Studies On The CNC Prototype Machine Tool And Machining Process Of Carbon Fiber Reinforced Plastics Cylindrical Component

Carbon fiber reinforced plastics (CFRP) have been widely used in aerospace, defense and transportation applications because of their excellent mechanical properties such as high specific strength and high specific stiffness. However, it's easy to produce burr, delamination, splintering and other defects in drilling as its mechanical property is anisotropic. The defects produced in the secondary processing can not be repaired, which will cause significant economic losses.Carbon fiber reinforced composites are applied in rocket, spaceship to produce cylindrical component with a large size and thin wall. After molding of cylindrical component, it requires mechanical processing such as a large quantity of riveting and bolt holes as well as window. The quality of holes directly affects the assembly precision and performance property of the spacecraft. Aimed at this kind of cylindrical component, "manual processing" is applied at home. Due to its inefficiency, it has seriously hampered the progress of product development and mass production. Using electroplating superabrasive tools, the process of "Drilling replaced by grinding" can notably improve the processing quality and efficiency of carbon fiber reinforced composites. But now special-purpose numerically controlled machine tools for machining the cylindrical component using the process of "Drilling replaced by grinding" have not been developed yet, which possess high spindle speed between 5000r/min and 15000r/min.Through the analysis of the cylindrical component's structural characteristics and processing requirements, and the structural layout of several existing machine tools, overall layout of a single purpose machine called "Vertical rotary table with fixed cantilevered beam and mobility" was put forward in this thesis in order to solve the problems such as low efficiency and poor precision brought by traditional manual processing. Adopting fixed cantilever, it was easier to control the position accuracy when the cantilever moved backwards and forwards compared to the conventional ones. Based on the design proposal of fixed cantilever, critical components of the machine tool such as the base, the pillar and the cantilever beam were designed. Static structure analysis and modal analysis of the key parts of the prototype machine tool were done by ANSYS. The results showed that the stiffness fully met the design requirements with small deformations and strong antijamming ability. Using UG software, 3-D model of the cylindrical component was built and the processing path was programed. Post processor was structured to generate NC machining program that can be carried out in the special machine to machine cylindrical components. The prototype machine tool modal was established by VERICUT software. Based on the modal, the processes of machining the cylindrical component were simulated and the NC program was tested through virtual machining by VERICUT.This prototype machine tool can drill and grind the cylindrical component in a low-cost, high-precision and high efficiency way. It laid the foundation for finalizing the design of CNC Machine Tool for cylindrical component machining.