Part way through cut, machine decides to dig in to sidewall then goes haywire

Hi there,

I am new to my x-carve. I am trying to mill a pretty simple shape out of aluminum. I have done it a couple of time successfully but am still having issues.

it will cut fine for some time, then all of a sudden, it seems as though the bit digs into the sidewall, and once it gets hung up there for a sec, it actually seems to start going in reverse, but following the path backwards. but at this point, it is off of the actual path ans it trying to cut new material.

Here is a photo for some reference:

i thought that i was getting thermal throttling, so i went through the process of setting my pots. i basically had the x-carve move back and forth in each of the axis, setting the pots, finding the limits that caused thermal throttling, and then setting in the middle. these settings were able to run for at least 10 minutes without any issues so i deemed them proper settings. the voltage for each pot is in the 1.5 volt range. I have nema 17 motors currently.

cut settings as follows:
75 in/minute
8 in/min plunge rate
.005" doc

as mentioned, i have completed cuts before.

I was using a 12 volt psu which i understand can run the motors hotter, so i switched to a 24 volt, 500 watt psu now, hoping that it would help prevent thermal throttling.

any help correcting this is greatly appreciated. tearing up aluminum is no fun.


I had similar issues. Adding a fan blowing on the drivers and a shielded USB cable fixed my issues.

THe machine does not return to zero. although i do not think i have that option turned on. I am not using homing switches as my z-axis acme screw seems to be bent and gets caught on the z-axis maker slide before getting all the way retracted.

I have a 120mm fan mounted on my controller enclosure blowing air directly down onto the gshield. i guess i could look into getting a shielded USB cable. not sure how to tell if my current USB cable is shielded or not.

try milling a slot wider than the bit’s diameter. The chips need to go somewhere. Milling a ‘deep’ slot in alu without accounting for that will always give you troubles.

Good CAM software will have an option for that. But the cheap trick is to offset the original profile to 180% or so, and pocket out the area between the original and newly created outline.

I meant that it does not attempt to return to zero. not that it goes but doesnt go to the right spot.

I just attempted this cut again. I slowed the feed rate to 50 in/min, and it almost made it through. I think that an error occurred though due to my misjudgment of material thickness and offset, and my tabs were too deep, therefore, not getting created before breaking through the material.

I also noticed that the machine seemed to “struggle” in some areas and not others, which i think is indicating that the spindle is not square enough to the wasteboard and that it is taking more material in some areas than thought. i will attempt to square it up better and also correct my tab issue and try again.

I would also like to try the pocketing method, but i need to learn another cam software(i am currently just using easel). I also need to get an 1/8" bit so that i am not wasting so much material. pocketing with my current 1/4" bit will waste a lot of material.

thank you for the help so far, i will update this post as i progress and hopefully become successful.

OK, so to report back on my issue, i bought a square and squared up the spindle. It was off a little before. Once i did that, i successfully cut 2 pieces without any issues.

There is a audible difference now. it basically has a uniform sound throughout the whole pass, where as before, it definitely got louder and sounded rougher as it moved in one direction.

Thanks everyone for the help and suggestions.

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