Z Axis won't go to the top  

Re: Z Axis won't go to the top

Hello Keri,
first try to switch to high power mode and unscrew the tension screws in X-end_idler. If it does not help double check that trapezoid motor nuts are not misaligned.

Re: Z Axis won't go to the top

Thanks for the suggestions!
I had no idea what those tension screws did, but now they make sense. I scraped out some of the printed part on the top left corner to allow the screw axis to move more freely. I did take your advice and adjust those tension screws. I was already in High power mode.
Thanks

Re: Z Axis won't go to the top

I'm having the same issue. Did you resolve it?

Re: Z Axis won't go to the top

I'm having the same issue. Did you resolve it?

Can you try mounting the trapezoidal nuts other way around? It should give them more freedom into the right place.

Re: Z Axis won't go to the top

Here's a video. Which nuts are you referring to? The black one you screw onto the motor? I tried loosening them, but I can try flipping them over as well.

edit: Okay, loosening those black nuts on the motor seems like it might have helped. It's still acting a little funky, I'll upload a new video in a moment.

Re: Z Axis won't go to the top

Okay. So I think I have it working correctly.

1. Loosened the black nuts on the motor screws
2. Retightened the trapezoid nuts that go into the orange pieces on the x-bar
3. Manually threaded the Y motors all the way up
4. It seemed a little better, but still was acting similar.
5. Noticed that the screw that holds the top corner piece on wasn't threaded in straight, it was lower than all the rest of the screws. Fixed that
6. Decided to try switching the two plugs for the Y motors on the RAMBo board (saw someone alluding to testing this here: https://www.reddit.com/r/3Dprinting/comments/4n27rh/prusa_i3_mk2_error/d43cbvd figured it was worth a try)
7. It was immediately better, I don't know enough to say if a random tweak of a screw made the difference or switching the plugs around.
8. Did multiple self checks and Y axis move tests to confirm that it's functioning properly, which it seems to be so far.
9. I notice that the sound changes as it gets to about 3" from the top of the travel.

Here is a video of me testing the Y axis after a successful Self check:

Re: Z Axis won't go to the top

I had the same issue. It appeared as though it was binding. After measuring the distance of the smooth vertical z-axis rods, they were over 1/4 inch wider at the top. I loosened the x-axis smooth rod adjusters, did not help.

I disassembled the x-axis chassis and noticed one smooth rod was longer than the other. The printed bore for one of the smooth rods was pretty tight so I twisted the rod while "manipulating" it further into the bore.

The top z-axis printed fittings still took a bit of force to line up with the aluminum frame, but at least the rods aren't visually bent anymore.

Reassembled and then everything lined up and z-axis functioned properly. X-axis chassis went all the way to the top without problems. No significant measurable distance between lower and upper rod locations.

Re: Z Axis won't go to the top

Does this look like what you experienced?

left side -

right side -

Re: Z Axis won't go to the top

So it looks like no matter how much fiddling I do, the left side of the y axis is about 1mm off from the right side. At a loss at this point.

Re: Z Axis won't go to the top

Yes, but mine would stop about an inch from the top before the motors started stalling.

Maybe try measuring the distance between the smooth rods at the bottom, then at the top to see if they're parallel.

Re: Z Axis won't go to the top

I'm having the same issue. Did you resolve it?

Can you try mounting the trapezoidal nuts other way around? It should give them more freedom into the right place.

What do you mean by "other way around"? That's not clear to me.

Edit: I think I finally fixed my issue. I loosened the trapezoidal nuts, gently pried them out of the 3d printed part just slightly and then reset them with the screws, alternating between the two evenly. I used only very, very light pressure with the screws to secure them. That 1mm difference seems to be gone!

Re: Z Axis won't go to the top

What do you mean by "other way around"? That's not clear to me.
Upside down. But pay attention to mounting holes, two holes are bigger then others, choose smaller ones for mounting screws.
This position of trapezoid nuts solves the issue with small holes in printed part. When you force the nut into smaller hole, it squeezes and makes a lot of pressure to trapezoid screw. It induces too much drag which the motors cant handle and stall.