First 10 Layers are loose
I have the MK3S+ with MMU2S and I am starting to try some single material prints to test everything out before I get into multi-materials.
Initial setup and prints was great, first few test objects were simple geometry, and printed very impressively with default settings. I had to dial the Z down to get better plate adhesion, but after that, it was fine.
Now the past several prints - with either PLA or ABS, all have the same issue: the support matrix is nice and tight, and then the first 10 or so layers of model geometry (adjacent to the support) are comprised of loose filament that is hardly bound together and the perimeter is smaller, like someone squeezed down the geometry 10%. After the layers build up, they are perfect, crisp geometry and the expected density and surface finish.
Could there be a calibration issue or something loose at the bottom of the z-axis? Something else? I've even tried running it a little slower like 80% to see if that would help, but it did the same thing, only 20% slower!
Photo for reference, the flip side is nice and solid and smooth.
RE: First 10 Layers are loose
Way too loose. Either a first layer issue or a temp/under-extrusion issue. PLA or ABS - what a strange combination. We don't get ABS printers often because it is somewhat advanced, requires an enclosure to print (fumes and tech level needed to understand ABS)
RE: First 10 Layers are loose
Dan, can you help clarify? The shrunken perimeter makes me think that there is something too tight or misaligned in the lower part of the Z...? If the feeder is too loose and under-extruding, why not in the remaining layers? Is there an adjustment I should consider with the MMU2 unit feeder? Simple printer file setup adjustment?
The ABS seemed to print just fine. I used to use a Stratasys machine at my old job, and I do recall the enclosure - but the build plate was not heated like the Prusa unit. So far I've been pretty impressed with the ABS prints I've done, which look dimensionally similar to the PLA prints.
RE: First 10 Layers are loose
I went ahead and re-ran the initial calibration steps for the printer, and made sure all the jack screws are clean. The problem of the shifty, loose first layers is mitigated. The next step will be playing with the settings for the layers adjacent to the support, shrinking down that gap and dialing, the bridging.
I also did another print of ABS, which printed impressively well. It had some flat planes so I printed without support. Seems fine for the time being.