Cutting Plastic

[Ron Johnson]

I’m cutting some Polypropylene ½” & ¾”. Using a ¼” up cutter & 27,000 rpm trim router. The plastic melts & leaves a lot in the hole, so I have to stop & reverse the cutting to clear it out. I cutting slow & cant speed it up much more.

Anyone know of a bit or what to cut this.

Ron

[Rob Wright]

Ron,

I have a small home built CNC. I have been re-making a number of the parts of the CNC now that it is up and running. My bearing mounts, motor mounts, and spiders are all being re-made with poly cutting boards. I have a variable speed trim router and turn it down as far as it goes (15K RPM). I can only cut at 15 ipm (travel at 20 ipm max) so I take very shallow cuts with the plastic. I set vcarve to calculate tool paths at 0.08" per pass. This has worked to avoid melting - but I still get some. I am using a freud 1/4" spiral up cut.

Hope that helps some - Rob

[Wil Lambert]

Check out www.courmatt.com. Call them up and talk with Greg and he will set you up with the correct bit for this. Plastic cutting uses a single lip upshear or a single lip straight cutter. Courmatt has been my supplier for the past few years and I have not been let down. Good luck, Wil

[Ed Lang]

Your choices are....

fewer flutes on the cutter
slower spindle speed
faster feed rate

goodluck.