I just finished up my extruded aluminum style CNC router. A little background on this machine that I designed:

V bearing guides with Fixed and Eccentric bushings.
1/2"-10 Acme rods (48" Y, 36" X, 12" Z).
Anti-backlash delrin ACME nut purchased from McMaster.
Machined steel plates for motor mounts, ACME nut mount, gantry and bearing mounts
10 Series 80/20 Extrusion. 2"x4" Gantry beam and bearing rails with 2"x1" table supports.
Gecko G540 w/ 4 NEMA 23 381oz/in motors from Automation Technologies
UC100 Motion Controller
UCCNC Software
No homing or limit switches installed
Shielded wire (I believe they are grounded to the plug end at the G540, I will be checking tonight. I do not believe I have the motor case grounded)


If you want more details on my machine I would be happy to provide it but my design is based on the thousands of other extruded aluminum machines out there. I have my A-Axis slaved to my X-Axis to move the Gantry.

Setting up the machine, I have squared the gantry by measuring the extended length of each Gantry carriage and moving each axis individually until they are equal. This method seems to work fairly well for squaring the Gantry. However, I have noticed that if I jog the machine at a higher feedrate the X-Axis seems to stick and sometimes even cause the motor to stall. I have slowed down the feed rate and that has improved this problem but it has not completely resolved the issue. After running a program, I find that the gantry can be out of square by 1/2"-3/4". The slower the feed rate, the smaller this gap tends to be. I have slowed the feedrate down to a point now where I am starting to burn my wood with brand new bits and I still have this square issue.

This is causing major problems in trying to achieve accurate results and I am no where close to repeatable. I am trying to figure out what all can be contributing to this step loss and out of square condition that results. I am still learning so there are probably a few basic steps I am missing. I have tried using the Trim function on the G540 but I dont really understand what everyone on the forums and youtube are saying about where this should be set. I have also checked my UCCNC axis settings to make sure my X and A have the same configurations. My guess is the issue is either in the mechanical side or on the wiring/motor side but I still have no idea where to begin to troubleshoot those issues. Any advice or direction would be much appreciated.

Thanks.