info for cutting acrylics and lexan

[Burkhardt]

.... has anyone tried using compressed air piped right at the bit (maybe an 1/8" diam or 3/16") and let run steady to cool the plastic as the bit runs around? ....

Yes, I have done that when I had to cut clear extruded acrylic sheet (which really melts easily and is a mess). See the 1/4" aluminum tube on the left. It is pinched flat to a nozzle and fed with about 20 psi.
This was for a reverse lithophane, roughing with an 1/8" end mill and finishing with a 0.025" radius ballend.

I am not sure if it is really cooling much but at least it helps clear the swarf from being re-cut. Anyway, it worked for me.

[blackhawk]

Andrew - I have been cutting a lot of acrylic and Lexan lately, mostly Lexan. I have been using an Onsrud 63-775 1/4" bit. I have a PC router and run it at 16,000 rpm. I cut 1/8" deep per pass at around 2 IPS. I have never had any problem the Lexan melting at the bit. I don't use any cooling. My edge finish is good, I wouldn't call it great. I have used an 1/8" bit in the past with success, but they will break. Stick with a 1/4" if you can, I have yet to break one of those (knock on wood).

[myxpykalix]

The guy on here who cuts alot of plastic is "Xray" and he would be the guy to get some good cutting advice from.

http://www.talkshopbot.com/forum/member.php?5242-Xray

[knight_toolworks]

Andrew - I have been cutting a lot of acrylic and Lexan lately, mostly Lexan. I have been using an Onsrud 63-775 1/4" bit. I have a PC router and run it at 16,000 rpm. I cut 1/8" deep per pass at around 2 IPS. I have never had any problem the Lexan melting at the bit. I don't use any cooling. My edge finish is good, I wouldn't call it great. I have used an 1/8" bit in the past with success, but they will break. Stick with a 1/4" if you can, I have yet to break one of those (knock on wood).

With 1/8" you need to stick with 1ps I use 1/8" a lot to keep the small parts in place. I cut upto 1/2" thick with a 1/8" bit.