Y-axis calibration or bad alignment or ?

We’ve had our LulzBot Mini for over a year, been great up till now. As you can see from the photos, there seems to be an issue in the y-axis direction - front to back. Left/right seems fine. Doesn’t seem like it’s consistent on every row, just “churps” in the printing. I did take off the headed plate and made sure the screws underneath were snug, but don’t know where to go from here. Any input is greatly appreciated.

Also, the bottom 3-4 mm of the print recently are coming out looking melted and shiny, but I’m heating the plate to the recommended 100 C or whatever for HIPS. See how the model in the top photo pulled up from the base (right-hand side).


Have you checked the pulley on the Y stepper? If it slips a little, it could do that. Belt tension being a little loose might do it too…