1/8" End Mill Load Up

Hello, I decided to try my hand at cnc crafting. Not only for myself, but, hopefully, I can get one of the grandkids interested. Recently bought a 3018 Prover and downloaded the Easel Software. I started machining my first project with 3/16" plexiglas. Into ~20 minutes of the roughing cut, the 1/8" single flute steel end mill loaded up with melted plastic. My feed rate was 10"/min, plunge rate 9"/min, depth per pass .01", and spindle speed of 9000 rpm. The cut started out fine with nice chips, but loaded up towards the end of the 20 minutes. I do not know if the end mill got dull on me and I need to use a better cutter or if the machine setting need to be changed. Any suggestions? Thanks.

I bet there is a special cutter for plexiglas. I know there are special drill bits for plastics. You may have to change your feed rate too as there is probably a sweet spot.

Plastic Cutting Router Bits -Industrial, ZrN & Spektra Coated by Amana Tool - CNC Router Bits - Industrial CNC Tooling from Amana Tool - Products

For some plastics, you can find specific bits that are designed for milling them. Other than that, typically you will want to use a single-flute endmill for acrylic running pretty fast and shallow. You will also help your self immensely if you use cast acrylic instead of extruded acrylic. Cast acrylic is easier to machine…


Brandon Parker

Thanks fellows for your replies. I am using the extruded acrylic sheet (3/16") as I had a lot of it left over from another non-cnc project. If that is the root of my problem, then I will switch and buy some cast. I will experiment some more with a different cutter, different speeds and depths. If there is someone out there with a particular cutter type and cnc settings that would work for me, I would appreciate hearing from them.

Also, is there a way to restart the roughing program without going through the whole program? In the project mentioned above, I did finish one roughing section before the cutter got gummed up. I would like to change the bit and start the roughing cut at a different section. Thanks

Gcode files are text and can be manipulated in a text editor like Notepad or Wordpad. I routinely cut and paste my files, but I don’t use Easel and I am pretty good reading Gcode. M0 is a pause. I had it in a file I ran today and the it did pause. I use UGS for sending it to the machine. It did require a button press to resume. Grbl can’t interpret all the Godes, but many of them do work.

GRBL G-Code Definitions - Carbide 3D

Get to Know Your CNC: How to Read G-Code (makezine.com)

An Introduction to M-Code and CNC Programming (thomasnet.com)

Thanks Martin, I figured I would get into the G code at some point. Looks to sooner than later! Regards, Charlie