Z Axis backlash

Hi all,

I just upgraded my Foldarap 1.0 to 2.0. I was really not confident in the X-axis rack concept, but it DOES seem to work, so I have to say: "congratulations Emmanuel!".
But I do have a problem. I have nearly 1mm backlash on the Z axis (i.e., when I drive down to find my 0, I have to drive up nearly 1mm for the Z axis to begin to move).
Has anyone else had this problem?
How are you supposed to mount the Z axis? By screwing the threaded bar through, or by preparing your screws and the pushing the bar in from the side? (I tried both, but with no success). And how tight must the screws be? Must you hear the plastic crack when you slide them in? (tried that too, but then the axis stalled - as expectable).
I also pu some oil on the Z axis extrusions to help, but I didn't see a difference.
Actually I switched to this version, because I think my Z axis didn't have smooth progression - I suppose because of dry friction.

Cheers,
Jérôme.

Jérôme,

How smooth is you axis movement? Does the Z axis move downwards without the threaded rod by itself?

It may be that your z-axis parts are a little too tight. Gravity is the best method for z-axis backlash compensation. Or you z-axis rails aren’t perfectly parallel.

Conoral11

Hi conoral11,

Thanks for your clues, I'll check that and tell you what I see.
Is the Z axis supposed slide down the whole way on its own when you disengage the threaded rods?

Cheers,
Jérôme.

Jérôme,

Yes they should if gravity is compensating for backlash. Be careful not to make your plastic parts too lose, because they can then twist causing it to bind and get stuck.

If you get the time take a video of the plastic parts sliding by hand. It should give a clue to how tight your parts are.

Another option is to place a spring between the two nylon nuts in your z axis. This would ensure that your top nut is pressing again the top of its little hole. Tell us how you get on .

Conoral11

Hi all,

Ok after changing my steel nuts for nylon and reprinting the latest Z-axis sliders (with the small "pads") - and filing the parts a little bit, my Z-axis has now no backlash anymore. Thanks for you comments.

Cheers,
Jérôme.