Z axis goes down into board during point 4 of 4 in XYZ
 
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Z axis goes down into board during point 4 of 4 in XYZ  

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brad.h9
(@brad-h9)
New Member
Z axis goes down into board during point 4 of 4 in XYZ

Built an MK3 kit and have been running into an issue with XYZ calibration. During calibration point 4 of 4 in the first round, the z axis motors dig down into the bed as hard as they can. As a result, as soon as it starts to move again, it drags the paper and the printer needs to be stopped. The other points are successfully working but point 4 is causing issues. The PINDA probe has its led not showing during this so I'm not sure why the motors would move down if the probe is saying there's metal directly beneath. I've recalibrated the PINDA probe several times with different methods (zip tie/dime, credit card). I also performed a factory reset to no avail.

I was considering flashing the firmware again but can't find a link to the 3.1.1-rc1 b121 firmware. I also noticed some other issues with the printer crashing after completing self test even though I was running the wizard and expected it to go to calibration next.

Edit: Just noticed I should've posted this in the Prusa i3 kit - Building, calibrating, first print, maintenance, ... board 😯 🙁

Also to clarify, when I was saying the z axis motors pull it down 'as hard as they can', I meant that the motors are running for 5-10 seconds continuously trying to pull the axis down and are stalling after the first second or two.

Thanks for your help 🙂

Posted : 10/12/2017 3:28 am
brad.h9
(@brad-h9)
New Member
Topic starter answered:
Re: Z axis goes down into board during point 4 of 4 in XYZ

Video: https://streamable.com/pwe0e

I'll keep trying to calibrate the PINDA probe but I'm not certain it's the cause.

Posted : 10/12/2017 4:49 pm
shortgiraffe
(@shortgiraffe)
New Member
Re: Z axis goes down into board during point 4 of 4 in XYZ

I have a similar issue with my MK3. Just after the 4th point is finished in the XYZ-calibration, after a brief pause of a few seconds it suddenly crashes into the heatbed. The display then shows "Improving bed calibration point 1 of 4", but I quickly turn the machine off afterwards, so it's only displayed for a split second. With my issue it doesn't just pull down though, it also tries to move around after crashing into the heatbed.

I've tried moving the PINDA probe both up and down, too far up and the system test fails, further down and I still have the same issue. I've also talked with support and tried the b125 firmware without it changing anything.

That being said, the 9-point calibration still works as it should and I get decent prints even though the setup wizard has never been completed. The Benchy turned out almost flawless.

I would like to solve this though, so any help would be greatly appreciated.

Posted : 10/12/2017 6:46 pm
Ray Semenoff
(@ray-semenoff)
Active Member
Re: Z axis goes down into board during point 4 of 4 in XYZ

Me too!

Just finished building my MK3 and it "goes crazy" after finding cal point 4 - pushing the hot end down into the bed - even bending the bed (lots of force)!

I've moved the PINDA probe up/down with no improvement.

I'd like to get beyond this point and finish the XYZ cal, but I'm afraid of damaging the machine before the first print.....

Posted : 16/12/2017 12:56 am
shortgiraffe
(@shortgiraffe)
New Member
Re: Z axis goes down into board during point 4 of 4 in XYZ

Let's hope it's just a firmware bug. Edit: Nope, much better, just my own stupidity!

I still haven't managed to solve the XYZ-calibration issue, but printing works just fine here after all. Just do some live Z-leveling and 9 point calibration and hopefully your printer will work fine too.

Posted : 16/12/2017 1:04 am
ibn
 ibn
(@ibn)
Trusted Member
Re: Z axis goes down into board during point 4 of 4 in XYZ

which version of the firmware are you using?

this is from the download page, see last line:

Firmware 3.1.1 RC1 b122 (December 12, 2017)

MK3 only.

prusa3d_fw_3_1_1_rc1_b122.zip
Changes in 3.1.1 b122 RC1:

Initial MK3 release
Fixing XYZ calibration crashing from b121

Posted : 16/12/2017 1:22 am
Ray Semenoff
(@ray-semenoff)
Active Member
Re: Z axis goes down into board during point 4 of 4 in XYZ

Found my problem - OPERATOR ERROR!!!

Turns out I had the filament holder attached to the upper (horizontal) frame backwards.

On the XYZ calibration, the upper stops were NOT being hit - the spool holder was in the way and acting as the Z axis stopper!

Once I removed the spool holder and did a quick check that the Z access moves freely over the entire range of vertical travel, the calibration is much happier!

I feel really dumb now.....

Posted : 16/12/2017 1:31 am
shortgiraffe
(@shortgiraffe)
New Member
Re: Z axis goes down into board during point 4 of 4 in XYZ


Found my problem - OPERATOR ERROR!!!

Turns out I had the filament holder attached to the upper (horizontal) frame backwards.

On the XYZ calibration, the upper stops were NOT being hit - the spool holder was in the way and acting as the Z axis stopper!

Once I removed the spool holder and did a quick check that the Z access moves freely over the entire range of vertical travel, the calibration is much happier!

I feel really dumb now.....

Oh my, you're entirely correct, that was my issue too. No idea how I missed that, at least you managed to make me feel dumb too... 😀 Calibration went flawlessly when I turned the spool holder around!

Posted : 16/12/2017 2:16 am
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