Well I got my SD2 up and running after tension and replacing both step drivers with SureStepr. and made a huge difference but still had shift but now in the X. Last thing I did which fixed it the most. Was cleaning my nozzle? Not sure why but after still have shifts in Y and X with new drivers and tension I cleared my nozzle, which didn't appear to be clogged. I heard some popping. SO try cleaning nozzle. Of course I went back and leveled bed and cleaned everything again and checked voltages with both POWER and USB plugged in that made a huge difference.
So after all that and calibration I had good runs on larger diameters parts within .1MM at 50mm or 0.001" on 2" parts which was good. But on small diameters I was still .1mm-.2mm off and some with shift.
I think it is now backlash, maybe too loose, but hate to play with it more and make it worse. But I also noticed it like you at the top of my prints. Looks good but then shifts near the last few layers. to the right.
I think it could be small diameters and lack of cooling so the head drags a little. I turned off retract on new layer in SLic3r .99(new feature) which helped. But I am thinking that with small parts and my speed/accel I am getting overshoot.
Anyone have good accel numbers? I am running the stock 9000. I am thinking they are too hi and getting overshoot?
SD2 owner- Surestepr, filament holder,QUBD servo and heaters, glass bed
Print for fun and for parts for my sports cars
current car is 88 IROC