Corner banging question
I have been suffering from lengthy corner-banging issues like many I've seen here.
I've gone through several rounds of trying to bend the gantry back into square and subsequent belt tightening games. I don't think it has helped a lot. Hard to say.
I'm wondering something: at this stage, when I fully loosen the belt to attempt squaring the gantry yet again, I have play in "both" sides. While I see posts suggesting that if one side has play then we need to bend things so that both sides sit flush, neither of my sides sit flush. Have I bent them too far? Is something else off? Is this expected? FWIW, this is a factory-assembled printer.
RE:
The play on both sides is normal. When the belts are slack, they "bounce back" and cause the play.
What's important: if you tune both belts to the same frequency and then move the print head to the front, while in the middle of the linear rail, the two end-stops should touch at the same time. If you need more than 2-3 Hz difference to achieve this, loosen the belts again and bend the brackets with the wrench-trick.
However, even if you get it close to perfection, the print head might still bang a lot. I re-tuned my belts last night and it kept banging for a minute...
What to do: simply play around with the tuning of the right tensioner. In my experience, the right side should touch the end-stop a tiny bit before the left side, but still basically at the same time.
The important test is the "Auto Home", while the printer is cold. That way, the heater is not interfering with the loadcell. Just test it via the display - > Control -> auto home.
It's a quick test. Auto Home, adjust tension in any direction, Auto Home, adjust again. At some tuning, it will be consistently short.
If that works flawlessly (2x side hit, 2x front hit, 3x side-front double hit), you can start printing again. If it then bangs longer, search for Custom Start G-Code on the forum and disable the hotend heating for homing (and nozzle cleaning).
Written on my phone, hope it helps!
RE: Corner banging question
This gives me a process to try, thank you!
On a side note: is there any chance that a future firmware update might help with this?
RE:
I didn't look into the firmware to check what's happening, but I think it could be solved, yes.
The end-stops need to be hit quite fast, to trigger the stalling of the motors, but I think the loadcell signals can be filtered better (which sits in the frame, that bangs against the side stop).
The other issues with the loadcell could be solved, if the hotend heater gets disabled, when a loadcell signal is estimated to happen. Like banging once, noticing a spike in the loadcell signal, disabling heating, banging again and getting a clean signal.
Same for nozzle touches (Z-Homing, Nozzle cleaning, MBL probing). Code a little algorithm, that disables the heating for a short moment, done.