Feeds and Speeds for HPDE

I have GWizard Calculator and I have cut HPDE before. I recently got the two tone HPDE from Inventables and today when I get to mill it I am getting no chips. Only this:

Any idea what I need to change?. I think it will be cleanable but HPDE has cut smooth as silk before. Maybe this is not HPDE?.

My Settings:

Might try lower RPM - you may be getting melting that’s sticking the chips back to the material.

Increase stepover?

A further note: “With HDPE you want to use conventional milling. It does leave a fuzzy, stringy edge when you use climb milling.”

That’s EXACTLY what it looked like when I milled something in Ultra High Molecular Weight… It looked like a cat was lying on it.

@patofoto What end mill are you using? Looks like an upcut with a few flutes? I get super clean cuts with spiral “o” single flute. You can find the .125" ones really cheap. A straight flute bit would do better than what you’re getting there.


Thanks, everybody!. I suspected my endmill because I used my 1/4" 3 flute endmill and it cleaned up everything perfectly. I was using the 1/8" 2 flute endmill from Carbide 3D. Is it an upcut?. Will test others. @neilferreri What is a spiral “o”?. I was starting to get too confident and took the GWizard numbers as gospel and just went ahead and started a job. Lesson learned. When using a new material you haven’t used before, test, test, test!!!

@patofoto This is what I was referring to.
I’ve used cheap ones like these with success.