Z-Axis Binding on Lift and Bed not Flat

Hello,

I was wondering if I might get some assistance.

I have done all the setups and adjusted to the paper thickness. I am actually using a .005" feeler gauge which is more accurate than the paper of course. The interesting thing with my printer is that if you move to the 4 corners it is fairly accurate however there seems to be about .031" sag in the middle of the bed along the z and x axis.

Also, my z-axis is binding on lift causing it to come out of calibration. The machine thinks that it has lifted when it really has not causing the heat end to run into the last layer. I am not sure why this is.

Any one have any suggestions on these two problems?

 

Here is video of the binding.

 

Tighten your Y belt. That'll bring the center of the bed up.

 

I h ave exact same problem. Do you have your bed on rails or on smooth rods ?
When i upgraded to smooth rods (prunted parts from thingyverse) i was no longer able to apply enough tension to the belt without breaking printed parts.
The design its self did not allow me to do that anyway so:

Problem is the bed, not the belt.
Bed should be flat. It should be replaced if its not.

I contacted support for this and they dont respond anymore. Because of that, the first thing i do when i sell my ROBO is:
instead of talking good about it allover, i wont.
They replaced original broken bed with used and claimed it was new, just little dirty and dusty.
If it was new, it would not have print marks on it and worn out wires contacts. It was also scratched at the bottom and to this day its warped just like yours and i can do nothing about it.