The Study On Processes And Properties Of Laser Powder Feeding Additive And Milling Subtractive Hybrid Manufacturing For 316L Stainless Steel

Additive-subtractive hybrid manufacturing(ASHM),which combines the advantages of the high efficiency and high degree of freedom of additive manufacturing and the high precision and high surface quality of subtractive manufacturing,can solve the problems of low surface quality,low forming accuracy and high stress of additive formed parts,and can realize the direct manufacturing and re-repair manufacturing of parts in the aerospace,mold and other fields.Additive-subtractive hybrid manufacturing provides a new ideas for the manufacturing industry and has huge development potential and application prospects.However,there is little progress in the research on the process of additive-subtractive hybrid manufacturing,especially the related research on the synergistic processing of additive and subtractive at present.In view of the above research background,this paper studied the processes and properties of additivesubtractive hybrid manufacturing by building an integrated forming equipment for laser powder feeding additive and milling subtractive.The main research contents and conclusions are as follows:First,the laser directed energy deposition system was built on a CNC machine tool,so that the CNC machine tool has two processing methods: laser additive manufacturing and milling subtractive processing.At the same time,the coordinate system of additive manufacturing and the coordinate system of subtractive machining were coordinated.Then,according to the two main evaluation criteria of forming accuracy and surface quality,an experimental study of additive-subtractive hybrid manufacturing is carried out.In terms of forming accuracy,the influence of additive forming process on subtractive processing and subtractive processing on additive forming is discussed.The results show that the greater the arc of the edge collapse of the additive forming,the greater the milling depth;the increase in the number of milling will result in a decrease in the height of the additive forming;under different milling conditions,the amount of milling removal increases first and then remains with the increase in the number of milling.In terms of surface quality,the effects of milling parameters and additive forming temperature on surface roughness were studied and compared with traditional machining samples.The results show that as the milling speed increases,the surface roughness decreases;as the feed per tooth increases,the surface roughness increases;the surface roughness of the substrate sample is even higher than that of the sample manufactured by additive-subtractive hybrid manufacturing,and with the increase of the feed per tooth,the surface roughness of the substrate sample has a higher tendency to increase than that of the sample manufactured by additive-subtractive hybrid manufacturing;as the forming temperature decreases,the surface roughness decreases and the surface hardness increases.Finally,the forming characteristics of the 316 L stainless steel samples manufactured by additive manufacturing and additive-subtractive hybrid manufacturing were compared.The results show that the additive-subtractive hybrid manufacturing can not effectively increase the density of the sample by additive manufacturing;the improvement of the microhardness of the sample is only on the surface of the sample,but it has no effect on the internal hardness of the sample;the tensile properties of the sample have a certain improvement.At the same time,the preparation of tire mold samples for additive-subtractive hybrid manufacturing was carried out to verify the processing feasibility of the additive-subtractive hybrid manufacturing system.