RE:
Instructions:
Calibrate Z.
Use the display to raise Z to around 50-60 mm and take your measurements.
(See image)
RE: Different Z lead screw travel between MK4S upgrade screws and Core One kit — 2 mm mismatch
Instructions:
Calibrate Z.
Use the display to raise Z to around 50-60 mm and take your measurements.
The comment in the image, "gap will increase as you go higher", is important. There may also be a fixed left vs. right difference due to tolerances in the frame and chassis. To separate it from the effect of unmatched thread pitch, I would do this measurement twice, at two different heights of the bed, say 10 mm and 110 mm below the nozzle. Then the change in the left vs. right discrepancy over 100 mm travel can be determined.
RE: Different Z lead screw travel between MK4S upgrade screws and Core One kit — 2 mm mismatch
That approach is good for the front 2, but not any good for the rear leadscrew.
RE: Different Z lead screw travel between MK4S upgrade screws and Core One kit — 2 mm mismatch
There is another common and related complaint that seems to fit this thread. That is loud and scarry rubbing and vibrational sounds the core one produces when tranvsersing the full range of the Z-axis.
In my case, I was attempting to groom my mk4s to coreone+ upgrade to eleminate those noises when I noticed the front lead screws were tiled backwards with the bed at the bottom and tilted frontwards when at the top. I didn't attempt to measure the lead screw pitchs, but it was visually obvious that the bed tilt changed over the full range of Z travel. My bed is tilting along the y axis, not the x.
To me the most likely explainatations that fit both of these observations is that the lead screws are rotating at differnet speeds, one or more of them are slipping poles, or the lead screw pitchs are not the same. In any case this definely a design or manufacturing flaw that prusa needs to address.
RE: Different Z lead screw travel between MK4S upgrade screws and Core One kit — 2 mm mismatch
That approach is good for the front 2, but not any good for the rear leadscrew.
In that case the best is a digital clinometer
RE: Different Z lead screw travel between MK4S upgrade screws and Core One kit — 2 mm mismatch
[...] I noticed the front lead screws were tiled backwards with the bed at the bottom and tilted frontwards when at the top. I didn't attempt to measure the lead screw pitchs, but it was visually obvious that the bed tilt changed over the full range of Z travel. My bed is tilting along the y axis, not the x.
To me the most likely explainatations that fit both of these observations is that the lead screws are rotating at differnet speeds, one or more of them are slipping poles, or the lead screw pitchs are not the same. In any case this definely a design or manufacturing flaw that prusa needs to address.
I think you are misinterpreting this. The tilting lead screws are due to lateral forces which the black trapezoidal nuts exert on the screws. This is a common alignment issue in the Core One, because the assembly instructions do not ensure that the lateral position of the nuts agrees with the position defined by the smooth vertical rods that guide the heatbed. But it is easily fixed:
- Drive the heatbed all the way down.
- Loosen the six M3 screws which attach the three trapezoidal nuts to the heatbed (two per nut). This lets the nuts find lateral positions that are in agreement with the smooth rods.
- Probably the lead screws will already have straightened and centered when you loosened the M3 screws. If they are still a bit slanted, center each top end with your fingers while you fasten the corresponding M3 screws again. Do not overtighten the M3 screws; the nuts are plastic (POM).
This should give you smooth Z movement without lateral strain and push on the lead screws. If the Z drive still "groans" during longer moves, it needs to be lubricated. Apply a bit of the lubricant that came with the kit to the lead screws.