Filament grinding.
Hello!
I've run into a problem where the filament gets stuck for some reason, but the printing doesn't stop and the extruder starts grinding the filament.
I've already done this with two heads.
I'm definitely going to take one of them apart because it was so full of junk. I noticed it too late.I managed to stop the printing with the other one after a few empty layers.
It went further the second time than the first.
I print from a Sunlu S4 dryer. At first I thought that maybe the piping was too steep. But the second time it wasn't a problem. In principle.
The material is BambuLab PLA Silk. The last time I printed well with the BambuLab X1C. That was more than a year ago. I dried the material continuously in the S4 for 6 hours at night. The drying didn't stop even after the continuous cycle, until the desired humidity was reached inside the device.
I already turned off the drying when printing. Also, I didn't dry it before the second attempt and it printed further than the first. So I would rule out filament that is too wet.
For the filament, I used values from the default settings of BambuStudio, such as the extruder multiplier 0.98, print temperature 220 °C.The bed temperature remained 60 °C, the max volumetric speed 15 instead of 21.I also printed in 0.20mm Structural mode.It's the same model.
The filament could be pulled out with a filament unloader.
The picture of the filament is a piece taken out of the first extruder.
It's still in the second one, I took a picture of it at the extruder wheel, as it looks right now.
What could be the problem? Is XL allergic to BambuLab materials? I don't think I've printed BambuLab materials with it yet. I've printed a lot of Sunlu and Prusament. And a couple of other brands too. I have several rolls of BambuLab material because of the X1C, although I already loved Prusament, so I have more of it.
But for two or more colors like this, I can only reach for the brand that makes it.
What else I can do is try to print the model with another material. I have one loaded, and I printed successfully with it yesterday. If that also gets stuck, then the problem is probably with the model.
Although I recently had a model that I printed 4 copies of one by one and the printing stopped at the same point in all 4 due to a filament jam. There really wasn't a problem. The filament came out smoothly and went back without cutting and the printing continued without any problems. It was Prusament material.
Now I don't even understand why it didn't stop. In the first case, I clearly heard the extruder clicking. I looked, but unfortunately I didn't notice that the material wasn't coming. I was clearly blind, I wasn't looking at it from the right angle.
It would be nice if someone could give me some tips and advice on how to print with Bambu materials. I don't want to throw them away, and I don't have anyone I can give them to. It would also be nice to print with this color combination, but that's not why I'm buying a Bambu printer.
PLA Silk.
Foaming and expanding filaments should be regarded as exotic and technically difficult, the 'silk' description is a cynical ploy by manufacturers to make them sound innocuous.
In this case you can't reasonably accuse Bambu of anti Prusa skulduggery as this will be a tricky print on any printer - of course they (only?) supply proformas for their own models...
Foaming filaments do have a use when light weight structures are required and in the case of some foaming TPE's where adaptable softness/resilience can be tailored to a task but IMO, using them for cosmetic effects is inviting trouble.
Print the filament slowly, allow time for the uneven pressures of expansion in the extruder to even out especially so if you are varying the temperature to change the density of different areas of the print. If possible, lay down the first layer in a compatible, non-expanding filament.
Prusa do supply a Generic PLA Silk preset suitable for XL - I would start from there and slow down if problems recur.
Always unload and run some vanilla PLA through the extruder between silk prints and expect to clean dust out of the extruder gears more frequently than usual.
Cheerio,
RE: Filament grinding.
Thank you for your willingness to help!
The printer has no problems with Sunlu Silk PLA+ materials and I have printed a lot of them.
I also don't think that Bambu would directly sabotage printing with the Prusa.
There are simply materials that some printers like less than others.
I will look into the Generic PLA Silk setting.
I would definitely note that I printed this material faster with the X1C without any problems than I did with the XL.
BS
RE: Filament grinding.
I took apart one of the extruders. What I found inside didn't look good. I cleaned it.
But based on this, I have to disassemble the other extruder as well.
And in the meantime, I figured out the problem.
There's a problem with the filament.
The cross-section is not circular.
So in some places it can reach 1.84 mm thick, while the flatter part can be 1.64 mm.
And 1.84 mm is already too much for the XL head. It starts to grind, and then when there are a lot of small particles, the filament gets stuck.
I measured the thickness of another BambuLab PLA Silk two-color filament and the same thing happened.
BS
This used to happen with cheap filaments but that much variation is unusual these days. If the thickness is consistent the value can be entered in the slicer with a good chance of success but not if the whole spool is inconsistent.
Cheerio,
RE: Filament grinding.
The value doesn't seem to be constant.
But that's not the biggest problem, because what the printer printed looks good.
The problem is that the filament doesn't really fit into the Prusa nozzle.
I think the heatbreak inlet is thicker in the X1C.
That's why I didn't have any problems with printing.
I got good quality there too, I had no complaints about it.
If only this 1 roll had been like this, then I would say I got a bad quality one.
But the other roll, which consists of other colors, is also like this.
I'll look for a single-color normal Bambu PLA and measure that too.
But maybe I sold those rolls together with the printer.
BS