Question Cura 4.9.1 seemingly random travel immediately after printing skirt

[brisance 0]

After printing the skirt, Cura 4.9.1 seems to make a random travel move instead of immediately putting down the first layer of the print.

 

Please take a look at this video. https://youtu.be/4aCgs_Ks3OI

 

Running on an Ender 3 v2 with custom firmware.

[fvrmr 73]

Hi @brisance can you also share a project file (file - save project) where this is happening?

[brisance 0]

Sorry for the late reply. Here is the file.

Clipasachet_v6_80mm.3mf

[GregValiant 1,344]

This is one of those shapes you need to play with.  Models that have hairpin / horseshoe shapes can be tough for combing as the nozzle runs all over the place, traveling up one leg and then down the other to avoid crossing the narrow gap.  This is especially true if it is "filling gaps between walls" at the end of each leg.

You have combing set to "not in skin" and Cura knows there will be a skin there on the build plate in the future so it generates combing moves to avoid that area.  If you move the Z seam to the hairpin turn (left in the 3mf) and change combing to "all" you won't get near the amount of travel.

On larger models, those long travel moves can give the nozzle time to ooze and when retraction starts again it can take a few millimeters to get going.  As the layers build up, that initial under-extrusion at the same position on each layer can turn into a very noticeable flaw in the finish.  I usually turn combing off on those types of models as it can cause more problems than it's worth.