Analysis For Mapping Relationship Between CNC Dynamic Performance And “s” Shape Specimen Processing Pricision

With the rapid development of the manufacturing industry, CNC machining precision also requires to be improved. As one of the main factors affecting the machining accuracy, dynamic characteristics of CNC machine tools has always been a major subject of research and discussion for scholars. "S" shaped test specimen as a new test specimen proposed by Chengdu Aircraft Industrial(Group) Co. Ltd, because of its unique design, with different geometric characteristics, it can better reflect the CNC machine processing accuracy. To establish an effective mapping between the "S" shaped test specimens and CNC machine tool dynamic characteristics could expand and enhance the value and scope of application of "S" shaped test specimen. This paper focuses on the research of mapping between the dynamic characteristics of CNC machine tools and "S" shaped test specimens machining accuracy. The main contents are as follows:1.Based on PID control theory, the translation axis and rotation axis of the feed system model has been constructed, and the dynamic performance of them have been adjusted and optimized, the dynamic stiffness of them have been analyzed. Using multi-body dynamics theory established a common 5-axis CNC machine tool simulation model, which can effectively carry out the processing error simulation. It makes a good foundation for the research of the mapping between dynamic characters of CNC machine tool and "S" shaped test specimens machining precision.2.The effects of the curvature and open-close angle on dynamic processing error have been analyzed. Through the theoretical research with combination of graphical and formula analysis, we get the conclusion that how dose the dynamic characters of CNC machine tool influence the processing error.3.Through the simulation model, by changing the dynamic characteristics of different axis, we could get the change of "S" shaped test specimens machining error compared with the CNC machine tool initial state. According to the typical geometric characteristics, we divide "S" shaped test specimens into some reasonable parts. Then through the color graph and line graph for the expression of error, we found the significant parts for the effects of different dynamic characteristics of CNC machine tool on the change of "S" shaped test specimens machining error. Thereby we could get the relationship between different dynamic characteristics of CNC machine tools and "S" shaped test specimens machining error.4.By making the rational design of orthogonal experiment, we carried out the actual cutting of "S" shaped test specimen. The simulation results were effective verification and also determined the validity of the conclusions.