Initial Table/Bed Alignment Offsets

So, still very much a newbie here, I apologize for my learning mode. Since I’ve discovered that my table alignment is not quite perfect, rather off by a few thousandths of a inch, is there a way to offset the zero point alignment of the laser, in the software, for the “Absolute Coordinates” setting? I only want to insure that “zero” is truly zero. Yes, I know the “Origin” button/location might be able to do a similar thing but I’d rather fix the absolute part first without have to buy a different table or mounting surface and risk making the same error once again. Thank in advance for any thoughts and yes, I will read and reply…of course!

Usually, you do not rely on any external marking. You have a true zero position after homing. Most people mount a mechanical stop / angle bracket to that position to align objects to that position.

Though, I would not rely too much on that either. Absolute coordinates have very few use cases where they are beneficial, it’s typically much easier and faster to use relative positioning. Additionally, in the case of engraving at high speeds, it’s even impossible to align an object at 0,0 if you use overscanning, for example.

After homing the gantry I think marked and mounted the burn mesh to the table under it and use alignment pins to hold it in place. Same for the laser cutter itself, both aligned to the same place on the table surface. Again, using alignment pins to provide a known location. However, even though I went to extra effort to get this alignment just right, I’m off by a few thousandths of an inch.
So i was hoping there’s a software solution to correct the mechanical to the actual position. Simple offset for the home position is all that’s needed.

A slight adjustment to the Home position switches, or pull-off distance parameter $27, should cover that error.

Curious, with a maybe 0.1mm dot size, is that effort really worth the trouble?

You did not mention the error in the alignment between the burn mesh and the laser frame. Are the sides parallel? Are both perfectly squared?

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Check out workspace coordinate offsets. If it’s a grbl firmware, you can move to your desired location, send G10 L20 P1 X0 Y0 followed by $10=0 and then you have a new offset to the machine origin.

Though, I don’t think it is worth the effort if you are dealing with thousands of an inch. Those mechanics are not made to be that exact, and you will have drift etc. and you would need to do this again once in a while. I don’t see why such precision is required at all :wink:

Well, I thought they were perfectly squared. But apparently my calibrated eyeballs didn’t seem to be in perfect alignment lol.

I was initially dealing with burn tolerances of +- .0005 and the laser cutter was indeed handling that!

Well. I was dealing with those tolerances in order to get a wooden gear box to operate perfectly. This was created to run four marble-runs, simultaneously via a dc motor. The gear box was completed and operates just as it should. I’ve not yet unboxed the marble runs to interconnect them to this gear mechanism, so the final test has yet to be performed.