Tool breaks in the middle of job


I am trying to cut this piece with a Nomad. The piece is part of a DXF file that I acquired (Brian Law’s first clock). Pawl.mcf (39.3 KB)

This is not a problem of zeroing Z. The top part of the piece is cut without issues.

With my settings, MeshCAM generates code that breaks the tool in the middle of the job. I can see why with bCNC. There are two sets of toolpath curves and each set has a depth equal to half the stock height. The deeper set is offset with regard to the first (Why?). When the second set is being cut, the tool plunges and then moves horizontally but there is still too much material around it and the tool breaks.

How can I correct this problem? Is it a question of the MeshCAM parameters I’m using? Is it a problem with the DXF files? Or am I missing something obvious?

Note: I scaled the DXF file by a factor of 0.5 before feeding it to MeshCAM.



When I load up that mcf and look, it looks like the following. I don’t see where it does a full depth cut offset in MeshCAM or in CAMotics. It does do a pencil finish at full depth, but that should be where the earlier roughing and waterlines already cleared it out. What depths (in mm) are you seeing? I could search for it in the gcode if I had a better idea what I was looking for.

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Thank you, Mark.

These are my toolpath settings (I don’t know whether the mcf file shows them or not):

This is the toolpath MeshCAM 6 built 27 64 bit is generating with the previous setting. The geometry is 6mm deep:

This is the generated G-Code: (43.6 KB)

The break happens in line 1317.

I thought the settings came with the mcf, but they didn’t match what you show here. Those are tiny bits. I think you’re gonna want to do a roughing pass with something bigger. Like a 3mm square end.

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Perhaps the tool path looks like that because of the tool definition. The taper or the shoulder?

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You nailed it Mark! I made a mistake in the tool definition, I used a flute length of 3mm, it should have been 8mm. Thanks for your help!