Crankshaft is one of the key parts of engine. It has complex structure, large production batch, frequent variety replacement and high precision requirement. The dimension accuracy of spindle connecting rod neck is IT6~IT7, roundness is less than 0.005mm, and surface roughness is Ra0.2~0.4. Therefore, an advanced crankshaft production line not only realizes flexible production change to meet market demand, but also meets technological requirements, guarantees processing accuracy, and finally produces qualified products. Forged steel crankshaft production line has the world's top CNC machine tools, advanced processing technology and increasingly perfect management system. It not only greatly improves the crankshaft processing efficiency, achieves flexible and rapid production capacity, but also better guarantees the crankshaft processing quality. At present, the quality of crankshaft is mainly guaranteed by the process control of machining and heat treatment. There are roughly three ways to ensure the quality of crankshaft:

1. Man-made inspection: refers to on-line measurement of each process according to process requirements by professional quality inspectors (or operators'self-inspection and mutual inspection), timely adjustment of process parameters, and avoidance of turnover of substandard products to the next process or mass rejection.

2. Equipment control: Relying on higher equipment accuracy to ensure the processing accuracy of the current process, is an effective way to ensure dimensional accuracy, shape accuracy and position accuracy, and is also one of the symbols of advanced crankshaft processing production line.

3. Process guarantee: Process is the law that converts crankshaft blank into finished product in the process of machining, and the criterion is the fundamental guarantee of product quality and the premise of improving processing efficiency.