Study On Key Processes Of IN718 Alloy Additive And Subtractive Manufacturing Based On Thermogenetic Effect

Additive and subtractive integrated composite manufacturing technology is an important way to achieve high-precision forming of complex metal parts.This technology can realize the rapid switching of laser additive forming and subtractive machining processes while ensuring the machining accuracy of parts,and then realize the rapid manufacturing of complex metal parts.The substrate made by laser additive manufacturing is immediately switched to the subtractive processing process,and its own high temperature field will have a significant impact on the cutting performance.The energy input in the laser additive manufacturing process brings thermal genetic effect to the additive substrate.The change of the temperature of the substrate itself leads to the change of the material properties of the additive substrate,which ultimately affects the forming quality of the additive and subtractive integrated composite manufacturing parts.Therefore,in this thesis,the metal material IN718 alloy commonly used in aerospace field is taken as the research object,and the machinability of additive and subtractive integrated composite manufacturing based on thermogenetic effect is studied.The influence of thermogenetic temperature on the cutting performance and tool durability of additive manufacturing IN718 alloy is explored,and the related mechanism is revealed by cutting simulation.Firstly,the thermogenetic temperature law of laser additive manufacturing substrate is measured.The temperature of the additive substrate is measured by infrared thermal imager immediately after the addition of the substrate,and the data of the temperature of the additive substrate changing with time are recorded.Based on the measured thermogenetic temperature law,the experimental study on the processing of IN718 alloy milling cutting materials with different thermogenetic states was carried out.The additive substrate was milled under different thermogenetic states,three cutting speeds and three feed per tooth were set.Processing parameters,multi-group additive and subtractive integrated composite manufacturing IN718 alloy samples under different thermogenetic states and different milling parameters were prepared.Secondly,the effects of thermogenetic effect on the microstructure,surface quality,tool wear and chip morphology of additive IN718 alloy were analyzed.The surface roughness,surface hardness and internal microstructure of the sample were tested and observed,and the chip morphology and milling cutter wear degree were analyzed.The experimental results show that the thermogenetic temperature can improve the machinability of the additive substrate.Compared with the machining at room temperature,the machined surface of the specimen milled at 400 °C has better surface roughness.The milling cutter processed by high thermogenetic temperature condition has lower wear degree,but the improvement effect gradually weakens with the increase of cutting speed.At the same time,the thermogenetic temperature,cutting speed and feed per tooth will affect the chip size,color,thickness and serrated lamellar structure,and the effect of thermogenetic temperature is the most significant.Finally,the milling process of IN718 alloy additive substrate with thermogenetic effect is simulated by ABAQUS software.The results show that the thermogenetic temperature and the cutting speed will affect the temperature state of the cutting heat affected zone.At high thermogenetic temperature,the cutting heat affected zone shows a higher temperature state at high cutting speed.The feed per tooth will affect the area of the high temperature concentration area in the cutting heat affected zone.The high temperature state of the cutting position will cause changes in the properties of the substrate material.primarily,the thermal softening effect of the substrate material will reduce the cutting force during the cutting process and affect the residual stress distribution on the machined surface.The other hand,the temperature state will affect the grain morphology near the surface of the substrate processing surface,and then affect the formability of the processed surface.During the cutting process,thermogenetic temperature and cutting heat can also cause thermal softening effects on the tool matrix material,thereby affecting the degree of tool wear.