There are many factors that cause the failure of mechanical parts and are more complex. They involve the structural design of parts, material selection, processing and manufacturing of materials, assembly of products, and maintenance and other aspects.：
1.Unreasonable design: Mainly refers to the incorrect or unreasonable structure and shape of parts, such as gaps in parts, small circular arc angles, and transition areas with different shapes. On the other hand, it means that the working conditions and overload conditions of the parts are underestimated and the actual working capacity of the parts is insufficient, resulting in early failure of the parts.
2.Unreasonable material selection: In the design, the failure of the part is judged to be inaccurate, and the selected material properties cannot meet the working conditions; the performance index based on which the material is selected cannot reflect the resistance of the material to the actual failure mode, and the wrong material is selected; Poor material quality, unsatisfactory composition or performance, failure to meet design requirements, etc., are unreasonable.
3. Unreasonable processing technology: improper processing of the parts may cause various defects, leading to earlier failure of the parts during use. For example, overheating, overheating, and banding occur during thermal processing; decarburization, deformation, and cracking occur during heat treatment; deeper tool marks, grinding cracks, etc. occur during cold working.
4. Improper installation, assembly and installation process does not meet the technical requirements, such as matching too tight, too loose when installation, on, fixed instability can lead to such as parts can't work normally or premature failure;In addition, the use of illegal operation, overloading, overspeed, not timely maintenance and maintenance will also cause the premature failure of parts.