Mk4 upgrade strange linear lines on prints
Hi!
So yesterday I upgraded my mk3s+ to mk4. Everything went smoth, all tests passed green. But first benchy came out pretty bad. There are strange horizontal thin lines allaround the obejcts (lots of benchys - see pictures). Printed also presliced one from usb, lines are still there but not so much obvius. I contacted online support, but we didn't came very long, last advice was "continue with testing" 😐 . I run tests again, again all green. As per prusa support (from picture) printer and nextruder seems to be correctly put together. I use dry prusament, sliced with latest prusaslicer and latest firmware. Thank you for time and suggestions!
RE: Mk4 upgrade strange linear lines on prints
How smooth is the z axis movement - were the lead screws nicely central when you popped the tops on?
RE: Mk4 upgrade strange linear lines on prints
Hi, tnx for answer. You are probably on something...i did revision of bolt tightness on bolts that holds z bearings, and it seems that they were to tight. Did couple of test prints after and there is dramatic improvement in quality. Still some little imperfections but much better. Thank you!
RE: Mk4 upgrade strange linear lines on prints
I’m just happy to have pointed you into the right direction 😁
RE: Mk4 upgrade strange linear lines on prints
In addition to various other problems with our factory assembled mk4 we have just started having similar linear banding. Our maintenance guy...not saying who that is... tightened a variety of z axis bolts. Hoping that this is the issue that you guys are referring to.
Which bolts were it that seemed to be causing your issue? The 4 outer ones on the outside of the bearing for each smooth rod?
Thanks!
RE: Mk4 upgrade strange linear lines on prints
Hi! So to elaborate a bit more... in the end I rebuild complete Z axis once more, it turned out that bolts that compress Z axis bearings are probably not the culprit. Even in pretty tight configuration movement over smooth rods were ok. What I found out is that in step 11 of Z axis assembly if you don't put Z tops on before centering threaded rods the whole X axis gantry will be tilting slightly to the frame because of the force of the X-holder tool. So what I did, I put z tops on before centering threaded rods, so they are centered in their final position. When powered on, I did Z axis calibration, that lowered X axis to about 2-3 mm above bed, loosened trapezoidal nuts, wiggled a bit whole x- axis and tightened trapezoidal nuts just barely, not to deform them. After that, another Z-axis calibration, and so far problems are gone.
Regards,
Peter
RE: Mk4 upgrade strange linear lines on prints
Ag magic, glad you got sorted out mate
RE: Mk4 upgrade strange linear lines on prints
@Peter_B
Thank you for the clarification. I had decided to rebuild the Z axis as well and actually ended up doing the centering with the "z tops" on just because I was having trouble removing them without removing the entire z and x axis. So inadvertently did what you recommended. I added the step of lowering the z axis and wiggling the z drive screws with trap nuts loosened and then redoing z calibration. Not sure if it was that or that in combination with other things I did but the z banding was gone and other print defects improved as well, even on a relatively difficult print. It's only been one print this far but fingers crossed that was the issue(s).
Thanks for your input!