Mechanical modeling of five-axis single root clean-up machining of complex surface

Abstract

Root clean-up machining is an important process for five-axis machining of complex curved surface parts. Subjected to harsh cutting conditions and lack of analysis of cutting force, single root clean-up machining cannot be used widely though it is a machining method with high efficiency and no residue. Whereupon, this paper establishes a single root clean-up machining mechanical model for five-axis ball-end milling of complex surface creatively. According to the characteristic of the ball-end mill, expression of differential element cutting force is optimized. Concave corner of a complex surface is discretized into a series of concave crescent cylinders (CCCs) along tool path. Aiming at five-axis single root clean-up machining of CCC, cutter axis and feed direction are defined parametrically. The analytical expressions of complex surface to-be-clean-up and allowance section plane are derived in cutter coordinate system to limit spatial conditions of cutter edge participating in cutting. In-cut cutting edge (ICCE) is defined by searching and judging the cutter edge elements one by one, and a one-dimensional binary search method is used to further improve the precision of boundary. Cutter run-out parameters are defined, and its effect on undeformed chip thickness is deduced. In conclusion, the mechanical model for single root clean-up machining of five-axis ball-end milling of CCC can be established which is applicable to complex surface. A series of experiments and simulations were arranged. The ICCE analytical algorithm based on the CCC has the same precision and higher efficiency compared with solid modeling method. Due to the influence of curvature of the two flank surfaces and the tool path, there will be a slight deviation when the ICCE applies to the complex surface. The predicted force of single root clean-up machining of complex surface agrees well with measured force, which validates the mechanical model.