Laser not moving in X axis direction

I’ve been having intermittent issues with my Rabbit laser running LB. During some projects, it will stop moving in the X axis even though the Ruida controller shows it moving along the X axis. See below for a demo video.

The X axis does work at times and some cuts complete successfully, and some fail dramatically (see below).

If the X axis belt is not moving, which seems to be the case, then:

  • Something has firmly jammed the motion
  • The motor pulley is loose
  • The motor isn’t turning

Turn the machine off and move the laser head by hand along the gantry. It should move smoothly without any jerks or hesitation.

Look for a loose screw securing the belt pulley to the X axis motor shaft. This will be almost impossible to see, because it will likely be inside the toothed section of the pulley, so use a bright light and move the head slowly while trying to find it.

Those aren’t revealing anything, then things get interesting.

If you have used the laser for a rotary device- check to be sure it is disabled. Otherwise, it might be wiring to the driver or the driver itself. Drivers are the thin black boxes in the electronics bay of your laser.

Tried that and didn’t notice any resistance or anything impeding the belts.
We switched the gecko connectiosn (x ↔ y) and I also opened the side of the cabinet (thinking they may be overheating). Have not had the issue since. Do you think an overheating gecko could cause that problem?

A classic Heisenbug, cured by a laying-on of hands!

After you eliminate a mechanical jam and the odd loose screw, then what’s left is the motor or driver.

Or, perhaps, the wiring in between, as simple as a loose screw locking a ferrule into the connectors. Give them all a touch of the screwdriver to make sure they’re snug.

My rule of thumb: if the drivers are hot to the touch, they’re too hot. I replaced the ineffective fan in the equipment bay of my laser with a tangential blower:

That mostly reduced the noise level, but if the equipment bay in your laser doesn’t have good air circulation, definitely fix that.

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I really have a love/hate relationship with Mr. Heisenbug :laughing:. One other thing I wanted to mention, since you brought up heat & cooling. The steppers on my OMTECH 50W (NEMA-23’s) were running very hot. I discovered that the current settings on the drivers were higher than what the 23’s were spec’d for. After I set them to the next lower current setting they ran as cool as a cucumber, with no detrimental effect on the machine’s operation. It might be something for the OP to look into.

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