Due to the influence of factors such as processing, assembly and adjustment of new machine parts, the friction surface is rough, the contact area of the mating surface is small, and the pressure bearing condition of the surface is uneven. During the operation of the machine, the concave and convex parts on the surface of the parts fit and rub against each other, and the metal chips that fall off continue to participate in the friction as abrasives, which accelerates the wear of the mating surfaces of the parts. Therefore, it is easy to cause wear of parts (especially the mating surfaces) during the running-in period, and the wear rate is fast. At this time, if overloaded, it may cause damage to components and cause early failure.
Poor lubrication Because the fitting clearance of the newly assembled parts is small, and due to assembly and other reasons, it is difficult to ensure the uniformity of the fitting clearance, and the lubricating oil (grease) is not easy to form a uniform oil film on the friction surface to prevent wear. As a result, the lubrication efficiency is reduced and the early abnormal wear of the parts is caused. In severe cases, the friction surface of the precision fit will be scratched or occluded, resulting in failure.
The newly machined and assembled parts are loosened, and there are deviations in geometry and matching dimensions. In the early stage of use, due to alternating loads such as shock and vibration, as well as the influence of factors such as heat and deformation, as well as excessive wear and other reasons, it is easy to Loosen the previously tightened parts.
Leakage occurs due to the loosening of parts, vibration and the influence of heat on the machine, leakage will occur on the sealing surface of the machine and pipe joints, and some defects such as casting and machining are difficult to find during assembly and debugging, but due to the operation process. Vibration and impact, this defect is exposed, manifested as leakage (seepage) oil (water), therefore, leakage is prone to occur during the running-in period.
Operation errors are mostly due to insufficient understanding of the structure and performance of the machine (especially new operators), and it is easy to cause failures or even mechanical accidents due to operational errors.
