Tool Path Error

I’m pretty new to CNC and have had my XL for only a few weeks. I created a new larger version of the Shapeoko tutorials clamps in Create and ran using Motion. The Motion simulation looks fine and an additional simulation in CAMotics looks good as well. However the last tool path, the profile cut, was way off its intended path. Please see the attached picture ( I can only post a single file as a new user) The profile path is cutting about a inch low but the first cut appears to be at the right bottom location then it went of course (see the grove cut on the left clamp). Any idea what is causing this path error?

Thanks, Michael

Did you hear any suspicious noise when the first pass of the profile cut began ? Since this first pass began in the right spot but then shifted, it could be a (major) belt slippage. Something must have happened when the endmill made its ways to the top, which would also explain the shallow partial cut in the upper right corner of the left clamp ? Does it match the direction of the profile cut toolpath (i.e. counter clock wise)?

Other than checking X/Y belts, if the design AND the g-code look ok…I’m not sure what else could have caused this. Were you anywhere near the X/Y cutting limits maybe ?

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Here is the c2d file

MS Larger-3.c2d (24.0 KB)

Out of curiosity I checked this c2d file, regenerated the g-code from it, and visualized the toolpath in CAMotics: it all looks ok, and indeed the profile cut is running counter-clockwise, so my bet is still that some mechanical issue happened during the first pass of the profile toolpath while cutting the top-right corner.
So if it were me, I would:

  • check belt tension (especially Y belts, assuming your stock was positioned on the machine as it appears on the picture)
  • check where the stock was fastened at the time the problem happened and whether by any chance the top of the profile cut toolpath was in a place that the cutter cannot access (Y limit)
  • rerun the same job on a piece scrap stock, same wood or MDF, and see it the same effect occurs again.
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I ran another test piece and it had the same error. I did notice an unusual sound and determined that the work piece was too far back against it’s X/Y limit (back left corner). Moving the piece towards the front center of the work area fixed it and I just successfully ran the project. Thanks for the tips and quick response. There are many, many details to considering/think thru while using these awesome machines. Michael


Good to hear. Carving clamps is kind of a rite of passage, so congrats ! :slight_smile:

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