Deflection Prediction And Control In Milling Of Thin-Wall Titanium Alloy Components

Due to higher strength, higher heat resistance and higher corrosion resistance, titanium alloys are used in aerospace industry extensively. The machining deflection is one of the most tough problems in machining of the titanium alloy thin-wall parts. In the machining process of milling titanium alloy thin-wall parts, cutting force induced "part deflection", dynamic vibration of milling and residual stress redistribution are the most important factors which influence the machining precision and quality. In this thesis, by means of the theoretical modeling, finite element simulation and experiments verification, researches were conducted in cutting force modelling, machining stability, part deflection, prediction model and deflection control of the titanium alloy thin-wall milling.Finite element simulation model of milling force was established to investigate the milling process of titanium alloy, and predict milling force. Then experiments were designed to validate the reliability of simulation model.Based on the dynamic cutting force model, a method for obtaining the stability lobes was developed. The change of the modal parameters was analyzed by the finite element software in the milling process, and their influences on the stability lobes were analyzed by Matlab software.The milling test was used to research the T-shape and L-shape thin-wall components deflection. "Part deflection" in the machining processes and deflection after the machined were compared, and effect of cutting speed on the T-shape components deflection was researched by experiments. The finite element simulation was used to analyze the change in components stiffness, and its effect on deflection was analyzed.Mesh node renumbering, dynamic milling load enforcement and material removal key technique in the finite element simulation were used to predict "part deflection" in the milling process, and experiments were designed to investigate the reliability of simulation model. Based the secondary development technology of ABAQUS, the T-shape and L-shape milling deflection prediction platform were developed. Finally, based on the mirror tool compensation method, tool path was compensated and milling deflection in the milling process was reduced.