How to perfect combing to avoid stringing

[qt1 1]

Hello !

 

I'm fighting with "combing" and "avoid printed part when travelling" to prevent stringing possibilities.

Is there a way to avoid the travel path like the ones in the left of the attached picture ?

 

Thanks a lot !

MtAiguillle Cura.3mf

[gr5 2,071]

I'm surprised that it's not combing.  Well the upper left corner it thinks it has to retract as it's a separate island.  Did you try setting "travel avoid distance" to zero?  I'm wondering if the travel avoid thing makes it want to go outside your printing area possibly and then that triggers something that decides to instead avoid combing?  I'm thinking this is a stupid idea on my part.  But worth trying as you can see the result instantly in PREVIEW.

 

I know you have this mental concept that outside the square is a good place to do combing but I don't think cura is that smart to realize it is on the edge of your part - I mean there is a printed wall all around that upper triangle and it has to cross that wall *somewhere* to get to the lower area and continue printing.

 

8mm is a long way to retract.  Did you try shorter distance?  You don't want it to retract so much that it lets any air into the nozzle.  If you have a bowden printer you want the filament to retract just enough to stop pushing up against the top curve of the bowden arch.  The longer the distance, the longer it takes and that gives it time to leak.

 

Also crank up your travel speed.  Many printers can do 300mm/sec.  Typically the printer firmware will limit the speed so you can just set it to 1000mm/sec in Cura and the printer is supposed to keep the speed to something it is capable of.

 

If you print slower and with cooler temperatures or with a smaller nozzle it will leak less as well.

[qt1 1]

Thanks for your tips !

Yes indeed I know 8mm is a big value that will fail at a retractation test (4 is my sweet spot) off course but I wanted to give it a try for this kind of print for the next test...

I did try just now to put travel distance to 0 but nothing changed.

I will crank up travel speed it's a good idea thanks and I totally get what you mean by "not smart enough", this is indeed true that sometimes humans are hoping to much from machines !

But I would appreciate to have a kind of "avoid travelling over previously printed part" option someday 😉 (or travelling over skirt).

 

Best