The most common quality problem is the friction between the screw and the inner hole of the cylinder when the screw is assembled, and the screw will not be rotated in the barrel when the screw is serious. The reasons for this quality problem can be found from the following points:
1. The manufacturing precision of the barrel or screw is not qualified. It is possible that the diameter of the inner hole of the barrel (or the outer circle of the screw) is poor, or the straightness and the irregularity of the cylinder, and the cylindricity does not meet the quality requirements.
2, slender screw or barrel, after mechanical processing or heat treatment, the center line appeared more serious bending deformation phenomenon.
3. The concentric error of the screw with the outer part of the supporting shaft and the outer part of the threaded part is too large.
4. The perpendicularity of the central line between the end of the cylinder and the seat or the end of the flange and the hole of the cylinder can not meet the quality requirements, and there is no guarantee of the vertical of each other. The coaxiality of the screw and the barrel is poor, and the angle is difficult to turn the screw.
