So I accidently put my end mill right into the bed today by accident… totally my fault, I had the wrong origin on my part. However, this got me thinking. When using the bit setter, the Shapeoko basically knows where your reference zero is relative to the end mill. Since the bit setter tends to be in a fixed position, could we not also know where the bit setter is relative to the actual bed surface? What I propose is that you could calibrate the bed zero relative to the bit setter as a one-time thing like setting the home position for the bit setter. After that, when you load a program and complete your zeroing, the software can check the nc code to verify that the code isn’t going to go below the bed zero, and if so, issue a warning. This might help ward off an amateur mistake like mine!
I’m run version 636, but I believe that bounds checking is only for the X and Y? Useful for sure, but it’s the Z where personally I’m most likely to make the mistake. I believe adding a bounds check for Z would require an additional calibration step to tell the machine where the surface of the bed is located relative to some known point on the machine (ideally the bit setter a that measures the current tool length).
Bounds check is for X, Y, and Z
But it’s not checking if you’ll hit the table, it’s checking if the Z axis will hit it’s limit.
But yes, if CM knew the offset from the bitsetter to the table, it could warn you if the toolpath would violate it.
It may even be able to measure the table during the process if you have the BitZero.
I agree. Hopefully this would also resolve the annoying (and random) pop up warning that a program will plunge below the bottom of a project. I get random warnings that a job will plunge below the material thickness - not every time running the same job. Most recently while carving .0625 (1/16”) deep advanced v-carve in .5 (1/2”) material.
Makes no sense and I’m frustrated ignoring the warning while wondering if I missed something in setup. Especially after running a test piece and then getting ready to run the actual job with the expensive material. Always using stock top for the z zero.
Of course, carving a full depth cut I want to go below the material thickness - that’s why carbide put the “sacrificial” surface on the table. I always use a spoil board under my material to keep the table looking nice (so far…).
It doesn’t say “bottom of project” or “below material thickness”, it says…
Which means the lowest Z value in the toolpath is lower than the lower limit of the Z axis, with the current Z zero. This is relative to the machine limits in the Shapeoko.json file for CM, the currently set Z zero, and the min/max values of Z in the program.
Thanks. I was trying to post from memory. Needless to say, when ignoring the error the machine does not go beyond the machine limit. An annoyance nonetheless.
It goes beyond what it thinks is the machine limit, based on the values in the Shapeoko.json file.
Take a look, and update the values to your actual limits.
So even with calibration, a “threshold” field might be useful so minor variances in the surface height wouldn’t trigger the warning unnecessarily. In my case, I asked it to plunge 10mm into the bed. (I calibrated to the bed height, but my part origin was on the top.) I’m just looking for something that’s going to catch major errors on my part and allowing for even 3mm error would probably catch most issues but prevent gouging the aluminum bed. Anyway, feature request please!
I think this falls into the “Due Diligence” part of running a CNC.
I’ve had customers in the past that wanted me to make their work process completely “foolproof” so they could hire unskilled labor to do a skilled job. Having spent a lot of time learning several occupations (Pattern/model making, cabinet making, CAD/CAM, software development…) that didn’t sit too well.
The bounds checker lets you know if the machine will hit a limit.
Double check your Z heights when you set up the job. The controller software (CM) lets you know the min/max axis values in the toolpath. It doesn’t take much time to touch off the tool to your table/spoilboard and look at the Z position to make sure you won’t crash.
The first freelance coding job I ever had was from a guy that said, “I don’t know how to do it but I know it’s not hard”
I was young and respectful at the time. Now I would just laugh in his face.
Just wanted to add my valueless 2 cents. We ran into this on a fairly consistent basis. However, 1’s and 0’s don’t lie. Our team for our CNC ops includes a graphic designer/3D Modeler, mechanical engineer, and a machine operator. Admittedly, my initial impression of this company and my current experience are night and day. That being said, we have ran literally hundreds of prototypes through the SP5 Pro in 4x4 using a wide variety of software to produce the NC files. We use Motion to run the machine. When that warning appears? Now we shut the machine down and go find the error. We have NEVER had that popover appear in a situation in which the code was rendered properly. And in this instance, it’s going to be found in the Z axis. I guarantee it. Now, whether or not the bit will actually plunge into your wasteboards or worse? Heh, that’s the crap shoot. Depends how bad you messed up that Z axis 
The software is as solid as the input imo.
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