Trident pom nut wear on rear stepper.

[evan]

Printer Model

LDO Trident 300

Extruder Type

Galileo

Cooling Type

Stealthburner

Hello everyone,

I've read a few posts here regarding POM nut wear on the tridents. I'm having a similar issue with my rear z stepper on a LDO 300 trident. I'm rebuilding the printer for the 3rd time, new printed parts, etc. While doing so I've noticed the rear stepper mount actually tilts slightly forward, especially when secured with the 2 bottom front facing fasteners. I have a 3 - 4mm difference from the centre of the leadsrew to the face of the rear vertical extrusion when measured at the bottom and also the top. Basically, the leadscrew tilts forward at the top by ~3mm.

What made me rebuild was due to the bed suddenly dropping at the back as the thread had been totally worn down. I do have my pom nuts adjusted to the point where they can easily move horizontally.

My frame is nice an square, and the rear bottom extrusion which the motor mount is attached to also is square. I'm wondering if the extrusion is somehow twisted but this seems unlikely.

Any thoughts on a solution would be appreciated. I could just not use the bottom fasteners, which brings the leadscrew back a little and hope it's enough.

Thanks!

PS. Actually, I rebuilt to add a few mods and such, but the POM nut issue is what got me started!

 

[Yeri]

Very interesting, I’ve been tracking instances of this happening and trying to find any correlations. With the bottom screws either not in or not completely tightened, the leadscrew remains straight?

Also, if you could test moving the bed up and down once it’s all assembled like that, and see if the leadscrew binds or moves out of parallel that would be very helpful

 

[evan]

Thanks Yeri. I have the lower screws just ever so lightly tigtened and the leadscrew is still slightly tilted forward by 1 to 2mm at most. Without them in, there's no difference.

I've reprinted that z mount so many times, but all seems flat with no warping etc.

Surely a few mm's wouldn't cause an issue with anything if the pom nuts have room to move ?

Will do regarding testing the vertical movement. Build progress has been slow as I'm trying to get it all spot on so it may take me a little while to test.

 

[Yeri]

Thanks Yeri. I have the lower screws just ever so lightly tigtened and the leadscrew is still slightly tilted forward by 1 to 2mm at most. Without them in, there's no difference.

I've reprinted that z mount so many times, but all seems flat with no warping etc.

Surely a few mm's wouldn't cause an issue with anything if the pom nuts have room to move ?

Will do regarding testing the vertical movement. Build progress has been slow as I'm trying to get it all spot on so it may take me a little while to test.

Thanks for the info! I agree, a small amount of movement is not going to be a problem, it will be absorbed by the pom nuts moving around.