Design And Cooling Performance Of A Composite Cooling Tool Based On Internal Cooling And Spray Cooling

In traditional machining,in order to conduct cutting heat in a timely manner,thereby improving processing accuracy and prolonging the service life of tools,the method of pouring a large amount of cutting fluid is often used to cool down.Although the cutting fluid can reduce the cutting force of the tool and improve the surface quality of the workpiece,it is of great help to the processing and production.However,the large amount of cutting fluid will cause environmental pollution and endanger human health,which does not meet the needs of national sustainable development.In the common green cooling method,the circulating internal cooling tool can make the coolant circulate in the tool and be closer to the cutting zone,which can avoid the pollution of the coolant to the environment and achieve quickly transfers heat.However,the circulating internal cooling tool also have problems that the coolant cannot wash the chips,cannot cool the chips,and assist the chip removal.The spray cooling method can not only be cooled by the outside of the tool,but also can promote chip removal.For this reason,based on the ideas of improving cooling performance and assist chip removal,this paper designed a circulating internal cooling and spray composite cooling turning tool,and carried out experimental research on the cooling performance of the designed turning tools for aluminum alloy 6060.First,the advantages of the combined application of the internal cooling technology and the spray cooling technology are theoretically analyzed.From the angle of not affecting the normal operation and convenient installation of the tool,a reasonable layout of the internal cooling structure on the toolholder is designed.For the arrangement of the spray structure on the toolholder,two types of circulating internal cooling and spray composite cooling turning tool with single nozzle type and double nozzle type are designed,and the comparative simulation analysis of the tool cooling performance under different nozzle numbers is carried out.The influence of the number of nozzles on the cooling performance of the internal cooling and spray combined cooling turning tools was studied.Considering the cooling efficiency,lubrication effect and other aspects,the best design plan of the circulating internal cooling and spray composite cooling turning tool is selected to lay the foundation for the next research.Secondly,the combination of CFD simulation and Taguchi design is used to optimize the spray geometry of the circulating internal cooling and spray composite cooling turning tool.Four parameters of the distance between the two nozzles and the tip and two diameters of the nozzle outlet were selected as the structural optimization parameters,and the thermal-fluidsolid coupling analyses was carried out with the minimum weighted average temperature of the cutting zone as the target.The influence of each structural optimization parameter on the area weighted average temperature is analyzed.The optimized composite cooling turning tool solution is as follows: the upper nozzle outlet diameter is 3.0 mm,the lower nozzle outlet diameter is 3.0 mm,the distance between the upper spray outlet and the cutting tool tip is 21.0 mm,the distance between the lower spray outlet and the cutting tool tip is 14.6 mm.Then,three spray parameters,namely the spray pressure,the spray flow rate,the coolant temperature for spray cooling,were selected for CFD simulation,and the influence of different spray parameters on the cooling performance of the composite cooling tool was investigated.The effect of different parameters on the cutting temperature was obtained by a single factor test.Studies have shown that changes in spray pressure and coolant temperature for spray cooling can have a significant effect on reducing cutting temperatures,while spray flow rate has little effect on turning efficiency.The reason for this phenomenon is explained from the perspective of influencing the formation of the film.Finally,the machining experiment of circulating internal cooling and spray composite cooling turning tool for turning aluminum alloy 6061 is designed.The experimental parameters include cutting speed,Feed rate,cutting depth and other factors.Using the cutting temperature data collected in the turning test,the variation of cutting temperature during the cutting of the circulating internal cooling tool and the circulating internal cooling and spray composite cooling turning tool was compared and analyzed.Compared with the circulating internal cooling tool,the circulating internal cooling and spray composite cooling turning tool has better cooling performance.