Mach4 or Avid Controller

While running an 8 hour operation yesterday, at some point, my x zero reference point shifted approximately 8” ruining the operation.
Am running Mach4 and Aspire 11.5xx on an Avid 48x48 with their plug n play controller and spindle.
The simulation in Aspire ran perfectly so probably not Aspire or the G-code
The cutting operation was not paused at any time and it ran through to completion.
Any suggestions where to look? I have used the file before with no issue. And I did home the CNC prior to starting the cut.

Sounds like skipped steps in your stepper motor. Check your belt tension and cog wear. Also check the bearings are well greased. Then look over all the wiring connections from the controller card to the motor . Any loose or intermittent plugs can lose a lot of steps.

Pretty sure I’m losing steps. Checked calibrations and all looks good. Cutting this file in very light stepover of 4-6% and very shallow plunges less than .08 inch…
Tried cutting it again and same results just not as much inaccuracy……maybe 1&1/2” over 18 inch material along the x.
First time I’ve encountered this and it’s frustrating.

I’d suspect an intermittent wire connection, then. It only takes a bit of vibration to interrupt signals. If it only happened on deep cuts, it’d more likely be mechanical slippage. It can be tricky tracing wire problems. Take your time checking every connector. A multimeter will be your friend. Good luck.

Hey - what feed rates and rapid settings are you using? Are you using NEMA 34 motors or the smaller ones? It really looks like your axis is jamming or the motors are missing steps.

One thing to pay meticulous attention to is the belt tension. Too lose and the belts will slip, too tight and they will jam. I’ve had the latter happen and it took a call to support to figure out the issue - “belts too tight” didn’t occur to me as a possible issue :oP

Changed the belt and all is well now.
Thanks to all for advice.

I had a similar problem and it happened a couple of times. The second time it happened I knew what it was. I was vacuuming the chips and the hose got too close to the sensor. I figured the static tripped it and reset the location. Any metal object too close to the sensor would also cause this problem.

Which belt(s) need to be checked for proper tension?

It was on my “Y” motor.

The one time (so far - knock on wood) when this happened to me, I had loaded the gcode straight from the USB stick - without first copying it over to the HD. Not sure if that can really be a cause - but I now always copy to the HD before loading the gcode.


I did it once with my belt buckle on the front sensors. Now I’m pretty careful where I lean over :slight_smile: