I am surfacing a new spoil board using a 2.75" surfacing bit and a standard raster pattern. When the spindle is at the far right and moves +Y, the bit digs into the surface leaving a semi-circle ~0.25mm ( 0.01") deep. This doesn’t happen on the left hand side.
It would indicated to me that the gantry on the right side is loose, but I’ve tightened everything. Any ideas?
You might have a twist in your gantry beam on the right end. One possible cause is just the 80-20 rail is twisted. Another is that the end plate might be pushing the linear rail away from the surface a bit where the rail crosses it.
I had to shim my rails to he rid of the twist and bow on the gantry.
– eric
Even if you think everything is tight, my usual advice here is: put the spindle where the problem happens, grab it by the nose, and wiggle it. If you can move it by hand, find out why and tighten it. For best results, your motors should be active (so they’re holding position) and the spindle empty and not rotating (duh).
Smart. Doing that test, there is play in the motor/pulley, where there is no play on the opposite side.
I pulled off the motor assembly and tightened the belt, which seemed to reduce the movement but not eliminated it. Sure enough the scalloping problem remains. The Right side still has a slight movement, whereas the Left side is rock solid. Perhaps it’s one of the linear bearings.
The right side scalloping happens even at a very slow feed speed, which would seem to rule out something loose. I just trammed the spindle, and the rest of the spoil board is perfectly flat.
Do you do a perimeter pass just wondering if that would clean up those?
I haven’t done a perimeter pass, but will with the next surfacing (clicked that setting in the aspire tool path). Probably in a week or so.
