Printing PETG is really hard to do without some nozzle buildup. On longer prints, I’ve had to resort to pausing a print to reach in with tweezers to pull a blob from the nozzle. It’s not a huge amount of buildup, but if it’s not cleared off, on a long print, it’ll eventually get deposited someplace that could be visible.
On multi color prints, the printhead goes to the back/center of the build chamber and pauses. It’s almost where it needs to be to wipe, anyway. It would be great if instead of just sitting there, it wiped the old nozzle prior to swapping to a new nozzle. Would cost next to nothing in swap-time.
A few times, I’ve actually had to pause the print so I could reach in with some long tweezers and yank a dingle berry off the nozzle. So, I actually amend my suggestion to include a full wipe whenever you hit Pause. Keep the nozzle hot, do a full wipe when restarted.
The prime tower doesn’t do anything to specifically remove stray filament from the nozzle. It might grab a string or a blob and pull it off, but that’s by no means a sure bet. Where a wipe at the back of the chamber’s nozzle wiper thingy, most definitely would be (a sure bet to remove stray filament).
Is it possible to please share a few .3mf files where this issue can be reproduced?
It would also help to let us know what kind o filament was used, if it was dried or not and other important details.
Pictures of the buildup can also help us.
The team is working on such a feature, but it would be useful to have an issue that can be reproduced so that we offer a good solution.
It should be pretty easy to reproduce. I’m using MatterHacker PETG with the default generic PETG profile, except I’ve increased extrusion temp to 265 because the MatterHacker doesn’t flow well enough at 255 if I run Sport. Not object dependent. Just has to be reasonably large, and there has to be more than one so there are travel moves on each layer.
It’s not a huge problem. More an annoyance. Not a fault of the printer. Just a problem for PETG if it’s not tuned really well (I’m using auto cals). It strings. Some gets on the nozzle.
I’m glad to hear the development team is working on a wipe feature. I can’t imagine it’s all that complicated to implement, so hopefully we’ll see it soon. That’s all it takes to make me happy.
I am using all nozles , LEFT and all 4(AMS) From the RIGHT Vortex ,
i believe that the problem seems to happen when the LEFT nozzle enters the game by extruding in the tower , this is starting to making it harse and the tower becomes weak and colappse when violently the right extruder clear nozzle against the string mess , i hope it make sense , to make a quick and dirty solution is to add more brim into the tower
Filament profile issue. Use Bambulab PETG profile instead. Must be some retraction difference between generic and bambu filaments. But I’m using all bambu profiles so I’m having no issues at all now.
That’s a filament drying issue IMO. The long scrawny noodles of filament that get stuck to the prime tower are what’s oozing out of the nozzle on its own during the filament swap. Moisture is what causes that oozing.
The issue I’m talking about is nowhere near that level of severity. I get a tiny amount of buildup, the prints otherwise come out fine (unless the buildup gets dropped someplace visible during the print).
Couple things to do in the slicer that will help keep the supports or prime tower from getting knocked over. EDIT: OK, Couple two, tree
First go into others and uncheck the Reduce infill retraction, its at the bottom. This will set it so the bed drops a bit when the head moves from structure to support. It is on by default to reduce how much the bed (Z Axis) moves during the print to reduce slicer and print times. I found the time difference basically unnoticeable.
Second, under the filament settings are options to wipe while retracting and wipe distance. It is disabled by default, but it you have certain filaments that you need nozzle tip cleaning, you can check the box and save it as a special profile. Just remember to switch to that profile after a sync is done because its through Slicer not the printer.
Third, to help keep the prime tower planted, you can increase the number of brims to hold it down, Default is 3, I use 5, have not had a tower fall over since.
Mine already does this, it seems. I’m not entirely sure if the length of the pause matters, or some other factor(s)?
But I’ve definitely seen it wipe, after reheating the nozzle and before printing. After a “longer” pause it also extrudes some filament first before the wipe. (I’m talking about the silicone wiper pad at the waste chute, not the abrasive nozzle cleaner area next to the plate.)
Unfortunately a wipe still doesn’t seem to be 100% reliable for removing buildup either… Plus it still has to be initiated manually in this case. The prime tower idea may help. Also we could probably insert some custom g-code to do wipes between layers (for example), carefully of course. Smooth timelapse does move the head to the chute but I don’t think it wipes afterwards (from what I can tell looking at the g-code).
Yeah. I agree. My original understanding was flawed. I agree the wipe is not as effective as it could be, too.
With PETG, I’ve found the wipe is just as likely to ball up any leftover purge filament as it is likely to scrape it off. I have had to pause again and reach in with a pair of long tweezers to yank a blob off that was caused by the wipe.
Really hope this feature gets added in some way. It would be nice if I could manipulate it via slicer settings or from the printer. Perhaps a “enable wipe“ boolean with a wipe frequency color change setting that would allow me to say “if 100 color swaps have elapsed during the print, wipe the unwiped nozzles on swap“. Not all at once, but just when it finally gets to that color in the rotation, then proceed with the frequency counter again. Another solution would be to have an elapsed time frequency, wipe the nozzles, etc. I too, have had to pause the print to grab a tiny chunk of petg stuck to the rubber sleeve of the vortek induction nozzle. Sometimes the fragments are stubborn and won’t come off on the tower but would come off with a strong, but quick wipe.
