I posted the following on Facebook, but I’m repeating it here in hopes of getting help in solving this problem:
Now that I have my LongMill assembled with a working controller, I can start making the necessary adjustments…
The X and Y movement seems fine, but I’m having trouble with the Z motion. I’ve made several attempts at a simple sign for my grandsons, working in MDF (much better than pine ). It simply says “Ben and Alex’s” / “Room” on 2 lines.
The first time after the first couple of letters, the depth of cut started becoming more shallow; I stopped it when it was cutting in the air.
Next time after the first couple of letters vertical movement was suddenly just a jerking of the carriage.
Third time after the first letter rather than move vertically to the next letter, it started reversing INTO the stock and getting stuck. After stopping the toolpath I had to jog it upwards 10mm several times to get it loose.
OBVIOUSLY something needs adjustment. What do I adjust and how?
[Andy Lee] Can you check that the two pulleys on the z axis are tight and the z axis motor cable is secure?
[Tom Woodhouse] And, as always, make sure your electrical connections are tight-but not too tight…(Andy Lee)
[Frank Alviani] The pulley on the stepper motor was a little loose, so I tightened both set screws. The connector to the stepper itself was tight.
Good news when trying the sign again: The letter depths were correct and consistent.
Bad news: it got through “Ben and Ale” when it went up too far and stayed there. The set screws were still tight when I checked.
[Frank Alviani] Followup: I made an almost identical file in Vectric Desktop, using the same fonts. When I tried to carve it from UGS, it did “Ben and” and stopped moving on the final d. Different code, but the cuts looked the same up to the last letter. The pulleys were tight on the shafts.