Milling plastic 1st and 2nd attempts

My first attempt at milling polyethylene, actually- might be acetal idk:

Second attempt:

3mm DOC speed 4 on makita and 12mm/s

Mmmm, chunky chips

And this is its application - motor mount


I have been cutting a ton of that this week, I have similar settings to you. The part I can not figure out is finishing pass. I am finding slightly lighter roughing passes and no finishing pass leaves the best edges…but I still get noticeable cut marks. I am very happy with the finish but I assumed I could get it perfect since it is so easy to cut otherwise.

But when I chamfer the edges I am running a two flute even slower than the single flute and getting a flawless edge. Maybe it is the straight flute/vs upcut??

Second attempt is using a 1 flute spiral intended for aluminium. The first attempt was with your 1/8 down cut that I use for everything but that doesn’t clear the chips obviously.

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Sorotec has a special endmill just for that, maybe you can find one in the US as well.

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Yeah the surface finish on this isn’t good but in this application I don’t give a hoot :slight_smile:

If this doesn’t work aluminium plates are the next step!

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I’ve milled PA and PE. Sharp tools (new) and cutting edges should not be too dense so that the chips fly out. Low rpm and fast feed. In my opinion, in these materials the chips are allowed to be large.

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