After repairing or manufacturing the extruder screw barrel assembly, the common quality problem is that the screw has friction phenomenon in the rotating surface of the barrel, and more serious is that the screw cannot rotate within the barrel. If this quality problem occurs. The following points can be analyzed and found.

1 The manufacturing accuracy of the barrel or screw is unqualified. It may be that the diameter of the bore (or the outer diameter of the screw) of the barrel does not match the required tolerance range, and there is a large overshoot or roundness of the screw. There is a serious overshoot in cylindricity.

2 After the heat treatment of the slender screw or barrel bore, the axis line shows more severe bending deformation.

3 After the support shaft and the screw that are assembled with the screw are assembled, the error of the coaxiality of the axis of the two parts is larger.

4 The squareness of the squareness of the centerline of the inner hole of the cylinder bore and the end face of the cylinder barrel and the base, or the flange end face, is relatively large.