Optimizing Filament Change Routine for MINI
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Optimizing Filament Change Routine for MINI  

New Member
Optimizing Filament Change Routine for MINI

Hello everyone,


while printing multi color prints where i use different filament colors at various heights on the PRUSA MINI i found the following issue with the standard slicer profiles:


The filament is changed at a certain height. I feed the new filament and once it extrudes  in the correct color i confirm the change on the printer. Now however some filament is already drooping out of the nozzle. Then the printhead returns to the print. The first 30-40 mm almost no filament is extruded. This causes some issues when printing very fine structures like Text, in a different filament on top of a print.


My suggestion is the following: After confirming the filament change, the extruder could extrude some more and then retract. Then when it reaches the print it undoes the retraction and now the nozzle should be filled.

I think my mk3 was doing something similar where after confirming the filament change it extrudes a little bit more filament and then moves the extruder to the print on the bed.


My current workaround is to first add a small cylinder in the slicer. It seems by adding the cylinder first, it gets printed first. Therefore the underextruded lines end up in the cylinder  and not in my actual print.

What is your opinion on this?


Best regards


Posted : 11/06/2020 9:54 am
Active Member
RE: Optimizing Filament Change Routine for MINI

Same issue here. I'm affraid it is not solvable in slicer, as it only writes M600 command and the retraction is done by printer firmware.

As I needed to swap colors after embosed image, I changed infill_first to true (In Infill -> Advanced. You have to switch to expert view) so the missed part will be hidden in infill. But that won't help you with narow raised text. In that case, I just use more layers and hope that it will self heal on next layer.

Posted : 18/12/2020 10:52 am
New Member
RE: Optimizing Filament Change Routine for MINI

I am having the same issue here - would really love a fix or tips on how to workaround.

I have found that having a skirt of at least two loops for the entire height of your model is a "solution" because it does the color change halfway through printing the skirt. Therefore the underextrusion or blobs (whatever the case may be) end up on your throwaway skirt instead of your print. 

Posted : 20/07/2021 12:02 pm