machining HDPE to high finish

May 02, 2006 3 Replies
L

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


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P

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

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G

"Polymer Man" wrote

Agreed. Acetyls like Delrin are definitely the way to go. Just keep your tools sharp and polished and the surface comes out wonderfully. Surface energy of acetyls is only slightly higher than UHMW so almost nothing will stick to it.

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T

Is delrin food safe? When I was doing plastics for a living 15 years ago, we used Celcon(sp?) for food contact acetal.

Just a thought or two.

Mike

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