Inventables Community Forum

1/16" upcut bit keeps breaking when cutting acrylic. Help!

I keep breaking my 1/16" upcut bits when cutting acrylic. The 1/8" ones are fine, but the tabs are huge and poorer definition. I’m using the recommended settings, but maybe I can change them. Does anyone else have a carvey and know what setting to use?

Thanks in advance

Go slower, those 1/16" bits are tiny and fragile.

Cut less per pass. Simply slowing down may cause acrylic to melt to the bit.

What do you do if the acrylic is melting to the bit? Thanks!

Speed up you would be going to slow.

I have the RPM on the router at 6 already should. Should I adjust and of the feed rates or something different? Thanks!

I never run mine over 1. You need to speed up the feed rate so it moves faster and take less of a depth of cut.

For acrylic slow spindle rpm, shallow cuts at fast feed rates.
Also the less flutes in the bit the better.
Type of acrylic also makes a big difference. The paper coated stuff is best. The plastic film coated stuff is brittle and melts easier. It is best to spend the little extra and get better results.

Thanks Mark. Is there a specific 1/16th and 1/8th bit and feed rate that you could recommend? Thanks!

I have only used V bits and 1/8"" inch bits on acrylic. With 2 flute 1/8 bit I cut at 50 ipm 12 plunge and .05 doc.
For the v bit I used 30° at 60 rpm single pass 0.006 deep to etch for edge lit night light.
The 1/16th bits I have are like a carbide burr (multi flute upcut) and suspect would not do well with a acrylic and have never tried. However they did surprise me on plywood.

I have notices if you run at 70% feed rate it cuts and runs better

If you want to cut as fast as you can without snapping bits, I highly recommend checking out G-Wizzard Calculator by CNC Cookbook. They have a free 30 day trial. For hobbyist you can buy a one year license ($79) that will give you full functionality for a year. After the year the calculator cuts back maximum power to hobby machines only - which is all you need for an X-Carve. I’ve found that once you have the calculator set up correctly for your machine it will provide the best speeds and feeds for just about any material. I have not snapped any bits since using this tool. I can usually go a little faster than the calculator suggests, but usually not by much.

For the record, I am not associated with CNC Cookbook, but I highly recommend G-Wizzard, especially if you buy pricey bits like I do.