With 2.5h left of a 16h print I got the error that the filament wouldn’t reach the toolhead. It came close, then it went back to the spool and it repeated itself a couple of times.
I tried a couple of things, but nothing seems to help. After a couple of tries the error now says instead theat there is a buffer error. I dont’t want to abort, but I might have to.
I recorded a video of what is going on but I can’t upload it. Took a picture instead. The highlighted part is as long as the filament goes. The filament motor keeps on going but the filament itself stops there.
I’ve yet to see a buffer error. Perhaps there is something in the buffer clogging it up. Maybe try removing the inlet tube from the buffer and see if filament can push through easily.
I think if you unplug any cables it will abort the print though.
I second removing that guide for the tubing. The filament has to make a hard 90 degree turn down to toolhead and I would not be at all surprised if the sharp tip of however many prints you have made has damaged the PTFE tubing and it is snagging in that bend.
Make parts like PTFE guides if and when they are needed. My P1S has no guide and I suspect many if not most other folks also don’t use a guide.
I bought a long piece of the Bambu Lab PTFE tubing purposefully to have very long radius curves from the toolhead to each AMS. Long curves apply less pressure per unit length of tubing than a short radius curve
From the tubing order page.
Overview
The function of PTFE Tube is to reduce resistance and guide filament. The tube’s inner diameter is 2.5mm, and its outer diameter is 4mm.
Please note that the PTFE tubes are consumables and are at risk of wear, as they may rub against the filament over time. We recommend that you check the PTFE tubes for wear during your maintenance of the machine.
If the tubes are worn and not replaced in time, this may lead to feeding failures, filament accumulation inside the AMS, etc.
A pair of diagonal cutters will remove those things from the PTFE without you having to disassemble anything. Destructive removal. Reprint new ones if you decide they were actually a help and not a hinderance.
I think BBL didn’t leave themselves enough margin with the bend of the PTFE tube where it meets the printhead. The filament will bind there, and bind more the sharper the bend. So things that make the PTFE tube bend even more than necessary, or that “constrain” the bend so it cannot flex might be less of a help than you might be hoping.
If you are bothered by the PTFE tube rubbing on the underside of the top of the printer enclosure, IMO a better option than that blue thing is to print a 1" riser to move the printer’s top up a bit.
It can’t possibly be straight, but you want the PTFE path to be as straight as it can be. The system is designed to give up pushing filament if the resistance is high enough. Bends add friction.
Another option to increase the radius of the toolhead bend, is to install a riser.
I designed an LED riser (there are a bunch already out there, I know but I didn’t like the options at the time), it gives my print area way more light and allows for larger bend radius.
I really do appreciate all your time trying to help solving my issue. I managed to remove the mod and tried again… without success. The problem still persists.
I am wondering if it could have something to do with something being in the way of the filament sensor?
Again, the filament stops before entering the toolhead but the AMS motor keeps on running for about 10 more seconds before retracting and doing the same thing three more times before finally giving up with the error message saying that the AMS motor is overloaded.
I recently replaced all PTFE tubes in both of my AMS and occationally the tubes leading from the AMS to the hub (because I use a lot of Polyterra and boy is that platic abbrasive). So, bad tubes is out of the question as well.
Back to the drawing board, I guess…
Where the filament exits the end of the PTFE tube, before it enters the top of the printhead, there is a small gap. If the end of the filament is bent right, it exits the PTFE tube but does not enter the top of the printhead opening. The AMS will bang the filament in to the printhead, retract, and try again. Like you describe.
You’ll have to pull it all the way out, but try cutting an inch off the end of the filament and see if it’ll load, then.
