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Help - My printer is skewed!  

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adrian.s2
(@adrian-s2)
Eminent Member
Help - My printer is skewed!

Hi,

I had the original Prusa i3 and decided to get the Mk2 upgrade when it came out.

As anybody will tell you that has done the upgrade, it's more of a tear down and re-build.

In that process, some 'mis-alignment' may have happened.

Now, my printer prints perfectly and I have no issues but when I do the calibration sequence, at the end it always says that my printer is' severely skewed' and that it will magically fix it for me. (Which it does!)

So..... How badly skewed does the printer have to be to get that message? Are we talking millimetres or micrometres? Are there other messages that say 'Partially skewed' or 'Barely skewed'

Would it be worth pulling my printer apart and re-aligning things.? I suppose you could say that I've got 'Printer alignment anxiety' if that's a thing. 😆

Thanks for any advice.

Posted : 20/02/2017 9:23 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Help - My printer is skewed!

Hi Adrian,
It's probably now worth pulling it apart, just check the distance from the back of the main frame, to the rear corner pieces , on both sides. it is likely that one length is shorter then the other.
I believe this length should be 100 mm.
if it's out, adjust as required, then when tightening up after adjustment make sure that the 10mm screwed thread bars rest firmly in the bottoms of the cutouts in the main frame, and that the four corner posts to the threated rod chassis are all resting firmly on your table.

re try the XYZ calibration, and hopefully all will be well

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

Posted : 20/02/2017 11:35 am
adrian.s2
(@adrian-s2)
Eminent Member
Topic starter answered:
Re: Help - My printer is skewed!

Thanks Joan,

You've talked me into it!

I will have a play tonight and report back.

Posted : 20/02/2017 1:02 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Help - My printer is skewed!

Hope all goes well for you.

I got a congratulations. X&y perpendicular message. Hope you do too.

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

Posted : 20/02/2017 5:37 pm
adrian.s2
(@adrian-s2)
Eminent Member
Topic starter answered:
Re: Help - My printer is skewed!

Well,

After about 4 hours messing around, I managed to get the geometry (almost) correct.

The calibration now says "X/Y calibration alright. Slightly skewed"

Without tearing the printer down completely I think this is the best I will get.

I just loosened all of the nuts and heard a few creaks and groans as things relaxed.

Measuring things, one arm was out by around 2mm compared to it's counter part. Measuring from the main frame forwards, towards the LCD.

This was putting a slight twist on things.

After re-tightening everything, that's the best result I can get.

Everything measures out perfectly but something must still be very slightly out.

Anyway, my goto calibration stick has just printed out perfectly so I think I will leave it at that.!! 😆

Posted : 22/02/2017 12:29 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Help - My printer is skewed!

Hi Adrian, you are supposed to measure from main frame backwards... away from the LCD

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

Posted : 22/02/2017 12:37 am
adrian.s2
(@adrian-s2)
Eminent Member
Topic starter answered:
Re: Help - My printer is skewed!

Hi,

Yes, from the frame to the back of the printer was bang on, on both sides.

Measuring forward from the frame to the front threaded rod supports was out by a few mill on one side.

So I think that front corner was getting pulled out of square.

Posted : 22/02/2017 9:08 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Help - My printer is skewed!

Okey Dokey...
🙂

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

Posted : 22/02/2017 11:31 am
adrian.s2
(@adrian-s2)
Eminent Member
Topic starter answered:
Re: Help - My printer is skewed!

I finally got the "Congratulations" message after a bit more fiddling.

It turns out that the Y Frame was riding high about 1 mm in the main frame.

Loosening the bolts, I felt it move the tiniest amount.

Re-assembled and it calibrated OK.

I've got to say that the prints seem to be coming out slightly better than before (and they were very good anyway) when I was getting the 'Really skewed' message.

Definitely worth the messing around.

Posted : 25/02/2017 6:05 pm
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