How to properly clean Z-axis?

[Giddi 6]

I am experiencing some problems regarding the z-Axis of my UM2. First I had skipped layers and now banding gets worse and worse. When I move the bed up and down manually, can feel resistance almost every 1-1,5 cm. I already tried cleaning it with a simple cloth and afterwards regreasing with the provided grease, but it didn´t help.

Is there some way to completly clean the Z-axis? Special cleaning solution? special cleaning "brush"? Do I have to change the bearings?

[Labern 774]

Having a bit of new grease will loose any dry bits and help with cleaning. You can hold a cloth on the screw near the build plate and raise the build plate with the other hand. This will make the screw rotate and help in wiping inside the threads. You can then use a clean piece of cloth and do the same underneath. Then apply a small amount of new grease.

I think your problem maybe with the linear bearings on the 2 guide shafts. Do not grease these but you can test them to see if one is causing your issue.

You need to remove the cover and unscrew the bearing from the build plate. then slide just the bearing up and down the shaft to see if there are tight spots.

To change the bearings you unscrew the black plate underneath the machine and slide the rod out. then you can remove the bearing.

[peggyb 169]

and check if your z-nut has any play.

Changing to a proper z-nut can fix your problems.

If the z-nut has some play and the bearings 'hang', you will get banding. You can simulate this by pushing a little underneath the bed when the bed moves to the next layer. The next layer is printed on the same height as the former layer due to the play of the z-nut, until the end of the play is reached. I think you can have crappy bearings with a good working z-nut....

I bought some at http://www.technobotsonline.com/tr8x2-travelling-nut-for-threaded-rods.html

[neotko 1,417]

I think you can have crappy bearings with a good working z-nut....

Totally true. But also, on my umo+ that I changed the bearings for misumi (the cheapest model) and now it moves like silk. But true, if the bed nut haz close to zero play it can move the bearings no matter what and the z 'fall' disappears, but (before changing the bearings) I saw some visible differences when doing small layers like 0.06, there was a small banding on the bad areas, for 0.2 layers the banding did banish.