Lumps in MMU3 Unit2 print
My Mk4S (my second i3 in six years) has printed hundreds of parts without a problem; it's fully dialled in and working fine.
But trying to print the MMU3 Unit2 bgcode (before the kit arrives) has failed four times now, twice due to layer shift and twice because I detected big lumps of plastic in the middle of the print around layer 2 that the nozzle was bumping into - and I would presume caused the layer shifts. I'm using PETG on the textured sheet.
What could be causing this and how to stop it? Anyone else experienced this?
RE: Lumps in MMU3 Unit2 print
That´s interesting, because I have had a similar issue.
I printed a lot of things and never had a layer shift, but with these parts it happened to me.
First I thought, the filament was bad and made some bloops, so I chose another one and reprinted everything It was much better, no layer shift, but the surface was not really good. I think these part is useable, so I did not reprint it again.
RE: Lumps in MMU3 Unit2 print
I think I may have got to the bottom of it: the downloaded binary gcode files set the printer to use its Speed profile. Over-fast printing is notorious potential cause of just the problems I've encountered.
So I downloaded the STLs and resliced using the Structural profile. Yes it's nominally slower - but not once you factor in the time lost chucking away failed prints. And now I've run all the failed prints again - the biggest one was Unit 2 which has comfortably passed the point where it failed before, several times. It will take once finished about nine hours compared to seven with the Speed profile but it is after all a structural part.
Baking in the Speed profile seems to me like a surprisingly poor decision by Prusa.