Factory built MK4, first layer failures
I have firmware 5.1.2+13478 with boot loader version 2.3.4, Prusaslicer version 2.7.1+MacOS-x64. All initial tests and calibrations ran and passed with no difficulties. The Prusa key fob printed correctly in the center of the bed using Prusa PLA.
However when I attempt to print a large item that I've re-sliced for the MK4 using input shaping and structural, the printer is not laying down a perfect first layer. These print correctly on my Mini+ (sliced for input shaping and structural for the Mini+). I've verified that the loadcell is plugged in correctly and have tried recalibrating it. When I look at sensors/loadcell on the display i note that the loadcell values continue to change, but I don't know if this is a problem.
For the last photo with the black prusa filament i sliced the file with load shaping off and it is printing much better, but there is still an issue that looks like uneven heating on the bed in much the same place that it is seen with the gray filament.
I'm not sure where to start on solving this. Seems like the printer might have 2 separate problems. Any suggestions?
Thanks!
Ken
RE: Factory built MK4, first layer failures
After several days, Prusa has still not replied to my support email.
By not using input shaping, by reseating the nozzle several times, by doing the Z axis calibration again, by making sure that the loadcell is plugged in to the loverboard solidly, i get a much better first layer but one that is not as good as my Mini+. This is disappointing to say the least.
RE: Factory built MK4, first layer failures
Looks like a low spot in your bed or sheet. Try flipping the sheet over. I have some PEI sheets that have low spots like that and I don't use that side. I wrote with sharpie on them not to use that side.
Fwiw the first layers on my MK4 are perfect. I've had it for about 9 months.
One thing to keep in mind is that the nozzle needs to be clean before it probes the bed. This is particularly important if your filament is oozing after the print. That oozed filament will mess up the calibration. I don't think that's your issue here, but keep it in mind.
RISPONDI: Factory built MK4, first layer failures
I think that the calibration serves precisely to overcome imperfections in the bed and any problems with leveling the axes. However, I believe there is some problem with the load cells and the algorithm that controls the leveling. It's not the first time I've read about problems on some MK4s, even on the factory-ready ones.
RE: Factory built MK4, first layer failures
Thanks guys... I may have another problem: I tried printing a temperature tower, but I never see the temp as reported on the printer display ever change. its sits at 220 and never changes even as the MK4 prints different levels of the tower... I would expect the display to show the correct temp, so this means that the temperature is never changing?
Ken
RE:
Common problem,
You need to program temperature changes at different heights.
if you get an STL, it only describes the model geometry, look for a .3mf project file, or pre sliced, gcode and you stand a chance of the temperature functionality working
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RISPONDI: Factory built MK4, first layer failures
What's the point of changing the temperature at different heights if it's only printing the first layer? If you intend to try at different temperatures this is the first thing I did: PETG at 230 240 250 260 what you see in my photos is the best result with PETG 240 °C at other temperatures the result is not even photographable.
RE: Factory built MK4, first layer failures
Yes, my face is red. I was in a hurry and it slipped my mind that my sliced gcode didn't have temps embedded.... I was wanting to see if there was a problem with my filament vs temp--it was about the last thing I could think of trying.
I did work with the folks on Prusa chat and that got me going: wash the plate with soapy warm water, dry with paper towels, and then preheat it to 100C for about 10 minutes. Try a print and increase the temp 5C at a time and see if it gets better... I did this and though it did look better at the same temps I'd been using, raising the temp on the Hatch filament made it worse, so I went down to 30C bed temp and 215C for the filament. This made a big improvement in the first layers, but the filament needed more heat on the upper layers so I dialed it back up some. Looks pretty good. I need to do this with the Prusa PLA and see if I can find a sweet spot for it, too.
Obviously, I'm no expert at this though I've had very good luck with the stock settings for filament including the Hatchworks with my Mini+. I expected the MK4 to work the same--lesson learned. Thanks everyone for your help and to Joan for reminding me that the gcode needs the temp changes embedded for a test tower. oops.
Ken
RE: Factory built MK4, first layer failures
Same thing is happening to me, and just tried the washing and preheating bed to 100c for 10min. So far that's made my prints even worse.
It's like each line of filament is splitting.
Still no resolution