Cutting ABS troubles

I have used Carvey to ‘mill’ panel cutouts in ABS plastic enclosure with a 1/16" upcut bit for quite some time and it worked nicely and cut clean openings using a whole bunch of shallow cuts. Some months back, maybe about the time Easel came out with the PRO version (which I do not have), the milling parameters for ABS changed dramatically. It seems to cut in one pass now. The plastic heats up and bonds to the upcut bit (see image). The openings are distorted as can be seen in the attached image. Presumably, I need to change the cutting settings. But… why the change and what should I change the settings to?

Go faster and/or lower your RPM, if the plastic melts you are going too slow.
Any feed rate Easel / Easel Pro suggest is only a starting point, each machine is a little different.

Thanks for your comment. I understand that the plastic heats up and bonds. My question was… ‘what changed and why?’ This used to work fine with default settings and now they are dramatically different… multiple shallow cuts vs one pass. If I knew what the earlier settings were, I could just reuse them. But the default settings were changed for ABS plastic with 1/16" upcut bit.

Along with @HaldorLonningdal said, consider a single flute endmill. Also, is the bit new?

As far as the Easel settings…I think I noticed some changes a while ago as well. Any chance your old, successful project saved the settings?

I understand that. I however have never used the Easel defaults hence unaware / ignorant of any recent changes :wink:

Good suggestion. An earlier project showed different settings… 0.03" depth per cut, compared to 0.15" depth per cut in the current project. And checking further I can see that the default for a new project with ABS and the same upcut 1/16" bit is in fact 0.03" depth per cut… so apparently I changed my project settings. A mystery. Thanks for the feedback.

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