Lexan CNC Feeds and Speeds Inquiry

Hey, our team looking at getting our lexan CNC’ed. With the way my VCarve file is set up, I’m looking at using a 1/16" end mill to get my parts done. However, I was using some online feeds and speeds data to get it done, and I’ve been having issues with warping and melting the lexan. Specifically, my specs are:
Tool: 1/16" flat end mill
Feed rate: 14.173 in/min (360 mm/min)
Plunge rate: 1.81 in/min (46 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.010" (0.25 mm)
I did try it twice, once with the above numbers and another run with a higher feed rate, as the initial run was just too slow. I didn’t really see another option out there, both on this Forum or otherwise, as to better numbers I should be using. Does anyone have established feeds and speeds they are willing to share for this bit size? Thanks for all the help!

For the lexan melting and warping, is the bit an upcut or down cut bit and how many flutes does it have?

Not exactly sure, but there is the set of bits I ordered.

So you ordered or are you using them currently? If you are using the ones you ordered they’re upcut bits which means the problem isn’t the bit being down cut, however it might be a dull bit or its taking out too big of chips while cutting which means you need to keep the spindle speed but lower the feed rate and possibly the plunge rate.

Brand new bits, this is what I used for both tries. The first feed rate was ridiculously slow, could the issue be too many passes? Same website recommended 0.01 per pass, I tried that and up to 0.02, but that would still result in 3+ passes.

Okay, the link is being weird, but the exact bit we got was the third option, which is specified as " 1/16" x 1/4" "

So if it’s lexan I’d imagine it would be a low material thickness in which I would do one initial pass so there is one really thin layer left and then a final path to cut it out, and I (not for lexan but for most materials I cut) would use a feed rate of 5-7 which seemed to be fast enough and keep the cuts clean.

5-7 inches per minute or second? If you meant second, should I be concerned with the increased side load or whatever the actual term is risking breaking the bit? I can try that speed and two passes then.

Well, if I recall it was 7 a minute at 35000rpms so for your situation with a lower rpm you might want to go slower otherwise the bit is trying to take out more than it can handle.

Okay so I was able to try a few new settings.

What I found worked (mostly) was 6000 RPM, 20 inches per min feeds, and 1.81 inch plunge. While the first couple holes were really smooth, what I’ve found is the main issue is the cut material starts going up the length of the bit, eventually stopping the bit from going down all the way. I’m thinking it’s because of the number of flutes that this bit has, is there any other reason to have this issue of material buildup?

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