RE:
I updated firmware to 4.7.0 on 27 June and the Y axis homing failure issue is worse than ever. My MK4 was factory assembled and is 100% stock, no modifications.
The failure to home on the Y axis resulting in microcontroller reboot occurs on about half of the print jobs. There are no obstructions anywhere to be found and the belt tension adjustment did not improve the situation. I'm wondering the following:
- Would it be of any value to contact Prusa Support? They certainly must be aware of this issue by now. If Prusa Support is going to have me look for obstructions or adjust belts that is a complete waste of my time and theirs.
- I assume we must simply live with the issue until a firmware fix is released. What other options do we have, if any?
Thanks, Jake
RE: Y Axis now bashing repeatedly during homing
Very likely a bad motor, the resonance of it could be throwing homing off more than it should. The occurrences of failures went down drastically when I replaced the x axis motor, and did some tensioning afterwards when CS mentioned that it's VERY sensitive to things like belt tension and alignment.
I still think the firmware needs to be far less sensitive though, as it still sometimes takes longer than normal to home. It was never something I worried about when I had my MK3s+.
RE: Y Axis now bashing repeatedly during homing
Funny enough, I don’t have the Y bashing anymore, but 4.7.0 introduced X homing error (not as bad as the Y was) and a weird resonance I don’t have with any other fw. Going back to any other fw, no resonance and no homing errors.
i swear I don’t understand what is going on.
RE: Y Axis now bashing repeatedly during homing
What version firmware are you going back to? I'd like to try it too.
Funny enough, I don’t have the Y bashing anymore, but 4.7.0 introduced X homing error (not as bad as the Y was) and a weird resonance I don’t have with any other fw. Going back to any other fw, no resonance and no homing errors.
i swear I don’t understand what is going on.
RE: Y Axis now bashing repeatedly during homing
5.0 alpha2. I’m usually in input shaper fw, but these days I’m experimenting because I’m having issues with PETG (and not only me)
RE: Y Axis now bashing repeatedly during homing
For me it was the y-axis belt tension.
I checked the tension on the x-axis belt too, and thought it was too loose so I tightened it. Then I suddenly had the x-axis homing error. So I loosened the belt a bit and it worked again without the error. That made me redo the y-axis belt tension and it was too loose at first. So I tightened it, which made the homing error worse, and then I loosened it a bit and now it worked with just 2 trys on each axis. So I'm not 100% sure if it is fully fixed, but evening just homing works now without issue...Hope that it's fixed. I think what @shledge mentioned that the homing is VERY sensitive to the correct belt tension is correct. I think you have to find just the right sweet spot for it to work correctly. Still I think the firmware needs to be adjusted to make less of a hassle. Maybe if it helps someone: I found the homing makes a specific sound when the tension is right/the error doesn't happen. It's not as violent as when it starts bashing the different axis. It sounds a bit more dull. Also, if you are having difficulties finding out of the tension is right, I found that just putting a bit of pressure (and varying the pressure a bit) on the y-axis belt during homing I could make the error just occur. I also used the sound the bashing makes to see if it would work. Worked pretty well! If anyone has questions let me know and I will try to explain it better.
RE:
I tried downgrading from 4.7.0 and the microcontroller would not boot any of the earlier versions. It was stuck in a startup loop. Fortunately it is booting and function again after re-installing 4.7.0.
I've tried the belt tensioning and Y axis troubleshooting / resolution procedures documented in the links below. Nothing has resolved the issue. I'm confident it's a firmware issue. Does anyone know if Prusa Support is aware of the issue?
https://help.prusa3d.com/article/homing-error-y-13305-mk4_413188
https://help.prusa3d.com/article/adjusting-belt-tension-mk3-mk3s-mk3s-mk4_112380
RE:
I have contacted support multiple times about it, which is how I found out the tensioning etc. needs to be VERY exact. Also, the replacement motor also helps a lot.
So yes, it is mostly a firmware issue, but a noisy/faulty motor will make it worse.
RE:
For anyone who is registered at GitHub it might help if you posted a comment on this firmware bug thread. Doing so may bring more attention to the issue and make a resolution a priority:
https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/3116
RE: Y Axis now bashing repeatedly during homing
For what is worth, I’m quite positive it’s merely a fw issue at this point. In the last week or so I jumped between alpha2, 4.6.4 and 4.7.0 without encountering the problem anymore (2 - occasionally 4 bumps). Just installed alpha3 and here we are again with Y bashing and crashing 😂
RE: Y Axis now bashing repeatedly during homing
I also had the pleasure today that the y axis was just bashing... mine.the bearing housing on the left at the front came loose and the bearing moved to the front.. I was looking for a long time 🙂 but then I saw it. the bearing was not in its position... have a look at yours too it has to be in the bay and tight...
RE: Y Axis now bashing repeatedly during homing
I haven't had any failures since, so I think it somehow sorted itself out. Also can now definitely confirm that new motor and 4.7.0 seems to help a bit.
Even when using 5.0 alpha 3, I haven't had any issues.
RE: Y Axis now bashing repeatedly during homing
I've been running Firmware 5.0.0 Alpha4 since it was released and the repeated Y axis home bashing has ceased. Not certain if there was a firmware change, but after a dozen or so jobs my print bed only makes 2 "taps" on the Y axis during startup homing.
If the problem reoccurs I'll post again.
RE: Y Axis now bashing repeatedly during homing
The Y axis bashing and erroring out has returned and even worse than before. Three failures and reboots in a row this morning.
Obviously the firmware did not correct the issue.
I've been running Firmware 5.0.0 Alpha4 since it was released and the repeated Y axis home bashing has ceased. Not certain if there was a firmware change, but after a dozen or so jobs my print bed only makes 2 "taps" on the Y axis during startup homing.
If the problem reoccurs I'll post again.
RE: Y Axis now bashing repeatedly during homing
My MK4 has been repeatedly "bashing" in both y and x axis. It happened with 5.0.0 alpha 2, and today with alpha 4. Tech support was not aware of the issue.
RE: Y Axis now bashing repeatedly during homing
I have the feeling that the support often has no idea themselves and dices out the answers. Since really often the most senseless things come around, which you should check etc.. Next they tell you to knock against the motherboard case or something. Don't get me wrong but for me this is just not good support. At Prusa, it seems that mass trumps class.
RE: Y Axis now bashing repeatedly during homing
Don't get me wrong but for me this is just not good support. At Prusa, it seems that mass trumps class.
I understand, though I have to say Prusa is still better than most companies in this regard. I have had mostly good experiences with their support. But if every one of their reps doesn't know about this particular issue, they certainly should -- I am pretty sure it has been reported to support multiple times by multiple owners. For a rep to say they are "not aware of it" seems like a real failure of whatever internal knowledge sharing base they use. Alternately, I suppose it could have been a new person not yet fully versed on interrogating their system.
But as far as this issue itself goes... I am still seeing it too, but way less frequently and less severe. Maybe once every 5-6 prints, and when it does occur, it usually resolves itself with 4 "bumps" instead of the 12+ I had experienced originally. And still mostly Y axis for me; very rare on X.
I have no clue why it has improved; it *seems* like *perhaps* the improvement was coincident with loading firmware 4.7.1, but the problem "comes and goes" so intermittently that I can't really associate it with any specific change or condition. It could also be something about belt tension changing over time, or ambient temperature, or the phase of the moon as far as I can tell. It just seems to "come and go" with no pattern that I can discern.
RE: Y Axis now bashing repeatedly during homing
I agree with you ScottW. Despite the issues, my prints are flawless. Support is consistently good compared with support from my previous Chinese Printer manufacturer that rhymes with reality! Everything they sent me was incorrect, even wiring diagrams!
Checked belts using the app and all was fine.
So I ran Firmware 5 Alpha1 just to put the printer to the test and the results were great. My theory was that at those speeds, anything dodgy would show some sort of artefact. I then went back to 4.7.1 which would not proceed past the Homing y axis failure. Loaded 4.7 and it still fails, but continues to print perfectly. I use the system self tests on all versions and all pass in the x, y and z checks.
I am currently still on 4.7 as I am waiting for an official release of 5.
RE: Y Axis now bashing repeatedly during homing
So, a quick update. I used the Belt Tensioning app and on the Y belts, it randomly said it was fine, then too tight, alternating between the 2. So yesterday i adjusted the belt tightness, decreasing the tension by rotating half a turn. Today, using FW 4.7, i started a print and for the first time, no error on the Y homing!
More testing to come!
RE:
The belt tensioning app is bullshit in my eyes. You can use 5 different smartphones and become 5 different results. In my case I use the belt tensioner tool from printables. I used the app before and my belt was tighter but it makes no difference. No matter how tight or loose the belt is, it makes no difference. The belt tension is only just a standard answer that Prusa support has to suggest to customers. For me, it also sometimes runs for a long time without the problem and then every now and then it occurs sporadically. Just like the extruder on X-Axis when Homing he crashs against something invisible if moves to the left and then to the end of the X-axis. I don't worry about it anymore as long as everything else works.
So, a quick update. I used the Belt Tensioning app and on the Y belts, it randomly said it was fine, then too tight, alternating between the 2. So yesterday i adjusted the belt tightness, decreasing the tension by rotating half a turn. Today, using FW 4.7, i started a print and for the first time, no error on the Y homing!
More testing to come!