First post newb here.
I am still putting the finishing touches on the setup, I’m having a hard time figuring out how to fix my squaring of the core. I drew a box around my work area while jogging the machine. The diagonals measure the same but the overall shape is trapezoidal.I used brass inserts to mount the base, but that leaves no room for adjustment I might remove one, fill the holes with epoxy and try to dial it in better. MDF might not be a good base material.
What controller are you using? It may be possible to correct the squareness with a homing correction factor, but it requires having 5 stepper drivers on the controller.
I’m using the jackpot 1 controller. I was able to get the trucks within 1mm of each other but getting the stop blocks aligned just right seems to be tricky. When I had everything set, I moved the stop blocks aligned up against each limit switch and backed them off just enough to be on the verge of opening/closing. After jogging the core around, I would jog it up to the limits and they wouldn’t open the connection at the same time, one would engage, then I’d have to move it .1-.2mm to get the second switch to open.
I’m going to have to do some more reading in here as my “logical” method for setting this up either isn’t working or I am nuking the “problem”
Take a look at the auto-squaring section of the Docs. You get the physical end stops within a mm or so of square, then use software tuning to fine tune things so that the machine squares itself each time you run the homing cycle. During homing the machine runs each X and Y motor independently to square things up, but outside of the homing cycle the two motors for the X axis run in lock-step, as do the two motors for the Y axis.
I don’t believe you can “jog” the two ends of the X or Y axes separately outside of the homing cycle.
Trapezoids shouldn’t be possible since there is a motor driving on each side.
The motors on either end are the same. The pulleys are the same. So the belts may be to blame. Make sure they have about the same tension. They should be snug, but don’t have to be very tight. The fiberglass should keep them from stretching much when taught. Also check the grub screws holding the pulleys on the motor shafts.
Another possibility is backlash. Jamie made a test pattern generator. The ruler will draw in both directions, so you can see backlash easily:
But just look at the machine for backlash first. And Tom is right that you only need the physical machine close and the fine tuning is done with endstops. After homing, the motors move in lockstep and you stay square for the whole job.
