Experience Milling HDPE?

Has anybody had success milling HDPE ?

I have tried several flat and ballnose endmills, from 6mm diameter down to 1/8" with marginal success. I’ve used my Router with great success - buttery smooth cuts and finish, but the Nomad gives me a stringy spaghetti mess. If I try to take a slightly deeper depth of cut, or stepever, then the spindle stalls. Seems to be no happiness in the middle. I’ve been mostly using conventional milling, but have also tried climb milling and that seems even worse.

I’ve got a couple other end mills I’ve not had a chance to try on HDPE… a few single flutes designed specifically for plastics which have worked spectacularly on acrylic, and some downcut mills for wood and plastic.

Was just wondering if anyone has had success and could share experiences ?


I had really great success with HDPE with this project. Perfect little chips, super super smooth cuts.

I’m no plastic/materials expert so I don’t really know if there are many kinds of HDPE plastics and how much they differ, but I walked into TAP Plastics and specifically asked for “food safe, >100 degree C melting point, easy to machine” plastic and he pointed me at this stuff called King Starboard HDPE. I don’t know if that differs from what you have.

But if it helps, I was using the .125" endmills that came with the nomad (so, 2 flute).
7500 rpm spindle speed
68.3 in/min cutting feed rate (feed per tooth .0046")
17.075 in/min plunge feedrate
.03" stepdown
All climbmilling

If you’re using the MeshCam Carbide Auto Toolpath thing I think it’s almost identical to the Wood-Hard settings except more aggressive (twice) stepdown, and it’s much more aggressive all around than the Plastic-HDPE settings.

I was more interested in getting this done than experimenting, but I feel like I might have been able to go more aggressive if I wanted.


With HDPE you want to use conventional milling. It does leave a fuzzy, stringy edge when you use climb milling.