Ball mill reducer bearing and bearing housing, heavy, heavy duty high speed and high torque at low speed start, and vibration, the devices under radial shocks, bearings or bearing bits of metal fatigue, resulting in permanent deformation; bearing inner ring and shaft or bearings and bearing clearance occurs, resulting in relative motion wear. When this problem occurs, seriously affecting the normal production. Ball mill reducer bearing wear, traditional methods are difficult to repair such issues resolved, outsourced repair parts materials and wear size difficult to repair, often replaced with new spare parts solution; and reducer and constantly improving, accessories to update faster, keep parts take up huge amounts of money. 21st century developed the use of polymer composite materials for field repair of blessed blue mature technology system. According to the different equipment, different running different wear conditions, using the corresponding repair technology, is quick, simple and effective fix, particularly because of the deformability of polymeric materials, always maintain the 100% of the contact area, avoiding the generation of clearance, makes life even more than the new equipment after repair, solve the problem of ball mill shaft wear.