First layer rippling/inconsistent Z height
Hello,
till today my MK4 printed almost flawlessy. But today I got a problem where I couldnt find a solution. To show my problem , I printed (PLA) a square with the size of the print bed. As you can see, on the right side the surface is very rough and uneven, but the left side is fine. I concluded that the nozzle is to close to the print bed. Since the MK4 has a Z-calibration, how is it possible that the differences between left and right side are this big? What I had also noted was the different layer width when printing a skirt. The layer width on the right side was bigger than left, looked like it was pressed more to the print bed.
I used the PrusaSlicer standard profile 0.2mm Quality and cleaned the bed with soap, warm water and isopropanol. This phenomen happens with Origianl Prusament filament and non Prusament filament, but it is much more noticable with non Prusament.
Any suggestions what can cause this issue?
Greetings
EM
RE:
It seems that the bed isn’t perfectly flat, which is almost impossible with beds made from a glass fiber board. In these conditions, even if the MK4 performs a bed mesh before printing and has automatic Z offset, the machine can’t do a perfect job when the model covers practically all the surface of the bed ( which is not a very common situation).
I did the nyloc mod on my MK3S+ and now I have minimal offsets on the 9 points corresponding to the bed screws, but the intermediate spaces between the screws have small bumps and hollows that a 7x7 bed mesh can’t compensate well enough. I know that if a print covers a significant part of the bed, the first layer won’t be consistent and I’ve learned to live with that. Maybe a new bed would improve the situation but maybe it will be even worse than the current one,
Nowadays, for printing large flat object ( stencils, for instance) I only use my other printer, a Core XY with a static bed made from a thick aluminum plate. Although not perfectly flat, it has only a minor and smooth warp, with no irregular dips and bumps, so first layers on large models are much better than with the MK3S+.
First check there are no debris, stringing, scraps or fragments under the sheet.
Then give the sheet a thorough clean; there are signs of fingerprints reducing adhesion especially around the edges.
And try again. The pressure sensor should accomodate but if it doesn't then come back with updated pictures.
Cheerio,
RE: First layer rippling/inconsistent Z height
Same problem....
RE: First layer rippling/inconsistent Z height
On me: My Z axis was crooked, the right side, because the frame screws had somehow come loose and were crooked... (from the small frame)
New pictures?
Cheerio,
RE: First layer rippling/inconsistent Z height
grab a guide gauge... do a calibrate z axis... and measure left and right then you'll find the error... the right side never went up 100%... and then you have such an error on the right deeper than the left... it's now behind me after 4 hours of repairs... I'll take pictures later 🙂
RE: First layer rippling/inconsistent Z height
I cleaned my print bed and did some extra tests. But the phenomenon is still the same. The nozzle is to close to the print bed on the right side. When I printed the skirt the filament came barely out of the nozzle in the front right corner of the print bed.
Now go to step 4 on: https://help.prusa3d.com/guide/8-preflight-check_464309#464453
and perform the self tests from there onward.
Cheerio,
RE: First layer rippling/inconsistent Z height
Did all the steps mentioned in the guide. Had some good layers, but now it's back. Very rough surface on the right side of the bed. Looks like the filament gets squeezed out because the nozzle is too close on the right side of the bed. I consider now to contact Prusa directly.
OK, but I would first try a drastic print sheet clean. Rub neat washing up detergent (Dawn/Fairy) into the print sheet concentrating on the areas where adhesion is poor, wait five minutes and then rinse clean with very *HOT* water. Handle by the edges only.
Cheerio,
RE:
Noticed some play in the right Z axis. Could this be my problem?
RE: First layer rippling/inconsistent Z height
...and what came of it?
RE: First layer rippling/inconsistent Z height
What was the fix? I'm seemingly having the same issue.
RE: First layer rippling/inconsistent Z height
I'm having a very similar issue with the first layer on my new Mk4. I have re-run all tests/calibrations and they all pass. I have washed my smooth sheet in dish soap and water and also used alcohol, yet I still get these grainy and ripple marks on parts of the first layer instead of it being entirely smooth. I'm printing Hatchbox PLA with first layer temp at 230C and other at 220C. Bed temp is 60C. Any thoughts or suggestions would be greatly appreciated. Thank you.
RE: First layer rippling/inconsistent Z height
My MK4 does the exact same thing, seems like the auto calibration of the first layer is slightly off. I fixed it by going into PrusaSlicer, into Printer Settings and changed the Z offset by 0.05.
