Machining Delrin to high Flatness and Parallelism
Machining Delrin to high Flatness and Parallelism
(OP)
Hello All
I need to machine a plastic piece that is rather thin with high flatness, parallelism and surface finish callouts. I was thinking of lightly thinning some stock high-maintainability Delrin. See the drawing below:
http://imgur.com/igV3fsB
The piece is 190mm X 100mm. Now these tolerances may be unreasonable, but what could be realistically be hit by a CNC milling machine without getting too expensive or complex? Is there a plastic material more suitable to this application than Delrin?
Thanks!
Justin
I need to machine a plastic piece that is rather thin with high flatness, parallelism and surface finish callouts. I was thinking of lightly thinning some stock high-maintainability Delrin. See the drawing below:
http://imgur.com/igV3fsB
The piece is 190mm X 100mm. Now these tolerances may be unreasonable, but what could be realistically be hit by a CNC milling machine without getting too expensive or complex? Is there a plastic material more suitable to this application than Delrin?
Thanks!
Justin






RE: Machining Delrin to high Flatness and Parallelism
Ordinary Delrin can be machined as flat as you specify.
Don't expect to measure it half an hour later and get the same numbers.
If you assemble the part between two other parts, and e.g. rely on the flatness for sealing, do the assembly immediately after finishing.
Remember that Delrin is a condensation polymer, and has a thin layer of 'foam' in the middle of its cast form. You probably need to try shaving both sides of 1/4" cast material, or bandsawing the outer faces off 1" cast material.
I don't know which will warp more.
Mike Halloran
Pembroke Pines, FL, USA
RE: Machining Delrin to high Flatness and Parallelism
I believe 3/8" sheet stock will be purchased and then about 2.86mm will have to be removed total, from either side.
RE: Machining Delrin to high Flatness and Parallelism
Dr. Chris DeArmitt
Plastics consultant to the Fortune 500: www.phantomplastics.com
Webinars on plastics, fillers & impact modification: www.plastictraining.com
RE: Machining Delrin to high Flatness and Parallelism