(1) The axial movement of the screw is too large.
(2) The opening and closing nut is worn, and the coaxiality with the lead screw is out of tolerance, resulting in poor meshing.
(3) The dovetail guide is worn, causing instability when the opening and closing nut is closed.
(4) The clearance of the transmission chain from the main shaft through the exchange gear is too large.
