"Hardware retraction" causing pauses
Hi
I wanted to cure the "bits" of print material that seem to litter a lot of my prints (not just stringing, but bits of rubbish where the filament curls up the nozzle, accumulates and then periodically dumps itself on the print) and seem to have made my issue worse by setting hardware retraction on in the prusa slicer. It says it works with marlin, which is what i have selected.
However every time it retracts, there is a noticeable pause, which is long enough for the nozzle to start to melt the material its sitting on and again, start pulling up little bits of filament. I would like to fix the "littering" primarily, the issue with hardware retraction is no biggie as I can switch to using the retraction settings.
Attempted fixes:
2. Tried increasing temp to 245 (made worse), and decreasing temp to 235 (stayed the same).
3. Bed calibration was performed using the "test square" gcode from this forum and it was set just at the point where the lines merged smoothly.
4. Its a new nozzle and heatbreak, all parts are tight and there is no leakage. This seems to be more the print material "creeping up" the nozzle, cooking and then coming off.
One other thought - I recently retightened all the extruder parts and recalibrated, and my functional live z adjust is now higher than it used to be, ~300um rather than ~500um. Is it possible the nozzle it sitting a little too low, and a PINDA adjust might help?
I am printing with Prusa PETG at 230-240 and bed at around 80-90. Do I have some hours of experimenting with retraction settings ahead of me?
EDIT: Here is a picture. Note the piece at the bottom left, which required removing with a craft knife
Re: "Hardware retraction" causing pauses
It looks like the batch of Prusa PETG I bought is 1.78mm in diameter (used mitutoyo digital caliper in 5 spots) so that may be why I am getting so much debris. I have updated it in the slicer and am experimenting with turning 'flow' down during the print, any other suggestions?
Re: "Hardware retraction" causing pauses
Hello Ross!
I had a similar situation with stringing (that may get caught on the nozzle). Have you tried set the - 'Minimum travel after retraction' to a value that is less than the distance between the holes in the object? Then you may get rid of the stringing with a decent setting on the retraction (e.g 0.6 - 0.8 perhaps).
/Henrik
Re: "Hardware retraction" causing pauses
Hello Ross!
I had a similar situation with stringing (that may get caught on the nozzle). Have you tried set the - 'Minimum travel after retraction' to a value that is less than the distance between the holes in the object? Then you may get rid of the stringing with a decent setting on the retraction (e.g 0.6 - 0.8 perhaps).
/Henrik
Hi Henrik, I may have played around with that setting but dont remember specifically, so I will definitely give it a go when I am next printing 🙂 I had also wondered if I might be overextruding because I have a lot of "zits" in the side wall of the part. Do you happen to know if setting the correct measured diameter of the filament in Slicer autoadjusts the flow, or do you need to manually adjust flow rate too?
Looking forward to experimenting!
Thanks!
Re: "Hardware retraction" causing pauses
You should be fine with just setting the filament diameter in Slic3r - I think it will auto adjust to extrude more or less depending on that setting. Don't forget to set the filament diameter to a mean value of several measurements of the filament. You may get many values depending on where on the spool or where on the circumference the measurements are taken. I have seen oval diametres as well as a wide range of measurements not within the specified +- 0.05 mm diameter.
/Henrik
Re: "Hardware retraction" causing pauses
Why are you experimenting with the firmware retract?
Current Slic3r PE could be configured to use different speed for retract and deretract, therefore I don't see any benefit of using the firmware retraction.
Good luck with the PETG build-ups on the nozzle. Unfortunately this is one of the cons of the material. You may use the NGEN, which is a form of PET copolyester. It does not cause as much of the build-up issues.
https://ngen.colorfabb.com/