Zero Off (Y-Axis)

Can anyone give me some advise on why my Y-Axis job Zero is off?

I have used (2) methods to set job zero.
Method #1 is using BitZero V2 to set zero.
Method #2 is using the Ø1/16" rod to set zero. When using this method I visually place the center of the Ø1/16" rod as best I can to the lower left corner of the stock.
Out of these (2) methods Bitzero works best, but it still appears to be off.

As an example, I have a piece of stock that is 5-5/8" in the Y-axis. The machined part perimeter is 5.5", so that should be 1/16" per side. Using (2) passes that should be closer to 1/32" per pass, per side.
In reality, the machine always cuts significantly more material toward the front of the machine. In the example shown in the attached image, the first pass takes off almost all the material of the front side of the stock.

Is this a programming error on my part? Or is it machine related?
I’ve attached an image and a Fusion360 file.

Sandpaper Storage Cabinet - Top-Bottom (183.7 KB)

Have you ran any calibration tests. Some times the default stepper motor steps can be shorter or longer in actual dimentional movement. This calibration error can produce results you are describing.

On the forum or wiki are the calibration setup and fix.

I wrote up a bit about calibration at:

Just to be clear the finished part is the correct size (in this case exactly 5.5").

My problem is that the toolpath doesn’t cut equal amounts of material from the front and back of the stock. In the JPG I showed in the original post, the toolpath cuts 0.100" off the front of the stock and 0.025" off the back of the stock (even though it should cut equal amounts if zeroed correctly).

I’ve tried zeroing the stock using bitzero and manually.

Is it possible that a calibration error could cause the Y-Zero to start in the incorrect location, but still machine the exact correct size?

Wouldn’t the discrepancy you describe be caused by the origin not being set as intended relative to the stock?

Yes it would.
I’ve set zero using bitzero and manually with similar results.

When I need to precisely position stock, I cut out a dogboned pocket to place it in.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.