1. Fast wear speed
Due to the influence of 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 are fitted with each other for friction, and the metal debris that falls off from the grinding continues to participate in friction as abrasive, which further accelerates the wear of the fitting surface of the parts. Therefore, it is easy to cause the wear of parts (especially the mating surface) during the running in period, and the wear speed is fast. At this time, if overloaded operation, it may lead to damage of parts and early failure.
2. Poor lubrication
Since the fitting clearance of 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. Thereby reducing the lubrication efficiency and causing early abnormal wear of the machine parts. In serious cases, it will cause scratch or bite on the friction surface of the precision fitting, leading to failure.
3. Looseness
The newly processed and assembled parts have geometric shape and fitting dimension deviation. In the early stage of use, due to the impact, vibration and other alternating loads, as well as the influence of heating, deformation and other factors, as well as the rapid wear and other reasons, it is easy to make the original fastened parts loose.
4. Leakage
Due to the looseness and vibration of the machine parts and the influence of the heating of the machine, leakage may occur at the sealing surface of the machine and the pipe joint; Some defects such as casting and machining are difficult to find during assembly and commissioning. However, due to the vibration and impact during operation, such defects are exposed, which are manifested as oil (water) leakage. Therefore, leakage is easy to occur during the running in period.
5. Many operation errors
Due to insufficient understanding of the structure and performance of the machine (especially the new operator), it is easy to cause failures due to operation errors and even mechanical accidents.
