New 3.0.10-RC1 firmware for Prusa i3 MK2  

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

hi christophe
can you reproduce this behaviour, or did it happen just once ?

Yes, just did it again and same kind of issue. This time Z didn't move but X and Y just start to slide for no reason when trying to move Z axis jsut after Selftest.

After that, it just behave as attended.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I too am getting loose pulley on Y axis and all is tight. However sometimes it does pass. Just wondering if better Y motor mount would help taking the flex out of mount and improve this self test?

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

My Y axis is also pretty random, but I do not see any step skipped, and the puley is perfectly tightened ...

My X axis is perfectly stable now. And the print I'm doing (a moai statue for my kids that wants to do decopatch on it) is preinting perfectly.

Not sure if I should loosen or tighten the Y belt, seems good to me, but apparently not perfect.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I made a better mount for the Y motor then set the belt tight. Sometimes it passes but most of the time it fails. To me it seems like a software bug. I'll be doing some more testing.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

Well got it to pass 6 times in a row now so I think I am good. I re-adjusted the pulley on Y motor so there was no deflection in the belt when it gets close to the switch. Seems any deflection adds resistance because it is so close to the pulley when it hits the end switch, not the same with the X motor.
So not a bug...thanks Prusa team for all the hard work...keep it up!!!

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

Well got it to pass 6 times in a row now so I think I am good. I re-adjusted the pulley on Y motor so there was no deflection in the belt when it gets close to the switch. Seems any deflection adds resistance because it is so close to the pulley when it hits the end switch, not the same with the X motor.
So not a bug...thanks Prusa team for all the hard work...keep it up!!!

I took a closer look after reading this and it turns out my pulley was out of alignment by about a millimeter as well. A quick readjustment and I'm now passing the self test.

Thank you Self Test for making a "good enough" setup even better! 🙂

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

Interesting, I will check that when I'll be back home, thanks for the feedback.

However maybe this test should be labelled a bit differently so that other factor (alignment, tension) should be investigated but this is definitely a very valuable test in the self-test ! Way to go PR !

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

Just a small question, but in Slic3r the first line of Gcode is
M115 U3.0.9 ; tell printer latest fw version

Does this have any affect on anything and if you used the RC1 firmware should be it be changed?

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

...I re-adjusted the pulley on Y motor so there was no deflection in the belt when it gets close to the switch...

Just finished kit...

To get past the Y-axis test I had to tighten the nuts on the front of the frame and also as above adjust the pulley to loosen the belt as much as possible but short of creating slack.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

> Just a small question, but in Slic3r the first line of Gcode is
> M115 U3.0.9 ; tell printer latest fw version
>
> Does this have any affect on anything and if you used the RC1 firmware should be it be changed?

The purpose of the M115 Uxxx code is to notify the user to install a new firmware after the drivers package has been upgraded on the PC (Mac, Linux box, you name it).

The line is ignored by the printer firmware as long as the firmware version required by the M115 code is older or equal than the version installed on the printer.

The versions may have a suffix -alpha, -beta, -rc, -rc1, -rc2, ... -rc10.
3.0.9 is older than 3.0.10-alpha, 3.0.10-alpha is older than 3.0.10-beta, 3.0.10-rc is older than 3.0.10-rc1, 3.0.10-rc1 is older than 3.0.10 without a suffix.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

Thanks for all the reports. We are listening attentively.

> However maybe this test should be labelled a bit differently so that other factor (alignment, tension) should be investigated but this is definitely a very valuable test in the self-test ! Way to go PR !

We are thankful for all the detailed description of your results. There is a very thin line between us having set the acceptance thresholds too restrictive and you having the printer built not quite ideally. So based on your reports we will likely adjust both the manual and the threshold of the self test.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

The "slipping pulley" test jerks in one direction and then it moves slowly in the other direction, thus it tries to force the pulley to slip in one direction only. The jerk is quite rapid and it has been set low enough to work reliably on the machines we built in house. Over tightening the belts may cause an excessive force on the stepper motors, so there is a possibility that at the jerk phase of the self test the motors will lose steps.

Please don't take this as an advice to loose all the belts now. Don't fix it if it works. We are investigating the issue.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I wonder if it's possible to have two phases of jerk test, one (with moderate strength ?) to test loose pulley, and one (with high strengh ?) to test belt tension.

I consider that having a way to test to validate belt tension is highly valuable, because on every aspect of the printer build, it's almost the only aspect that we do not have objective way to measure if the build is ok. Relying just on the sound of the "ping" is really not qualitative enough for first time users. Every other build aspect can be measured using ruler, caliper, or other objective mean of validation.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

The other day I decided to give the self-test another try and it started to fail on the X & Y randomly with no change on my printer.
So I decided to download the source code and look at it because I was curious and have some experience programming.
I did a modification to the code and tested it tonight and it passes every time I try it this is with the same threshold.
Basically what I did was program it the same way my GRBL based CNC router homes and finds the limits. It will move fast until the limit is hit, then backs away 5mm, then moves in slow until the limit it hit again.
I even loosened off my X axis pulley screw and it failed.
I decided to try this for my own curiosity and maybe help the Prusa Team out, I have not tried printing with this modification in yet and not if I will but it was just a test.
If the Prusa Team wants to see my mods I am willing to share them just let me know where I can post them, I feel it isn't a good idea to post them on the forum for everyone to see and try incase it doesn't work for them and damages their printer.

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I think the best choice would be to submit a pull request on https://github.com/prusa3d/Prusa-Firmware

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I confirm the final 3.0.10 if working fine now with the Y axis pulley test, well done 😉

Re: New 3.0.10-RC1 firmware for Prusa i3 MK2

I would also like to add that I was see the the "Loose Pulley - Y" errors initially after the firmware upgrade. My Y-axis belt seemed a little tighter than the others so I loosened it a single tooth and it started passing the test after that. I did check the grub screw on the motor pulley first but that was tight so I figured I'd trying loosening the belt next and it seemed to do the trick.