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.

It seems from reddit posts most have printed front and back as 2 separate stls and then glued the 2 pieces together.

We're interested in printing many as free giveaways and gluing them together could be time consuming on a work project that has a deadline of 2 days ago. Plus, we worry re: glue and the public not always being the best bet.

Has anyone printed a 2 sided coin by standing the coin up vertical on the bed to print on both sides?

Appreciate you sharing your experiences and what you've learned from them.

Thank you!