linear bearing wobble? how much is too much

[Toby Hope]

Hi, I have recently noticed wavy lines when the laser goes around a corner it affects the horizontal lines more, almost like a car going to fast then trying to correct itself...

as the wobble is mostly noticeable the y direction I went to give the head a wiggle and sure enough there's an amount of slack and I hold my finger under the linear bearing I can feel that the movement is coming from the bearing not from any of the adjustable head brackets..

just wondering if there should be ANY noticeable slack in the bearing at all (I figure there must be some others it would find moving very hard).

I have checked mirrors and lens for secure fitting and as the wobble increases with speed I'm thinking this points to some slop somewhere rather than a rattle? but not sure tbh.. I've attached a pic where I have scribble the speeds under each target, I normally cut at 10 mm/s and as 20 is a satifactory result it's not a major issue.. BUT I like to '"cut" engrave for speed, so it would be nice to be able to cut engrave at 100mm/s so I'd look to remove the wobble if I can.

any help appreciated!

thanks Toby

[Toby Hope]

[Frank Small]

Toby

In my opinion there should be no wiggle on the slide. Once you get movement there it multiples the error (distance from the slide to the work) and will show upon the work.

[Pete Cyr]

Zero. Linear bearings should only move along the axis of the rail. You typically need very precise measuring equipment to measure movement perpendicular to the rail....unless the bearing is jacked......you certainly should nor be able to see it by moving it by hand or as it runs

[Toby Hope]

great, thanks for the reply, that’s hood news hopefully the bearing is worn and replacing will sort it.

if any recommendations for 15mm bearings that would be good, i’m sure i’ll find some but i’ve seen various qualities so far

[Pete Cyr]

I can recommend HIWIN - but I would replace what is installed.
HIWIN bearings shown belwow

linear-guideways-large.jpg

[Toby Hope]

I can recommend HIWIN - but I would replace what is installed.
HIWIN bearings shown belwow
linear-guideways-large.jpg

thanks i was just looking at these

[Gene Uselman]

I think that the wobble is probably something else personally- check for a loose lens for instance.

[Toby Hope]

I think that the wobble is probably something else personally- check for a loose lens for instance.

Yeh first thing I checked was lens and then mirrors, but when I wiggle the head it flops back and forth on the 'roll' direction which is where the wobbly line is coming from.

I can also see the detritus which is very close to the rail attached to the bearing wiper move with the bearing and head when I wiggle it.

[Doug Fisher]

Just to make sure before you pay $$ for new rails, since this issue occurs at a direction change, are your belt tensions are correct? Additionally, if you have unnecessarily overly aggressive acceleration (many come from the factory with this set too high), have you tried lowering it? Search the forums here and at LightBurn forums for discussions about these issues.