The Problem
My CNC machine is stopping & starting between points in G-code on curves. This is making my machine shutter. I noticed it while cutting out of MDF a 30” tall letter “P” for my grandson’s bedroom (Paxton is his name). The g-code has a lot of little short straight runs to create a curve in the letter “P”. I notices a small jumping movement (or shutter, or stop/start movement) at every point, and there are a lot of points. So here is what I found out by reading other posts.
G64
First, my g-code has G64 which is for “constant velocity mode”. See line N100 in G-code below.
N100 G17 G20 G90 G40 G80 G64 G49 G0 M05
Mach3
Second, my Mach3 settings that I thought might be important are shown below:
• “LookAhead” is set to 20 lines.
• Motion Mode is set to “Constant Velocity”.
• CV Feedrate is turned off (on the setting page of Mach3).
• All motors are set the same to 200 ipm, with acceleration set to a low 4 in/sec/sec.
• Nearly all my cutting is at 30 ipm feed rate, so running too fast, or too high an acceleration rate, is not the problem.
Computer
The computer used to run Mach3 is dedicated to just the CNC machine. It is not connected to the internet, no anti-virus, no other program running. Only Mach3 software is loaded on it.
Need help
The quality of the cuts is excellent. The CNC machine is doing what it is told to do. But I would like to get rid of whatever is causing the machine to stop/start at every point. I believe there is something in the Mach3 setup or G-Code that is causing this and I do not know what to look for next.
Thanks for any suggestions.
Mike