Possible z-axis problem

[tim-antos 0]

Hi. I’ve been printing away on my ultimaker for a while now and managed to solve my issues along the way using the various forums. However I’m now suddenly having weird problems which seem to be related to the z-axis I think. I’ve scoured the forums to no avail, hoping you can help!

Essentially after printing the first few layers fine there seems to come a point where the z axis no longer moves down. The machine carries on moving and trying to deposit material however it soon starts to grind along material already laid down and is no longer able to deposit more filament as it’s flow is blocked by the solidified plastic.

I have taken some pictures to illustrate the problem.

On the left of the first pic is how the first layers should look (ignore the under-extrusion of the body – this happened as the spool jammed). On the right is how they are now turning out, note the support structure has merged into a solid. In this case I had to abort the print as it was not moving in the Z-axis at all and beginning to grind heavily across the print.

The second picture is two prints printed before and after. Not with the second the print has a lot of excess plastic on the raised outcrop and it is not as high. In this case the print actually managed to finish but not to the correct height.

I have tried all sorts of things to rectify this including:

· Tightening the coupling on the z-axis screw thread

· Levelling & re-levelling the bed many times

· Tightening & checking all grub screws

· Checking the extrusion roller and spring tension

· Reinstalled Cura and Firmware

· Greased Z axis & lubed the others

· Checked the fan’s working ok

Help would be greatly appreciated as it’s driving me nuts!

 

[illuminarti 18]

Hi Tim! Welcome to the forum!

Do you have an UltiController, or do you print from a pc?

Do you know what your steps-per-mm setting is for the z-axis?

 

[nick-foley 5]

To be clear - does the Z stepper stop turning? (meaning an electrical problem) or does the stepper keep trying to turn but the bed no longer goes down? (meaning a physical problem)

 

[gr5 2,167]

Using cura (or pronterface - it's free!) move the z axis down in 10mm steps. Measure this roughly with a ruler. Does it look correct?

Is it only moving 5mm possibly? (always consitently half the correct amount? failure mode 1)

or does it sometimes less than 10mm and then other times work fine?

Does it get stuck?

If everything is fine then rehome and move down 1mm at a time for 10 times. Did it move the full 10mm?

If everything still fine, put a ruler on the back corner of the machine as close to the bed as possible. Tape it there securely. Place a pencil or flat ruler or something on the bed so it reaches the ruler. Move the bed down in 1mm and .1mm increments. Test it carefully.

 

[gr5 2,167]

Oh and maybe you can send us a photo of your z coupler (at the bottom of the z screw).

Please answer all the questions that were in the earlier posts. They are all good questions and we need to know this before giving more advice.