I have an issue with my M300. It seems that the ball screw / plateform does not move freely. As far as I remember, when you shut down the printer the platform should go down by itself. right? On mine, it stays where it is. Do you have any advice on the maintenance I should do? For information, I put silicon lubrication on the screw, I saw afterwards it was not recommended. Does it damage the printer?
the platform in the M300 is quite heavy, so yes, it should go down by itself after turning the printer off. Please have a look at these screws - they should not be fully tightened, ensure they are loose:
Also, what happens when you move the platform up and down through the menu? Does the platform move at all, or do you hear some noise? Please take a video.
As for grease - we recommend using silicone oil, so you definitely did not damage the printer.