ribbing - all around

[3drob]

Hello my name is Rob new here on the forum (hello everyone!)
a friend of mine has a Geeetech Prusa i3 Pro B MK8
and because I have built two printers myself, I help him to startup.
the printer had some problems with extruding but now SEEMS to be okay.
a somewhat different problem is that with the 20X20X20 cubes
around the sides ribbing (as an accordion but then on his side!)
on the sides front-left-right and behind.
all around but not above and below.
I think the GT2 strings are tight enough!
does anyone know how I get rid of those ribs?

friendly greetings from The Netherlands!
Rob.

[K1Tt]

Hello Rob
I have also I3 pro B and had same problem with Z axis. The problem is connection between coupling and lead crew rod on both Z motors.
When i measure hole diameter in the couplin was exactly 8mm, but the lead crew rod had only 7.8mm. The lead crew rod is fixed in the coupling by two small worms and when it tightens then lead crew rod will come out of the center. You can fixt this problem delimiting the gap in the coupling, or print new antivibrating holder somting like this https://www.thingiverse.com/thing:808509

[3drob]

Hello K1Tt
thank you for your comment!
yes I myself have also been looking and that M8 screw thread
it seems like it has who has a drink too much! ;-)
so yes I could agree with that!
but you also have problem with the back and also the front?
I did not expect that!?
we are going to look at it!

thanks again for your response and
the friendly greetings from the Netherlands!
Rob.

[K1Tt]

Yes i had problem on all 4 sides. Bottom and top side was ok. If you have side ribbing only on left and right side then is possible that is some screw poorly tightened on X axis, or low tension belts. But if you have problem with all 4 sides it is problem on Z axis.

[3drob]

Hello K1Tt,
Okay we (that friend of mine) are working on it.
we also attach the printer to a bottom plate (a table)
As soon as I have time again I will look at him again,
but he must also do more himself (I'm letting him swim for a moment!)
(of course in the positive way!)

once again thank you that you have reacted for a moment, I am very grateful for that!
I will link back what happened!
kind regards from Rotterdam!
Rob.

[3drob]

[attachment=0]IMG-20180330-WA0010.jpg[/attachment]
and see the differences!
Z axles adjusted and a new 0.4nozzel turned in,
that is the only thing that has been done!

friendly greetings from The Netherlands