UM1: first layer height problems

[mihc 0]

Hey,

After printing normally for a month since I bought it, suddenly one random print went totally wrong, when the nozzle started to print aprox. 2 mm apart from the bed.

I started the bed levelling wizard to make sure if I accidentaly moved the bed while removing the last finished print, but the settings were the same as I remembered ( less than a milimeter away from the bed in each corner).

Any ideas what might have gone wrong?

Miha

 

[Dim3nsioneer 558]

Is it possible that the upper z end switch shifted down somehow? Then the stage would stop earlier which would result in a large distance between nozzle and bed.

 

[mihc 0]

When the bed is moving to it's place on the Z axis before the print, it sounds like it pauses one or twice and I suspect that because of it, it doesn't achieve that hight it was supposed to and starts a milimeter or two lower. Just enought that the PLA does not stick to the surface of the bed.

 

[illuminarti 18]

When you level the bed, the nozzle needs to be touching the bed, not 'a mm or less from it'.

It is also possible that you are skipping steps during the move... you might check for any debris in the threads of the z-axis screw, and also lubricate the screw using some of the green grease that came with the printer.

I recommend connecting to the printer over USB using Pronterface or a similar program, and manually moving the bed up and down at various speeds to see what is happening.

 

[gr5 2,247]

But when you did bed leveling it does the exact same homing procedure. So it could be:

1) Z switch is intermittent and not hitting consistently.

2) This "pause" sounds like an issue. Maybe the Z coupler is loose? Maybe the current to the Z stepper isn't enough to move it. Ideally you should turn off power and spin the Z coupler by hand. It should move quite easily. Make sure you put a drop of the green grease on the Z screw and put a drop of light oil (any light petroleum oil will work but best not to use one with additives or cleaners (like wd40 isn't ideal)) on each of the vertical rods.

Then move the bed up and down multiple times.

 

[gr5 2,247]

pronterface is free, easy to use gui and is here:

printrun/pronterface download:

http://koti.kapsi.fi/~kliment/printrun/