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MK3 wiggle test fails  

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andreas.j
(@andreas-j)
Eminent Member
MK3 wiggle test fails

Hi

for several hours I am stuck at step 2 - the wiggle test. No matter what I do, as soon as it comes to tightening one aluminium extrusion, the whole frame starts to wiggle 1-2mm at one leg.
I disassembled everything several times and rotated parts, no success...

before I get the axe:
is there a trick not mentioned in the manual?

Publié : 14/02/2018 12:16 pm
Neolker
(@neolker)
Membre
Re: MK3 wiggle test fails

Just don't overtight screws and follow the manual.

Publié : 14/02/2018 12:24 pm
andreas.j
(@andreas-j)
Eminent Member
Topic starter answered:
Re: MK3 wiggle test fails

If i had not done this at least a hundred times already :/

Publié : 14/02/2018 12:28 pm
GertL
(@gertl)
Reputable Member
Re: MK3 wiggle test fails

Not sure if this is your issue, but anyway..

https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/warped-front-plate-t14294.html#p65901

---
Gert

Publié : 14/02/2018 12:33 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: MK3 wiggle test fails

Try putting a sliver of paper between the aluminium extrusion and the frame,
If you insert it at the top, the extrusion will point down, and if you insert it at the bottom, the extrusion will point up.

as the end of the extrusion is quite narrow, the effect of a sliver of paper will be more significant than you would expect.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Publié : 14/02/2018 12:39 pm
andreas.j
(@andreas-j)
Eminent Member
Topic starter answered:
Re: MK3 wiggle test fails

hi all,

the frontplates seem to be OK, as far as i can see.
the problem must be elsewhere, however i cannot find it.

Publié : 14/02/2018 1:06 pm
stoofer
(@stoofer)
Estimable Member
Re: MK3 wiggle test fails

As a general tip, always tighten in opposites and a small amount at a time. So if you had 4 bolts when you look at them like this:

1 2

3 4

Then your tightening order would be something like 1, 4, 2, 3 (then again, then again, then again - a bit tighter every time). I would suggest it is possible that your first pass of tightening could be too tight, causing a skew.

This general rule does not apply if there is a more specific order, like the heated bed.

Publié : 14/02/2018 2:43 pm
Peter L
(@peter-l)
Honorable Member
Re: MK3 wiggle test fails

If you read the comments in the online instructions, a lot of people have problems with this step. You are not alone.

I had a slight amount of wiggle in my assembly, maybe 0.5mm, but I went ahead and finished the assembly and it was OK in the end. The auto-calibration can correct for some defects.

1-2mm sounds like a lot and probably worth fixing. You can try the paper trick, and someone else suggested applying weight to the frame as you tighten the screws. You can also check all the ends of the extrusions for any burrs or other defects, as that would cause a problem.

Publié : 14/02/2018 5:48 pm
HeySideburns
(@heysideburns)
Trusted Member
Re: MK3 wiggle test fails

I saw this nugget in the 2 months update blog post today that I hadn't seen before. Maybe it will help you.

"When finalizing the Y frame and tightening the front and back plates on the aluminum extrusions, do not over tighten the screws. It will cause the frame to wobble. You can also hold the extrusion with your other hand and gently twist the extrusion counterclockwise during the tightening."

Publié : 14/02/2018 8:16 pm
andreas.j
(@andreas-j)
Eminent Member
Topic starter answered:
Re: MK3 wiggle test fails

Morning all,

thanks for the tips!
The paper trick did it for me, wiggle as good as gone and the calibration reported i am "perpendicular".
So far so good, now lets go 😉

A

Publié : 15/02/2018 8:01 am
Martin Wolfe
(@martin-wolfe)
Reputable Member
Re: MK3 wiggle test fails

I had a bit of problem with this step as well. It turned out not to be my printer that was failing this test but my work bench. I moved my printer to my desk after discovering that having my printer facing left right and front back gave different results. On my desk it passed this test straight away.

So I suggest you check the level of the work surface you are using to run this test on or try several surfaces and running it with the printer facing several different directions.

Martin Wolfe

Publié : 15/02/2018 3:48 pm
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