Wobbling printer head fixed in 5 minutes?

[hp-65 4]

Yesterday, I replaced the linear bearings in my old Ultimaker "Classic", one

of the first beta machines. That was badly needed.

Well, after 2..3 hours of dis- and reassembling everything, accompanied by

several loud curses, as well as general swearing, the moment of truth:

Y axis ok, Y still wobbling exactly as before :-/

Ok, maybe just bad luck. Buy 10 bearings to find the one that's good.

And actually, all my UM2s proved that theory. Most of them came with

wobbling heads, straight from factory. Others, like one of my Go machines,

in daily use for about a 3/4 year, are still perfect.

But today, a new thought came to my mind:

Does the angle of fitting that part probably play a role here?

Can it be fixed by rotating the linear bearing?

To find out, I quickly designed a little "bearing pusher"

And _carefully_ rotated the bearing with pliers.

Bingo! As if it's a new machine.

Well, er, okay, those parts actually were new, so I tried the same with

an UM2, without replacing anything - and yep, same result...

No wobbling.

So as it seems, we have a quite good chance of fixing a wobbling

printer head, by doing nothing else but rotating the linear bearings.

\o/

===

BTW.:

Is that forum design a bug or a feature?

Edited January 6, 2016 by Guest

[Labern 772]

 

@Didierklein once mentioned that the linear bearings are meant to be aligned so the ball bearing races are X shaped not + shaped. This will help with the loading applied to the bearing.

[DidierKlein 729]

@Didierklein once mentioned that the linear bearings are meant to be aligned so the ball bearing races are X shaped not + shaped. This will help with the loading applied to the bearing.

 

Yes! It's something i was told at the Ultimaker HQ during a training, the linear bearings have four lines of balls. It's advised to put these lines in an X shape rather than + (from the point of view of the buildplate.