The manufacturing of agricultural tractor engines is a complex process, from the casting, processing, assembly, painting of parts to the testing operations of the entire machine, some mechanical impurities will remain after each process is completed. If the cutting chips remaining on the positioning surfaces of the parts and fixtures are not removed during the processing of the agricultural tractor, the precise positioning of the parts will be affected. The chips remaining on the mating surface of the parts or in the oil passage holes are not cleaned up. In the assembly process, the surface of the precision parts will be scratched. During the trial operation and actual use, the mating surface is easy to cause damage; in addition, if the casting impurities in the unprocessed cavity (such as water channel or oil channel) and Too much sand will also affect the performance of the whole machine.

(1) For some moving parts of agricultural tractors, such as meshing gears, the surface roughness of the gears is also different due to the difference in processing technology and materials, which can easily cause steel chips to fall and form mechanical impurities.

(2) Immerse the casting sand, wear particles and flaking debris attached to the surface of the parts into the engine oil and fall off, enter the lubricating oil or gearbox oil, and contaminate the engine oil.

(3) Impurities remaining during maintenance, such as residues in the oil passage when grinding the crankshaft, and emery left after grinding the valve, are brought in due to careless cleaning.

(4) During the running-in period of the agricultural tractor, due to the use of dirty or polluted lubricating oil containing some impurities, the surface of the parts taken during the running-in period played a role in grinding.