Flexible coupling issue

[tpeyron]

Hi all,

I'm having trouble with the Z axis coupling : facing the printer, the left coupler always giggle when it comes to auto home position.

I've already done the following :
- file the threaded rods holes => I've done that
- z-axis threaded rod is bent, if it is bent, it needs to be replaced in time; => There are perfectly flat
- coupling is installed correctly; => I've tried several different settings, but none worked
- the left and right of the z-axis are on the same horizontal line, and adjust it in time if it is tilted; => It's part of my calibration routine
- the brass nut installation is too tight. If it is too tight, it needs to be loosened. => II did it since I saw it on the forum (only 2 screws are present, quite loosened.


The first milimeters are crap, but after this, the print is quite good. And no matter what I do, it's always the same coupling that does the flex.

I was wondering if switching the couplings for non flexible ones would work ?

Cheers,

[William]

Hi, Not recommended to be replaced,
You can check if the left coupling is installed correctly,
How does it sound?
You can provide specific videos so that we can better solve the problem.

[tpeyron]

Hi William !

Thank you for the reply, and I apologize for the delay of my response.

I finally solved my problem, and I'll sum up what I've done here, hoping it might help the others :

I've had an issue with the left coupler of my Z-axis. In fact, reaching the "auto-home" position made it extend itself much more than the other one. Consequently, no matter how precise I levelled the bed with the X-axis, the "auto-home" position was never the same.

As I said in my original post, I thought the best option for me was to change the couplers for rigid ones. So I investigated, and realized that this change was not common, so I abandoned the idea.

Trying different settings for the 3D printer, I realized that the flexing was not an issue when the bed was levelled at around 1.9 mm (from the top of the underlying platform to the top of the glass on the heating bed), so I modified the Z-level screw as follow :


I removed the spring, and replaced it by a nut (otherwise, it was too much compressed. Thought, I found the original system with the spring too loose for a perfect setting).

And so now, everything is fine

Cheers,

[William]

Hi,thanks a lot for your feedback.