UMS5 Shift in print layers

[pawcie 0]

Using S5 for couple of years now. 

No issues in general, but lately I noticed that from time to time I have prints with shift in layers.

Please see attached photo.

It should have printed perfectly round cylinder.

Any thoughts what could cause that, it doesn't happened all the time?

Its not material specific, because it happened with different materials.

 

Thx

[SandervG 1,521]

Hi @pawcie, thank you for your message and welcome to the community! Am I seeing it correctly that a layer shift occurs on both X and Y (based on the image; it shifts to the right and to the back?) 

 

Does it always occur around the same height or can it happen at any height? 

Have you ever checked if all your pulleys are still secured tightly? I don't expect this to be the case, since they usually trigger a more subtle layer misalignement, but good to check regardless. 

 

Did you ever get an ER32 or ER33 on your printer?

[AndersK 59]

Another thing to check is the fasteners for the stepper motors, if they get loose it can cause this.

Had this on my UM3 and I have to tighten them regularly, every time i do this I say to myself I should apply Loctite but then forget it 😄

[pawcie 0]

THX for quick replay.

To the question, no never seen the error and it would happen at different heights.

I'll check both pulleys and stepper motors.

[gr5 2,234]

First step is to figure out if you are slipping on the X or the Y.

 

Most likely it's one of two things:

1) Friction has increased over time.  Try cleaning the 6 rods in your gantry with some WD40, then removing as much of that as possible and applying a drop of light oil to all 6 axes and moving the head around.  Before you start notice how much friction it takes to push the head around and again after you are done.  For example can you slide the printer around the table just by pushing the head?  Can you push the head with just two pinkie fingers one on each block opposite the head?

 

2) loose set screws.  As mentioned above.  This is the most common cause of this problem but the slips tend to be more sudden (all happening on one layer).  You only have to tighten the screws on the slipping layer and it's usually the setscrew on the pulley that is on the stepper motor.