Surface integrity of a new damage-tolerant titanium alloy （TC21）, including surface roughness, microhardness and metallurgical structure is investigated when normal and high speed milling are used at different tool ...Surface integrity of a new damage-tolerant titanium alloy （TC21）, including surface roughness, microhardness and metallurgical structure is investigated when normal and high speed milling are used at different tool wear status. Results show that good surface integrity of TC21 can be obtained in high speed milling. In addition, even in acutely worn stages, there is no so-called serious hardening layer （or white layer） according to the studies on microhardness and metallurgical structure.展开更多
This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different...This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different statistical methods.Vegetable oil was preferred as cutting fluid,and Taguchi method was used in the preparation of the test pattern.After testing with the prepared test pattern,cutting performance in all parameters has been improved according to dry conditions thanks to the MQL system.The highest tool life was obtained by using cutting parameters of 7.5 m cutting length,100 m/min cutting speed,100 mL/h MQL flow rate and 0.1 mm/tooth feed rate.Optimum cutting parameters were determined according to the Taguchi analysis,and the obtained parameters were confirmed with the verification tests.In addition,the optimum test parameter was determined by applying the gray relational analysis method.After using ANOVA analysis according to the measured surface roughness and cutting force values,the most effective cutting parameter was observed to be the feed rate.In addition,the models for surface roughness and cutting force values were obtained with precisions of 99.63%and 99.68%,respectively.Effective wear mechanisms were found to be abrasion and adhesion.展开更多
This paper studies the influence of radial depth on vibration, chip formation and surface roughness during face milling of AISl3O4 austenitic stainless steel with indexable cemented carbide milling cutters. The amplit...This paper studies the influence of radial depth on vibration, chip formation and surface roughness during face milling of AISl3O4 austenitic stainless steel with indexable cemented carbide milling cutters. The amplitude of vibration acceleration increased with the increasing radial depth up to 80 mm. And the domain vibration frequency varied with the radial depth. In this paper, three types of chips were found： C shape, long shape and spiral shape. The minimum surface roughness value occurred when the radial depth equalled 40 mm in the experiment. Irregular changes of chip curl radius and chip thickness could be attributed to different numbers of alternately engaged teeth when the feed and speed were fixed. Surface roughness is related to forced vibration and chip formation. Radial depth with different numbers of alternately engaged teeth could significantly influence the forced vibration, chip formation, and surface roughness.展开更多
The milling machinabilities of titanium matrix composites were comprehensively evaluated to provide a theoretical basis for cutting parameter determination. Polycrystalline diamond （PCD） tools with different grain s...The milling machinabilities of titanium matrix composites were comprehensively evaluated to provide a theoretical basis for cutting parameter determination. Polycrystalline diamond （PCD） tools with different grain sizes and geometries, and carbide tools with and without coatings were used in the experiments. Milling forces, milling temperatures, tool lifetimes, tool wear, and machined surface integrities were investigated. The PCD tool required a primary cutting force 15 % smaller than that of the carbide tool, while the uncoated carbide tool required a primary cutting force 10% higher than that of the TiA1N-eoated tool. A cutting force of 300 N per millimeter of the cutting edge （300 N/mm） was measured. This caused excessive tool chipping. The cutting temperature of the PCD tool was 20%-30% lower than that of the carbide tool, while that of the TiA1N-coated tool was 12% lower than that of the uncoated carbide tool. The cutting temperatures produced when using water-based cooling and minimal quantity lubrication （MQL） were reduced by 100 ~C and 200 ~C, compared with those recorded with dry cutting, respectively. In general, the PCD tool lifetimes were 2--3 times longer than the carbide tool lifetimes. The roughness Ra of the machined surface was less than 0.6μm, and the depth of the machined surface hardened layer was in the range of 0.15-0.25 mm for all of the PCD tools before a flank wear land of 0.2 mm was reached. The PCD tool with a 0.8 mm tool nose radius, 0% rake angle, 10% flank angle, and grain size of （30＋2） μm exhibited the best cutting performance. For this specific tool, a lifetime of 16 rain can be expected.展开更多
基金Supported by the National Natural Science Foundation of China(50975141)the National Scienceand Technology Major Project(2010ZX04012-042)the Aeronautical Science Foundation(2010352005)~~
文摘Surface integrity of a new damage-tolerant titanium alloy （TC21）, including surface roughness, microhardness and metallurgical structure is investigated when normal and high speed milling are used at different tool wear status. Results show that good surface integrity of TC21 can be obtained in high speed milling. In addition, even in acutely worn stages, there is no so-called serious hardening layer （or white layer） according to the studies on microhardness and metallurgical structure.
文摘This study aims to examine the usability of environmentally harmless vegetable oil in the minimum quantity of lubrication(MQL)system in face milling of AISI O2 steel and to optimize the cutting parameters by different statistical methods.Vegetable oil was preferred as cutting fluid,and Taguchi method was used in the preparation of the test pattern.After testing with the prepared test pattern,cutting performance in all parameters has been improved according to dry conditions thanks to the MQL system.The highest tool life was obtained by using cutting parameters of 7.5 m cutting length,100 m/min cutting speed,100 mL/h MQL flow rate and 0.1 mm/tooth feed rate.Optimum cutting parameters were determined according to the Taguchi analysis,and the obtained parameters were confirmed with the verification tests.In addition,the optimum test parameter was determined by applying the gray relational analysis method.After using ANOVA analysis according to the measured surface roughness and cutting force values,the most effective cutting parameter was observed to be the feed rate.In addition,the models for surface roughness and cutting force values were obtained with precisions of 99.63%and 99.68%,respectively.Effective wear mechanisms were found to be abrasion and adhesion.
基金Supported by National Science and Technology Major Project of China(No.2009ZX04012-021)Major State Basic Research Development Program of China ("973" Program, No.2009CB724306)
文摘This paper studies the influence of radial depth on vibration, chip formation and surface roughness during face milling of AISl3O4 austenitic stainless steel with indexable cemented carbide milling cutters. The amplitude of vibration acceleration increased with the increasing radial depth up to 80 mm. And the domain vibration frequency varied with the radial depth. In this paper, three types of chips were found： C shape, long shape and spiral shape. The minimum surface roughness value occurred when the radial depth equalled 40 mm in the experiment. Irregular changes of chip curl radius and chip thickness could be attributed to different numbers of alternately engaged teeth when the feed and speed were fixed. Surface roughness is related to forced vibration and chip formation. Radial depth with different numbers of alternately engaged teeth could significantly influence the forced vibration, chip formation, and surface roughness.
基金supported by the National Natural Science Foundation of China(No.51275227)the Funding of Jiangsu Innovation Program for Graduate Education(No.CXLX11_0175)the Shanghai Aerospace Science and Technology Innovation Fund(No.SAST201326)
文摘The milling machinabilities of titanium matrix composites were comprehensively evaluated to provide a theoretical basis for cutting parameter determination. Polycrystalline diamond （PCD） tools with different grain sizes and geometries, and carbide tools with and without coatings were used in the experiments. Milling forces, milling temperatures, tool lifetimes, tool wear, and machined surface integrities were investigated. The PCD tool required a primary cutting force 15 % smaller than that of the carbide tool, while the uncoated carbide tool required a primary cutting force 10% higher than that of the TiA1N-eoated tool. A cutting force of 300 N per millimeter of the cutting edge （300 N/mm） was measured. This caused excessive tool chipping. The cutting temperature of the PCD tool was 20%-30% lower than that of the carbide tool, while that of the TiA1N-coated tool was 12% lower than that of the uncoated carbide tool. The cutting temperatures produced when using water-based cooling and minimal quantity lubrication （MQL） were reduced by 100 ~C and 200 ~C, compared with those recorded with dry cutting, respectively. In general, the PCD tool lifetimes were 2--3 times longer than the carbide tool lifetimes. The roughness Ra of the machined surface was less than 0.6μm, and the depth of the machined surface hardened layer was in the range of 0.15-0.25 mm for all of the PCD tools before a flank wear land of 0.2 mm was reached. The PCD tool with a 0.8 mm tool nose radius, 0% rake angle, 10% flank angle, and grain size of （30＋2） μm exhibited the best cutting performance. For this specific tool, a lifetime of 16 rain can be expected.
