Originally Posted by
highoctanecnc
It looks to me like your motors are stalling. I tested your code in UCCNC controller and it previewed without a problem. So, that means the code is good, at least if you're using a controller that interprets the code the way UCCNC does.
Does your controller have an on-screen preview? If so, take a look at the preview. If it looks right, this is likely not a controller problem and would point more toward the stalling possibility.
If it is stalling due to lack of motor torque (for one of several possible reasons), running the mandala.txt file at a slower speed will give you an indication of that. Although, there should not have been much load on the machine at such a small per-pass depth and 55 IPM.
Before you look into all the possible reasons it could be stalling, you could rule out any G-Code interpretation problems by running a simple test square. I have attached a test file to cut a 4" square with the bit on the center line (so it will come out a little smaller than 4"). Try cutting this and see how it does. Then report the results back here. If it didn't cut well, we can proceed to diagnose the stalling.
By the way, did you hear the motors stall at any point while it was cutting?
Also, your control signals could be noisy (electrical interference). Or, your drivers could be susceptible to noise.
Are your motors wired bipolar series, bipolar parallel, or unipolar?