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Problem reassembling bondtech Prusa i3 mk3  

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LtVonWitzland
(@ltvonwitzland)
Active Member
Problem reassembling bondtech Prusa i3 mk3

I uploaded a short video to help explain and is on my youtube here:

Questions:

1) There are 2 screws in the video. One seems like 1mm longer than the other - does it matter which one goes on the back part versus the door holder part?

2) Which of those screws gets the o-ring?

3) Are there torque specs for these 2 screws?

Notes:

a) Since removing and reassembling I just get clumped filament when trying to print anything. 

b) I did have a successful frog (first) print, other than the logo before I messed with the checking the bondtech alignment, as recommended in a prusa video.

c) The initial calibration / first layer calibration - seems to stick and be squished right at about -.975mm

I am not afraid to mess with stuff, but it seems fault tolerance here is more than my skills allowed for without more data!

 

Again this is new, been sitting in a box from Prusa, assembled, for a year (don't ask why). Initial setup was good, my first attempt to mess with it is a fail so far, hoping for help with these questions to get back on track!

 

Thanks ahead!

 

 

Posted : 24/12/2020 8:53 pm
LtVonWitzland
(@ltvonwitzland)
Active Member
Topic starter answered:
RE: Problem reassembling bondtech Prusa i3 mk3

Followup - after reassembly trying the o-ring on the "main" screw with the spring that holds the bondtech door in place, tried printing a frog. It starts ok, but then just clumps up to a big mess... video link here:

 

 

 

Posted : 24/12/2020 10:13 pm
LtVonWitzland
(@ltvonwitzland)
Active Member
Topic starter answered:
RE: Problem reassembling bondtech Prusa i3 mk3

bumping this, I honestly expected some form of reply by now, even granted Christmas... can anyone recommend a forum that gets more activity for Prusa printer troubleshooting?

 

 

Posted : 26/12/2020 9:02 pm
Baklin
(@baklin)
Reputable Member
RE: Problem reassembling bondtech Prusa i3 mk3

1) The screw for that is used as the hinge for the door and the screw with the spring to tension the gears are both M3x40. 

2) The manual doesn't show an o-ring for both screws. I didn't have one in my kit either.

3) There are no torque settings for the screws. The screw that is used as a hinge can't be to tight. The door has to rotate freely. The screw with the spring has to be screwed in till the head is aligned or just below the surface.

 

Have a look at the assembly guide here: https://help.prusa3d.com/en/guide/5-e-axis-assembly_28536#29984

Posted : 26/12/2020 10:10 pm
Baklin
(@baklin)
Reputable Member
RE: Problem reassembling bondtech Prusa i3 mk3

The problem with the print looks like the print comes loose of the buildplate.

Is that a print with PLA? PLA and the textured buildplate aren't always easy.  Start with cleaning the buildplate. Use dish soap and lots of hot water.

Dry with a clean paper towel and don't touch the surface with your fingers.

Posted : 26/12/2020 10:27 pm
LtVonWitzland
(@ltvonwitzland)
Active Member
Topic starter answered:
RE: Problem reassembling bondtech Prusa i3 mk3

Thanks for the pointers, I checked that link and loosened the screws as shown. Seems ok, but I am still dragging on Z and clumping. Ran calibration (17th and a half time now), and here is what I see - paper dragging but not tearing. Is that a problem? Seems like it might be I did check another link here:

 

https://help.prusa3d.com/en/article/xyz-calibration-mk3-and-mk3s_112351

 

Seems the simple sensor test is good, it shows 1 when something is below it, and 0 otherwise. Still seems like my Z may be off, unless paper drag is ok (again, paper is variable thickness I guess)....

 

Any more ideas? This sure is a rough start to a brand new from Prusa printer, where I paid the premium for assembly and stuff. Does everyone get spanked around like this? I bought into what I believed to be quality and gladly paid a premium to have a good end user experience. So far, not so much.

 

Posted : 26/12/2020 11:27 pm
Baklin
(@baklin)
Reputable Member
RE: Problem reassembling bondtech Prusa i3 mk3

If that is a build by Prusa you should contact them directly too. You get full support on the pre build printers.

 

Mine was a kit and it has worked great from the first print. Ofcourse a failed print every now and than, but that was mostly because of poor model design or lack of support.

Posted : 27/12/2020 11:16 am
LtVonWitzland
(@ltvonwitzland)
Active Member
Topic starter answered:
RE: Problem reassembling bondtech Prusa i3 mk3

"solution" found -

 

1) the re and re re calibration of the Z axis was critical, and I had to go past the point where it sticks... anyway I had to try about 47 1/2 times to get that calibration good.

 

2) loosening of the screw on the bondtech door, not too tight, not too loose.

3) MOST important which seems to be disregarded in much of the Prusa documentation where they mildly recommend it but NOT for PLA (which I am using currently) is stick glue to the surface. THAT is what fixed me after 1 and 2 where solved. Since even after they where I had bad adhesion to the first couple layers. 

 

Posted : 28/12/2020 7:34 pm
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