Research On Machining Performance Of Internally Cooled High-pressure Cooling Tool Based On The 304 Stainless Steel

Because of excellent physical and chemical properties,difficult-to-machine materials such as 304 stainless steel have been widely used in industrial production.But the difficult-to-machine characteristics of these materials have always been the difficulties in processing and manufacturing,which are mainly manifested in the high cutting temperature,the large cutting force on the tool nose,the groove wear easily occurs under high temperature and pressure;the built-up edge is easily bonded to the cutting edge and easily trigger extrusion and recutting effect of chip;the chip are not easy to break,and continuous chip tangles workpieces and tools thus endanger production.These characteristics greatly reduce the cutting performance of tools,seriously affect the production efficiency and restrict the development of automated manufacturing.In this study,based on the analysis of many cooling and lubrication technologies and chip breaking technologies in the cutting process,a new type of internally cooled high-pressure cooling tool is designed according to the difficultto-machine characteristics of these materials.The new structure of turning tool makes the high-pressure cooling lubricant pass through the tool body and eject from a small hole on the rake face near the tool nose,and directly sprayed to the bottom of the new chip,which can cool and lubricate the cutting area,thrust the interminable chip,improve the cutting condition.In addition,a high-pressure cooling system is designed and manufactured by ourselves,The cutting performance of the internally cooled high-pressure cooling tool is discussed and analyzed theoretically and experimentally.Firstly,the strength check and comprehensive performance analysis of the new type of internally cooled high-pressure cooling tool are carried out.The simulation result of COMSOL Multiphysics indicates that the highest temperature in the cutting zone of the newly designed turning tool is greatly reduced under the condition of satisfying the stress and strength requirement,which can improve the tool durability and cutting condition to a certain extent,and confirm the feasibility of internally cooled high-pressure cooling technology.Secondly,the cooling and lubrication characteristics of high-pressure coolant,as well as the action mechanism and chip breaking mechanism of internally cooled high-pressure coolant are analyzed and studied.In the cutting process,the injected high-pressure coolant of new type tool can maximally carry off the heat from the tool-chip-workpiece system,making the cooling more efficient,it can also improve cutting condition through changing lubricated friction condition,moreover,high-pressure jet can force the chip to curl and break,and strongly control the formation of chip.Thirdly,the cutting temperature,cutting force and chip shape in the process of high-pressure coolant assisted cutting are simulated and analyzed by using the two-dimensional turning module of the professional metal cutting simulation software AdvantEdge.The simulation results show that,compared with dry cutting,the cutting edge temperature decreases by about 35%;and the chip tend to curl and break,showing great cooling effect and chip breaking trend.Finally,the cutting experiments of 304 stainless steel are carried out with the new type of internally cooled high-pressure cooling tool,the variation law of chip morphology and surface roughness under different cooling conditions and cutting parameters are discussed.The cutting results show that the high-pressure coolant can affect the curling and breaking of the chip,significantly reduce the curling radius of the chip,and obtain easily processed chip;at the same time,the highpressure coolant can improve the surface quality of the workpiece to a certain extent.