First layer of some objects *sometimes* gets 'engraved' into the smooth PEI Sheet (PLA)
My MK4 (and MK3.9) do print perfectly most of the time. When using the satin sheet for PETG there are maybe some failed prints here and there, but that is nothing special. The problem occurs when I switch the plate to the smooth PEI sheet for printing PLA: Sometimes the first layer of some objects on the build plate get engraved permanently into the build plate - I even had one case where only the first layer of the (organic) support left the imprint onto the sheet.
I have absolutely zero Idea what is causing this issue - I can print the same gcode 3 times in a row and have no issue - and on the 4th it happen or it can happen twice in a row...
- For PLA I clean the build plate with 99,9% IPA
- I use a brass brush to remove filament from the nozzle
- I slice with Prusa Slicer (stock profiles only with infill to gyroid and when printing supports organic)
- I normally use OctoPrint to print (prusa link is sadly not even remotely close) - but I am pretty sure it happend from USB to (I try to verifying that at the moment...)
- The loadcell test is successful, unloaded it reads around -20 with pressure around -500
- The hot end cooler is not screwed to tight
- The heat bed screws are tightened
- Newest stable Firmware 6.1.3
- I mostly use Prusament and Material4Print Filament
With support I just loop around the same routes of re-screwing stuff and do test prints and calibrating the load cell - and as those all work and print well (duh...) it all ends in a dead end or octoprint gets blamed as printing from usb stick worked for this sole test print (...)
Maybe I just sit it out buy 2 new sheets and wait till the core one conversion kit gets available but at least for my mk3.9 that option is not available...