With increasingly stringent automotive vehicle engine power, economic, environmental and reliability requirements, the piston has developed into a set of lightweight high strength of the new material, shaped cylindrical surface of the composite, profiled pin holes, and other multi-new technologies in one of the high-tech products, to ensure that the piston heat resistance, wear resistance, a smooth oriented and good sealing function, reduce engine friction power loss, lower fuel consumption, noise and emissions. In order to meet the above functional requirements, it is usually designed as the outer circumference of the piston shaped cylindrical (convex varying elliptical), i.e. a cross-sectional view perpendicular to the axis of the piston oval or correction elliptical and ovality in the axial direction changes according to certain rules (Figure 1), ovality accuracy of 0.005mm; piston outer contour of the longitudinal section of the fitting curve of the high function and contour accuracy of 0.005 ~ 0.01mm; order to improve the carrying capacity of the piston to improve engine l power, typically high load piston pin hole design within micro-cone or positive stress surfaces (shaped pin hole), the pin hole dimensional accuracy of IT4 level, contour accuracy of 0.003mm.
    Piston cutting as the typical automotive key components, has strong characteristics of the process. At present, the domestic piston manufacturing industry usually by the general machine combined piston technology characteristics of special equipment composed of machine processing production line, special equipment piston cutting machining of critical equipment, its function and accuracy will directly affect the final product of the key characteristics of quality indicators.