Lloyd E. Sponenburgh wrote:
Anyone here have experience machining HDPE?

I need some tips on how to get a (very) nice finish. The piece is a mould
for a complex profile to be made in a sugar paste, and if the surface isn't
nearly a high polish, it sticks too badly to remove the moulded item.

Rakes? Speeds? Secondary finishing methods?

There are several different tapers on the tip, and they must be maintained
to a few thou accuracy, so heat polishing isn't an option unless it can be
done in a manner that doesn't distort the shape.

Thanks,

LLoyd




HDPE isn't the best material for a mold for those reasons. Try Delrin.
It cuts to a fine finish and can be buffed.