerancing budget.

Thanks

[mmoe]

I've cut down to a .75mm sidewall in ABS while holding a +/-.05mm tolerance (or even a bit better), but I think that's about as thin as you'll be able to reliably cut a plastic.

[omnifrog]

That's a bit disheartening. But thanks for the quick reply!