Feeds and speeds for epoxy

I don’t have much experience with epoxy and it shows. I wanted to do a multicolored inlay in epoxy so I carved the pocket for the first color .11inches deep. I let it set for 3 days and when I went to carve it, it melted and stuck to the bit. I have tried 10000 rpm to 22000 rpm, and have slowed the travel of the cnc way down too. It still melted.

Any thoughts or ideas on this one?

Thanks for any help.

I don’t have any experience with epoxy but I’m thinking if it’s melting you probably want to increase the feed reed rate and or lower the rpm but not lower them both.

I don’t know if you have a O flute end mill for plastic but when I got one it stopped all my melting problems with acrylic etc. I don’t know if they are recommended for epoxy but maybe it’s something you can research. You can see in the photo how the end is different with the O flute end mill. Just a guess on my part but I’m thinking the angled end decreases the contact area leading to less friction and heat.

Not sure if your doing another inlay in the epoxy but if so maybe just doing the roughing with a O flute would get rid of enough material to let the v-bit work without melting. Also if the second inlay is only in epoxy maybe you don’t need the v-bit, I guess it depends on how sharp any corners are as to whether you can do a conventional inlay.

Like I said, no exp, just ideas. Good luck!

Thank Michael, for what I want to do I need a 30 or 60 degree v bit. There has to be a way to do it, I see it all the time on Youtube but they don’t really get into details about bits, feeds, and speeds

When I have milled epoxy, I just used the same feeds / speeds as the wood that I was carving along with it (since it was an inlay that I then skimmed excess off of - too much excess, but that’s a different story). I seemed to have no issues at all. I was just using the recommended general wood speeds that Sienci has in their charts. Hope that helps!

I ran into the same issue trying to do some multi-rout tests. Turned out my epoxy pour had some issues and while it seemed solid on top, it was still a little gummy in the middle, probably because my cellar wasn’t very warm.

I set up a plastic tent and put a metal table with an electric radiant heater under it, which got to about 80F. When I did my next attempt, I made sure to thoroughly mix for 5 minutes before pouring. I let it sit on the table for 4 days just to be sure and didn’t have any issues with a v-bit when I did my cuts.

I let it sit for several days and it was only .14 inches deep. I used the same speed and feed as the wood with the first try and I tried several different speeds and feeds after I saw the melt and still no luck. The bit was a single flute 30 degree bit and the epoxy melted and stuck to the bit at all the speeds and feeds I tried.

I can try letting it set longer and see what happens.

Thanks for the input everyone.

I can try letting it set longer and see what happens.

Thanks for the input everyone.

24 hours has always been enough for epoxy for me. I basically use the same settings as plywood/softwood. Epoxy looks and feels hard, but I found it’s not really all that hard for a CNC bit. If it’s melting, then you are either not traveling fast enough, or RPM is too high (or combination of both), IMO. I do find that it gets kind of stringy and sticks to my dust boot brush and vacuum hose a bit though.

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