Hello. I have a problem with my printers z axis. Step motor conntected to a 8mm threated rod with a 5 to 8mm coupler. The platform holding the bed moves downward smoothly in first 10mm. After that the platform resists to move for a while then drops 1-2mm to where it should be. The problem repeats in different heights. I have changed the threated rod but the problem persists at the same points. What can i do for that. It ruins my prints. Here is the video of moving platform.
https://youtu.be/pRzSH5WkNy0
