Z-axis problem at specific z-heigt

[murtang 0]

Hi

I am having a problem with my UM2+ with the z-axis. The first centimeter or so of layers are fine but further up I am getting a layer which is barely there making a very weak point. I have printet a couple of objects and it seems as it is at the same z-height each time the problem is. I have attached two pictures of the problem.

Any clue to what is wrong?

[chrisw 70]

I would first try powering off the system, then raising the build plate all the way up. To raise it manually just grab under each side of the bed support plate, just in front of the "Ultimaker 2" sign. It should have some even resistance all the way up. Then when it's fully up, release it. If everything is perfect the bed should slide back down to the floor from its own weight. Most machines that I've worked with need a little extra pressure though. If it doesn't slide down by itself, try helping with a light push.

On its way up and down the motion should be consistent. If you feel bumps or extra drag at those specific 2 points, then it's probably either a damaged z screw, rod, or bearing, or maybe just something that needs to be cleaned out.

Also, what does it sound like when the power's off and you're sliding the bed up and down? Smooth or grinding sounds?