Multiple retracts chewing through the filament?

[KevinMakes 22]

Has anyone else had an issue with printing parts with tons of retractions chewing through the filament and causing filament slippage? Solutions?

[Labern 774]

If the retract speed is to high it can lead to chewing through.

You could adjust the minimum travel before retract to help reduce them a bit.

Check the spring tension isn't to loose.

[KevinMakes 22]

Checked spring tension already its on the highest setting, the minimum travel for retract is kinda unhelpful. and the retracts are important because I'm using dual extrusion.

[yellowshark 153]

Almost without exception it is caused by your drive wheel being too tight on the filament. If you can manually feed filament through, eg using Repetier Host, then feed 40/50 mm through and pull the filament. Does the side pulled by the teeth feel almost smooth? If so you really should be Ok. If it feels any rougher that is your problem.

If you cannot manually feed then just print a square with retraction off and then pull the filament.

[KevinMakes 22]

Almost without exception it is caused by your drive wheel being too tight on the filament. If you can manually feed filament through, eg using Repetier Host, then feed 40/50 mm through and pull the filament. Does the side pulled by the teeth feel almost smooth? If so you really should be Ok. If it feels any rougher that is your problem.

If you cannot manually feed then just print a square with retraction off and then pull the filament.

 

when pulling the filament back out there is the grooves from the knurled piece that cause a little feedback but otherwise it is smooth.

[yellowshark 153]

Hmn, I would offer to try printing your model but my 2nd extruder needs a new heating element to be fitted and that is not going to happen in the next week or so. I don't know how big the model is but it might be worth scaling it up so that more material flows before a retraction. I know that is not solving your problem but it might give some indication of what is going on. Can we assume this is not a problem you normally experience?

[gr5 2,168]

I have a few printers - my oldest can do seemingly infinite (literally kilometers) of retractions with no problem. My newer printers can't. I solved the issue by increasing the parameter in Cura 15.04: "minimal extrusion before retractiong" from .02 to .45. I picked .45 because my retraction distance is 4.5mm so with .45 you can't have the same piece of filament go through the feeder more than 10 times (4.5/.45) whereas with .02 it can be 225 times! Having the same piece of filament go through 225 times is just too much.

I was worried I would get tons of stringing but it wasn't a problem - only about 20% of the retractions were discarded (on layers that were particularly bad) and the quality seemed the same.

[yellowshark 153]

Thanks for that George, a useful bit of info.

[ultiarjan 1,223]

And fyi, this is how to do it in new cura beta (15.09.82)