Problem with a deep cut

I’m attempting to cut out a card tray for a board game and everything works fine for the first 1" of the pocket cut, then on the next layer it attempts to cut about 1/2" all at once. Any ideas on what might be happening here?

Attaching the Carbide Create file.

CardBox.c2d (6.4 KB)

Thanks for any assistance.

Slotting is difficult. It’s best to avoid it where and when you can. When you have to do it, check the machine out mechanically, esp. the belt tension.

Add geometry around the perimeter, once for chip clearance and again for diameter and a half, and cut as a pocket down to tab depth, then you can cut the profile as a finishing pass.


I opened your file and I’m a little confused looking at the single (active_ operation that only cuts a shallow slot (1/4") deep…not really aligned with your problem that you stated (above). As Will says, slotting is difficult because the chip (sawdust) has a problem to get out causing a problem. A slot wider than the cutter will help, along with pausing the job to remove the chips…NOT a great fix, but it can work.

So, did you post the wrong file?

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I checked the file I uploaded and something must have happened to it.
‘Toolpath 4’ was the other 8 rectangles on there cut as a pocket to 1.5" deep. The slot is just a marker for me to cut the piece out with a saw after carving it and hasn’t been a problem (I should probably just set it to be like 1/16 deep or so).

Looking at the gcode file the depths looks correct, but after the Z-25.400 depth, what I think is happening is that Z goes up hits the end stop, then goes back down much farther than it’s supposed to. The display in carbide motion said Z was -26.670, but it actually was much deeper than that.

So the segment of gcode at this point looks like…


Reading that segment of the gcode file, it moves the cutter up to +5mm, then moves to the center of the pocket it is cutting. I have no idea what the G0 on a line by itself is meaning to do (could this be the problem?), then moves down to where I expect for the next layer.

It wouldn’t let me upload 2 attachments on the original post, so I’ll try to upload the .nc file on this reply. (913.3 KB)

Yeah, that’s going to be a tough cut to make as it’s laid out w/ the endmills which you’re using — add geometry, cut as pockets where possible, and consider using an endmill w/ longer flutes.

I guess you are new to this machine…

Your machine has 3.0 inches of travel, and a router that can slide up and down to clear your setup, and an end mill that can slide up into (and out of) the router collet, EDIT: And you need to set your retract height!.

This is a balancing game that the operator plays during programming and setup.

If the balance (of all the above items) isn’t right, the machine will travel too HIGH or LOW and lost its location and either go too deep (99%) or not deep enough (1%) into your work. It sounds like you are hitting the upper travel limit of the machine. THIS is what yo need to adjust. Without a photo of your setup, I can’t offer WHAT needs to be adjusted, but I think you NOW have an idea what needs to be fixed.


This is then also impacted by where you set the clearance and retract planes in fusion360. If they’re too high, you can cause this too.

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