I am having some surface finish issues with pockets that I am milling out of HDPE on my Shapeoko XL Dewalt. At the bottom of the pockets are these patches of fluff, that I can easily scrape off, but they’re just a pain. I want to fix it so I don’t have to do so much post-processing.
I’ve had the issues with my 1/8in and 1/4 endmill. Here are my settings for the 1/4 in:
2 flutes
Feed rate: 80 in/min, but I tried slowing down to about 60.
DOC: .125 in
RPM: 4 ( I think about 21,5000)
I created the gcode in the free version of Carbie Create. Happy to give any other info.
what are you setting as stepover?
If you’re using carbide create… for the bottom layer it’s best to set it a bit smaller… 40% or less of the diameter of the tool.
Have you tried feeding faster ? HDPE is like butter, and with a 2-flute you should be able to double that 80ipm feed. Try it with the 1/4" endmill first, and possibly reducing DOC initially to be on the safe side, but this should tell you if the bottom of those pockets gets cleaner.
You can get tools with a small corner radius designed for floor finishing plastics. Reduces likelihood of the small burr that tends to develop and/or the faint circular tool mark left by the leading edge. I rarely need/use them. But put them into service on aesthetic pockets from time to time.
@Jopeep I will need to verify this evening once I get home, but for a 1/4" 2 Flute I typically run 16K RPM, 160 IPM (reduced on lead ins & lead outs) with a 1/8" stepover & 1/8" stepdown when I rough out my HDPE molds.
