Hi guys, I have a general question about my CNC machine.

CAD & CAM Tool Chain ChiliPeppr
1

Hi guys,

I have a general question about my CNC machine. It has worked great for the past couple of months, but the other day in the middle of a job, one of my two Y-axis motors stopped driving the lead screw. After canceling, I tried to jog the Y-axis but both motors would only spin together in one direction. While jogging the other direction the same motor does not spin. I read around it looked like a wiring or noise issue, but after re-wiring and shielding I got the same issue. I also modified my TinyG settings to no avail. Does anyone have any knowledge about this? Is the motor or TinyG blown?

I am running the following:
TinyG v8 (No external motor drivers)
Openbuilds NEMA 23s
24v 10a Power Supply

Thanks!

2

I think you should first unmount stepper motors from the machine and check if they move correctly when jogging. Additionally you can verify coil resistance, which should be around few Ohms for each motor coil A1-A2 and B1-B2 and infinite between A-B wires. I think most likely one of your drivers could get burnt out.

3

I had a similar issue and after much investigation and frustration it turned out one of the wires from the TinyG to one of the motors had broken in the shielding and was making intermittent contact. Effectively looked like the motor coil burned out.

4

Thanks for the quick responses guys.

I measured coil resistance, and it read around 1 ohm on each coil. There were no shorts between them.

I plugged in my X motor into where the second Y motor was and was able to replicate the issue. Upon further inspection, no matter what direction the motor is jogged, it always goes right. Since I have tried different wires and motors, does this mean the driver burnt out?

5

Try reconnect motor to one of other tinyg drivers. This way you should be able to see whether the problem is related to motor or driver.

6

We swapped motors and it definitely looks like a board issue. I don’t see how this happened though, as the board was enclosed and never overheated based on the temp sensors in the enclosure. Thanks again for the troubleshooting help.

7

The output stage of the motor driver device is typically an “H” confiuguration, two FETs on for current in direction 1, the other two on for current in direction. From your description, sounds like a FET ,may have failed in one leg of the H.
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