I recently bought the TPU Assist Module for my P2S
I assembled it fine but it won’t calibrate
I hold down the feed and unfeed buttons for ~10s, the LED flashes, I feed in a hard filament (tried PLA and PETG), it feeds in fine all the way to the print head then sits making a grinding noise and never stops/completes calibration.
I’ve raised a ticket with Bambu and am now waiting for a response
There’s a reddit thread (TPU assist wont calibrate? : r/BambuLab) that seems to suggest it’s a hardware fault and only fixed by Bambu sending a replacement out
I’ve opened the thing up a dozen times and checked every cable, no pinching, all seated correctly.
The buttons work fine to load/unload filament but it will not calibrate no matter how many times I’ve tried - I also tried long & short ptfe tubes, tubes held perfectly straight, etc….
I had similar problems. There are two things that I think have been found to contribute. There needs to be some flex or bend of the PTFE tube path when the filament bottoms out. Personally had to go through three different filament types and brands before it actually calibrated. How this helps.
Just as a test, make sure your PTFE tubes are cut cleanly and are fully inserted into both the assist and the extruder.
Start a calibration and when it’s just started feeding, push down slightly on the PTFE fitting on the module that goes to the printer. You should feel a “click” and that should make the feed stop.
This confirms that the pressure switch is working properly (or not), because what you’re saying sounds to me like it’s not being triggered.
I decided to swap individual components just to fulfill my need to understand what wasn’t working
The sensor board on the side of the motor module was faulty. Swapped that for the new one and it calibrated first time
Hopefully if others have the same issue, as on the reddit thread, this will help - obviously some of the boards being sent out aren’t functioning. But many thanks to Bambu as it took a while but a full replacement order was sent out
I had a simular issue with the calibration as well, and after some exchange Bambu sent me a new module, which had exactly the same issue.
It took quite some time before I figured out the you have to press the load and unload buttons much longer than I did.. It just did not go into calibration mode, but did start to feed the PLA in the unit until it jammed and started whining.
It wasn’t until I realized that the flashing should change from a 50% interval to a 10% interval to really go into calibration mode.
Perhaps I’m the only one, but I think the two different types of flashing without this specificallly being mentioning in the wiki is quite confusing.
