A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperat...A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperature is measured by the tool/workpiece natural thermocouple, while the temperature distribution on the workpiece surface and that of interior are measured by some standard thermocouples prearranged at proper positions. The system can be used to measure cutting temperature in the machining with the rotary cutting tools, such as vertical drill and end milling cutter. It is practically used for the research on high-speed milling with hardened steel.展开更多
In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inhere...In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intru- siveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.展开更多
Carbon fiber reinforced silicon carbide matrix(Cf/SiC)composites have the most potential application for high-temperature components of aerospace high-end equipment.However,high cutting temperature,rapid tool wear and...Carbon fiber reinforced silicon carbide matrix(Cf/SiC)composites have the most potential application for high-temperature components of aerospace high-end equipment.However,high cutting temperature,rapid tool wear and severe surface damages are the main problems in dry cutting Cf/SiC composites process.The feasibility study on cryogenic milling of Cf/SiC composites using liquid nitrogen as coolant is investigated.Influences of milling parameters and coolant on temperature,cutting force,surface quality and tool wear are investigated,which is compared with dry cutting.Experimental results reveal that the cutting temperature in cryogenic milling of Cf/SiC composites is reduced by about 40%—60%compared with dry cutting.The milling force increases gradually with the increase of spindle speed,feed rate,depth and width of milling in cryogenic milling process.In addition,the machined surface quality in cryogenic milling is superior to that in dry cutting process.Fiber fracture,matrix damage and fiber matrix debonding are main material removal mechanisms.Flank face wear is the main wear form of the polycrystalline diamond(PCD)end mills.The tool life is prolonged in the cryogenic milling process because the reduced temperature inhibits the softening of Co binder and phase transition of diamond in the PCD end mills.展开更多
As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with the...As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with theoretical analysis, this paper investigates the effect of cutting edge radius on the unit cutting force, the cutting component forces ratio Fy/Fz, as well as the roughness and surface properties of the work-piece. Experimental results show that the value of tool cutting edge arc ρ has a significant impact on elastic-plastic deformation of the cutting area, and its influence on the surface quality of processing and precision is greater than common cutting. The method of calculating the theoretical limits of the diamond tool cutting edge radius is feasible. The value of 0.0001 μm has some guiding significance for the developement of suitable cutting thickness to ensure the normal cutting.展开更多
文摘A computer aided measurement system is used to measure the cutting temperature directly in high-speed machining by natural thermocouples and standard thermocouples. In this system the tool/workpiece interface temperature is measured by the tool/workpiece natural thermocouple, while the temperature distribution on the workpiece surface and that of interior are measured by some standard thermocouples prearranged at proper positions. The system can be used to measure cutting temperature in the machining with the rotary cutting tools, such as vertical drill and end milling cutter. It is practically used for the research on high-speed milling with hardened steel.
基金Project (No. DEARS/CASR/R-01/2001/D-934 (30)) supported by Directorate of Advisory Extension and Research Services (DAERS), Committee for Advanced Studies & Research (CASR), BUET, Dhaka, Bangladesh
文摘In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intru- siveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.
基金the National Natural Science Foundation of China(Nos.51705249,51875285)the China Postdoctoral Science Foundation(No.2019M661823)+1 种基金the Aeronautical Science Foundation of China(No.2017ZE52047)the Defense Industrial Technology Development Program(No.JCKY2018605C018)。
文摘Carbon fiber reinforced silicon carbide matrix(Cf/SiC)composites have the most potential application for high-temperature components of aerospace high-end equipment.However,high cutting temperature,rapid tool wear and severe surface damages are the main problems in dry cutting Cf/SiC composites process.The feasibility study on cryogenic milling of Cf/SiC composites using liquid nitrogen as coolant is investigated.Influences of milling parameters and coolant on temperature,cutting force,surface quality and tool wear are investigated,which is compared with dry cutting.Experimental results reveal that the cutting temperature in cryogenic milling of Cf/SiC composites is reduced by about 40%—60%compared with dry cutting.The milling force increases gradually with the increase of spindle speed,feed rate,depth and width of milling in cryogenic milling process.In addition,the machined surface quality in cryogenic milling is superior to that in dry cutting process.Fiber fracture,matrix damage and fiber matrix debonding are main material removal mechanisms.Flank face wear is the main wear form of the polycrystalline diamond(PCD)end mills.The tool life is prolonged in the cryogenic milling process because the reduced temperature inhibits the softening of Co binder and phase transition of diamond in the PCD end mills.
文摘As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with theoretical analysis, this paper investigates the effect of cutting edge radius on the unit cutting force, the cutting component forces ratio Fy/Fz, as well as the roughness and surface properties of the work-piece. Experimental results show that the value of tool cutting edge arc ρ has a significant impact on elastic-plastic deformation of the cutting area, and its influence on the surface quality of processing and precision is greater than common cutting. The method of calculating the theoretical limits of the diamond tool cutting edge radius is feasible. The value of 0.0001 μm has some guiding significance for the developement of suitable cutting thickness to ensure the normal cutting.
