Research On The Cutting Force Modeling During Micro-end Milling Nickel-based Superalloy Processing

With the development of science and technology, the demand of micro parts and components for the fields of aerospace, biomedical, energy and power with high strength and corrosion resistance under high temperature circumstance is continuously increasing. The micro-milling technology based on micro milling machine, which is a novel processing technology for machining high precision miniature components with complex three-dimensional morphology, has become the research focus and hotspot for the field of micro machining in recent years. With excellent high temperature strength, good thermal stability and thermal fatigue resistance, the nickel-base superalloy can well satisfy the material requirements of micro parts and components with high strength and corrosion resistance under high temperature environment. Therefore, the research on micro milling mechanism and processing technology of nickel-base superalloy has important practical value to the enhancement of the ability and level of manufacturing micro high-temperature parts and components, and reference value to the research on the micro milling mechanism of difficult-to-machine materials.In this paper, a three-dimensional dynamic cutting force prediction model during micro-end milling nickel-base superalloy processing is established, considering the influences of trochoidal trajectory of the cutting-edge, radial run-out of cutting-edge, elastic recovery of processed surface, and so on, furthermore micro-end milling nickel-base superalloy processing experiments are carried out, and the influence principle of cutting parameters on cutting forces is analyzed, and the micro cutting force prediction model during micro-end milling nickel-base superalloy processing is established according to experiment results. This paper mainly includes the following:First of all, micro-milling hole experiments are carried out to research on the influence principle of extended length of cutter and spindle speed on the radial run-out of cutting-edge. And the radical run-out prediction model of cutting-edge is established according to experiment results, which lays the foundation for establishing the cutting thickness calculation model during micro-end milling.Secondly, the nominal cutting thickness calculation model during micro-end milling is established, with the consideration of the influence of trochoidal trajectory and radial run-out of cutting-edge. In addition the cumulative cutting thickness calculation model during actual cutting process is inferred, with the consideration of effects of single tooth cutting phenomenon and minimum cutting thickness phenomenon during micro-end milling process, which lays the foundation for establishing the three-dimensional dynamic cutting force prediction model.Thirdly, based on the minimum cutting thickness value. micro-end milling nickel-base superalloy process is divided into two different cutting processes:shear-dominant regime cutting process and ploughing-dominant regime cutting process. Moreover, cutting force prediction model during shear-dominant regime cutting process is developed based on the cutting force in proportion to cutting layer area, which takes the effect of ploughing into account. Meanwhile, cutting force prediction model during ploughing-dominant regime cutting process is developed based on the cutting force in proportion to interference volume between the flank surface of cutting tool and the workpiece. The experiment results verify that the cutting forces prediction results and experiment results are well matched.Finally, orthogonal experiments of micro-end milling nickel-base superalloy are carried out to research on the influence principle of cutting parameters on the cutting forces. And the three-dimensional cutting force prediction model during micro-end milling nickel-base superalloy processing is established according to experiment results. Moreover the significance test and fitting degree test are conducted on the prediction model.