MK4S - Circular Prints Failing
Hi All,
as you can see from this image, when printing any circles on my MK4S, which has recently been upgraded from a MK4, has suddenly started printing like the image below.
I have re-calibrated the gearbox cover and also checked the idler arm tension.
This filament isn’t that old and works fine on my other PRUSA MK4 (not yet upgraded to the ‘S’). The issue occurs on any board type, any filament (all PETG) and using generic PRUSAMENT Slicer setting - nothing changed.
Any suggestions?
RE: MK4S - Circular Prints Failing
That looks to me like poor adhesion to the bed and/or printing too fast. For reasons of inertia, the filament has a tendency to keep an straight trajectory. When we draw a circle, if the adhesion to the bed isn’t good enough or the speed is excessive, the thread of filament strays from the curve and takes the shortest path, as in the picture. You may argue that on a MK4S printer, the Z offset of the first layer shouldn’t be an issue. In real life this isn’t always the case, because of imperfect calibration of the load cell for different reasons. Even if the Z offset is correct, when the bed isn’t spotless, adhesion may become poor.
To be fair, I don’t see signals of a dirty bed on that picture. Besides, if the filament is PETG, adhesion shouldn’t be a problem even on a textured bed, provided that the Z offset of the first layer is correct,
If you have no problems with your other MK4 printing with the same settings, it looks like a Z offset problem. Nevertheless, I’d try to use adhesive and/or printing slower and see what happens.