Same thing happened when I did my spoil board, and I forgot about it.
I created a design to route out a rounded rectangle in the center of my work piece. The 0,0 is set to the lower left. Created the design in Vcarve Desktop and exported the GCODE.
Lined up X,Y,Z with my bitzero and the 1/4" end mill that came with my machine. Inserted the 1 1/4" surfacing bit and re-zeroed Z.
Hit start on the job, and it ended up being offset to the left quite a bit and not centered in the work piece. Any ideas what I’m doing wrong? I’ve uploaded to pics to show what I mean. One is the actual cut on my work piece, the other is what the design looks like in Vcarve. Thanks in advance for any help!
I’m saving the toothpaths with Vcarve to Shapeoko (inch) (*.gcode). This setting has worked for all other toolpaths I’ve done for drilling holes or vcarving, so I don’t believe it to be a conversion error.
I then open the GCODE with Carbide Motion and run it there.
Brand new machine. Just did some vcarving with it this morning, and drilled holes in 10 cribbage boards that lined up perfectly. I don’t believe there to be any slop in the machine. Watched the job start and progress (and immediately regretted not attaching the sweepy boot!) and did not see any kind of sticking or anything being stuck.
Oddly, the same exact issue happened when I used the 1 1/4" surfacing bit to surface my MDF waste board.
Or delibertately set the Z at + 1 inch above the work and watch it air cut first. That will tell you if it’s machine slippage or a toolpath / zero issue.
I’ve watched quite a few air cutting toolpaths before lowering Z depth to actually cut.
Or were they ? I wonder if Tim just stopped the cut before completion, and this is what we are seeing at the bottom of that capture (i.e. not a slip of the Y axis but just the cut interrupted before it went through the final round around the pocket, which would resulted in a pocket of the right shape, just shifted to the left by approximately the cutter diameter, from the looks of it?)
@tjandt did you double-check the declared diameter of the tool in the tool database in VCarve? That would not explain the shift, but since you mention you have the problem with that cutter only…worth a check.
Given that the shape and uniformity of the pocket is ‘as designed’, just that the starting XY is not as intended, it feels to me that there is a static setting/error rather than a mechanical slippage…
XY reference is not ‘on the lower left corner’ of the material when zeros were set on the machine
VCarve is somehow introducing an offset in the job setup - might seem odd, but I have seen this behaviour when the dreaded 600mm max (non-Pro) size is used for the stock. I set the max size to 599, re-calculate all and the issue is resolved (have mentioned this in their forums) - and the ‘offending offset’ never shows up in the VCarve Job Setup settings
If using the probe for setting XY zero, does the size of the cutter introduce some bug/error and it is reporting the incorrect ‘detected zero’ when finished probing?
Does Camotics, UGS or similar show a correctly rendered, and positioned job? The above mention of running an air cut still includes the potential for on-machine errors in XY position - Camotics preview would remove this unknown from the investigation
The JOB’s XY offset is in inches, the GRBL sender/machine is using mm, but only during position to the XY zero. Carbide Motion and GRBL is set to absolute coordinates, which would make this seem unlikely (the whole cut would be 1/25.4 scale were it so)
A further thought - if when setting XY zero you are exceeding the X and/or Y limits on the machine, then if you perform a reset ($H in MDI or machine power cycle), the ‘intended XY zero’ and the actual could differ - you would know this had happened as the steppers would have complained during zeroing…
I feel compelled to help a man who is holding a glass of real ale in his profile picture… even though I don’t have a shapeoko.
The only thing I can think of is that if it is exactly 1 inch out of whack (it might not be), then that’s the difference between the endmill you used to zero on the origin and the endmill you used to cut the project with. I never zero in the corners because I could never figure out if the edge of the endmill or the centre of the endmill was supposed to be at the zero point. So if it is the edge, then there’s your difference. If not, then… well… greater minds and all that.
I suspect there has to be some kind of bug in using the 1 1/4" bit.
I redid the toolpath with a 5/8" router bit and it worked perfectly.
Unfortunately, I do not have the original G-Code, as it was overwritten when I switched to the 5/8" bit. I will do some more testing next time I have to resurface a waste board.
