Extruder goes to far from platform

[iesvilla 0]

I've been having a problem, after some successful prints. I've leveled the bed multiple times, but every time I try to print, the head goes to home, moves, and winds up about 0.5 cm too far from the print bead when it starts to print. I've adjusted the endstop multiple times, same with the height of the build area.

Any thoughts?

 

[gr5 2,172]

Can you show a very short video of the problem? Low resolution, 20 second video should be enough.

 

[iesvilla 0]

 

Tried some uploading. Also uploading to youtube in case it doesn't work.

 

[gr5 2,172]

Wow! I have never seen that before. And I've seen a lot.

I think your Z stepper is slipping somehow.

Is the z screw firmly seated into the Z coupler at the bottom of the z screw? Look at the first 2 pictures in this post:

http://umforum.ultimaker.com/index.php?/topic/2216-strange-print-artifacts-horizontal-bands-rippling/?p=15659

The first picture shows *good* z screw insertion. The second picture shows *bad* z screw insertion (sticking out).

More likely you are slipping on the motor shaft. Try tightening that bottom screw quite a bit. The set screw that connects the coupler to the stepper motor. Tighten it much more than you think it needs to be.

You can test things by homing, and then moving Z up and down by 10mm. You can do this with the ulticontroller or with the Cura print window. See if the screw is truly moving up and down by 10mm. If you install pronterface (it is free) you can adjust acceleration settings for the Z axis. Maybe you have too much friction in the z screw for the default acceleration. Although if it were me I would fix the friction and leave the z-acceleration alone. If you *do* change the z acceleration remember you have to save it to eeprom or you will lose that value the next time you power off the Ultimaker.

 

[iesvilla 0]

Turns out that was it, which is weird considering i had already printed the ford motor from thingiverse with great ease. thanks a lot :-P