Migbot Prusa I3 Z axis problem

Hello everyone,

I received a Migbot Prusa I3 (the 3D Electron sold by 3D Printers Online Store).

There is a problem with the Z axis: the nozzle can go down but can not go up.
In the descent's direction, engines make a little noise, as if there was resistance. In the ascent's direction, engines produce even more noise and do not move.

This problem is not systematic: after setting precisely the parallelism of the two trapezoidal rods there is no noise or resistance, nor up or down, but after a few movements, the problem reappears.

This can happen at any level of the axis, at the top, bottom or middle, randomly.

If I remove the Y axis, and that there is no weight on the Z axis, there is no noise or resistance: everything works.

I tried to change the value of the potentiometer of the RAMP's Z axis (see picture), but without success. By default it was 0.8V. I tried to change several values ​​between the minimum (about 0.150mV) and maximum (about 1.8mV).


I made a video for you can see (and hear) the problem : [youtu.be]

I can not even count the hours spent trying to solve this problem. Any help would greatly appreciated. Thank you in advance

PS: Excuse my English, it's not my native language

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Printer: Migbot Prusa I3 (3D Electron)
Electronics: MKS Base V 1.2 with preinstalled Marlin

Could be a bearing binding or perhaps the shafts slipping. Give the bearings a light oil or replace, check the couplings for correct installment.

Edited 2 time(s). Last edit at 05/02/2016 10:58AM by gotswrv.

Thank's for the answer. It's already correctly oiled. What should I check on the couplings ? It seem ok for me.

did the z axis able to move by finger lifting? if so then somethings not right on the z motor or z stepper motor.

If I understand well (like I say, English is not my native language), you ask if the Z axis move up when I push a little to help it ?
If so, the answer is yes, as you can see in the video that I posted in my first post.

So you think one of the two Z motors is faulty, or not enough powerfull ? If it's a power problem, increase the value of the RAMP's Z axis should have fixed the problem, dont you think ?

Edited 1 time(s). Last edit at 05/03/2016 05:26AM by Xav987.

@evetanlm, @gotswrv, @everyone else ? Any idea ?

sorry just saw, ok, as i see the video the fault have a few possibility, will you be able to take out the leadscrew and just move the motor and make it to video for me to see whether can it move itself? second if i'm not wrong another possibility is the program issue. take the video first and send to me. thanks u

Thank you again to taking time for me.

What you call leadscrew is it what I call trapezoidal rods? Like that : [upload.wikimedia.org]
The two Z motors can move well if they're not bind to anything.
I will able to make a video in a few hours.

ok. after you upload, hope i was not in bed, as time zone different, now my time is 8.03pm

I hope it's not too late for you. Here is the video :
[youtu.be]
First in the ascent's direction, then in descents direction.

Ok. So stepper seem fine to me. Now the problem is only program. You are using migbot? Can send me the firmware you using to evetanlm at gmail dot com

The firmware was preinstalled on the MKS Base V 1.2 motherboard when I receive it.
I don't have the sources, but it is a Marlin with custom configuration.
I can't be sure, but I think the configuration is this one : [forums.reprap.org] (see the second post).
Do you know if I can decompile it directly from the motherboard?

Give me eight hours when i reach office then send you the migbot software I'm using sorry real tired as now is 12.20am in my side. Sorry

Ok, thanks a lot!

Sorry out in another forum, [drive.google.com]
[forums.reprap.org]

Thank you, but with your firmware, I have exactly the same problem. I think I will try to buy new Z motors. I have no others idea.

Xav987, parles tu français?

Si oui, j'ai eu un problème similaire. J'ai simplement enlever 2 vis sur 4 (de chaque coté) sur les écrous en laiton fixés les pièces en plastique.
Pour ma part, le fait qu'il y ai les 4 vis bridait de travers l'écrou sur la vis trapézoïdale.
Depuis, plus de problème.

I had a similar problem. I simply removing 2 screws on the 4 (on each side) on the brass nuts attached plastic parts.
For me, the fact that there have bridled the 4 screws through the nut of the trapezoidal screw.
Since then, no problem.

wait wait don't buy first, maybe they use different motor. send me the picture of your motor

3d printing is not about buy and spent, it's about creative and problem solving.

Quote
Ceax
Xav987, parles tu français?

Si oui, j'ai eu un problème similaire. J'ai simplement enlever 2 vis sur 4 (de chaque coté) sur les écrous en laiton fixés les pièces en plastique.
Pour ma part, le fait qu'il y ai les 4 vis bridait de travers l'écrou sur la vis trapézoïdale.
Depuis, plus de problème.

Oui, je parle français, je vais essayer ça, merci.

mine did the same turned out to be an uneven x axis