HI All, on my Y1200 home build machine cutting a large rectangle it is slightly off square, maybe 1mm over 1000mm I have tried to dial it in mechanically and without serious modifications to the machine I just cannot seem to get any better. I just wondered had anyone had any suggestions, can it be fixed in software similar to the software backlash fix. Thanks in advance. Alan
I don’t know this machine, but to be off square, I would have thought the gantry may be slightly out of square. If you need very accurate cutting i would invest in a large set square maybe 50mm x 50mm to check it.
Do you have more than one motor driving X? Do you have more than one motor driving Y?
Hi Jeff, yea its 2 identical steppers on the x axis, driving two belts onto open builds gantry plates. I am pretty sure the problem is mechanical ie the actual gantry is not dead square to the rails. I may try and make some kind of mechanical micro adjustment plate to dial it in a bit better, with a view to changing the rails and gantry rollers to a linear bearing setup I think that might ride more square.
Having two motors driving an axis has its potential complications inclusive of the possibility that the motors are not driven identically or they differ in their mechanical properties ever so slightly. So this is another consideration on your quest in finding the cause. You’re also in for a surprise if / when one of the two motors fails.
Now, on my 4x8 CNC mill with a solid steel gantry with the spindle, Z Stepper, and Y Stepper along for the ride, the X axis on that machine is driven by two motors simultaneously. But for a laser machine having light weight components, it is better to have only one motor driving X and one motor driving Y.
Are you sure? (two motors driving x?)
On my laser, X is the motor on the gantry (moving the head left and right):
Y is the motor in the back that moves the head toward and away:
Yep two motors on the x and one on the y
I trust you (your video doesn’t really show the motors driving X). The orientation of your gantry is uncommon. I see that the path of your laser is persistently in the front of your machine which increases the risk of operating the machine without a closed lid.
As far as the rails being square… That’s a lot of T Slot Framing Extrusion which means a lot of places for all of those gussets to be slightly off, become loose, or move while adjusting other ones.
I have installed a magnetic switch on the lid since recording that video as I did see the danger. I agree about the T slot and think that is def a weakness in accuracy department. However on the plus side the machine has more than paid for itself selling items on my ebay store. So time to invest a little more. 
Thanks for the comments
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.