Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of...Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of them.Dry cutting,a sustainable machining method,causes more friction and adhesion at the tool-chip interface.One of the promising solutions to this problem is cutting tool surface texturing,which can reduce tool wear and friction in dry cutting and improve machining performance.This paper aims to investigate the impact of dimple textures(made on the flank face of cutting inserts)on tool wear and chip morphology in the dry machining of AZ31B magnesium alloy.The results show that the cutting speed was the most significant factor affecting tool flank wear,followed by feed rate and cutting depth.The tool wear mechanism was examined using scanning electron microscope(SEM)images and energy dispersive X-ray spectroscopy(EDS)analysis reports,which showed that at low cutting speed,the main wear mechanism was abrasion,while at high speed,it was adhesion.The chips are discontinuous at low cutting speeds,while continuous at high cutting speeds.The dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.展开更多
The tool flank begins to wear out as soon as cutting process proceeds. Cutting parameters such as cutting forces and cutting temperature will vary with increasing degree of flank wear. In order to reveal the relations...The tool flank begins to wear out as soon as cutting process proceeds. Cutting parameters such as cutting forces and cutting temperature will vary with increasing degree of flank wear. In order to reveal the relationship between them, the theoretical situations of cutting process were analyzed considering the tool flank wear effect. The variation rules of cutting force, residual stress and temperature distributions along with the tool flank wear were analyzed comparing with the sharp tool tip. Through FEM simulation method, affections of the tool flank wear value VB on cutting forces, residual stress and temperature distributions were analyzed. A special result in this simulation is that the thrust force is more sensitive to tool flank wear, which can be used as a recognition method of tool condition monitoring. The FEM simulation analysis result agrees well with the experimental measuring data in public literatures and some experiments made also by the authors.展开更多
Short tool life and rapid tool wear in micromachining of hard-to-machine materials remain a barrier to the process being economically viable. In this study, standard procedures and conditions set by the ISO for tool l...Short tool life and rapid tool wear in micromachining of hard-to-machine materials remain a barrier to the process being economically viable. In this study, standard procedures and conditions set by the ISO for tool life testing in milling were used to analyze the wear of tungsten carbide micro-end-milling tools through slot milling conducted on titanium alloy Ti-6 Al-4 V. Tool wear was characterized by flank wear rate,cutting-edge radius change, and tool volumetric change. The effect of machining parameters, such as cutting speed and feedrate, on tool wear was investigated with reference to surface roughness and geometric accuracy of the finished workpiece. Experimental data indicate different modes of tool wear throughout machining, where nonuniform flank wear and abrasive wear are the dominant wear modes. High cutting speed and low feedrate can reduce the tool wear rate and improve the tool life during micromachining.However, the low feedrate enhances the plowing effect on the cutting zone, resulting in reduced surface quality and leading to burr formation and premature tool failure. This study concludes with a proposal of tool rejection criteria for micro-milling of Ti-6 Al-4 V.展开更多
The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of w...The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of wear zone of each end mill were analyzed, and three tool wear criterions of small-diameter end mills were defined. With the uEye camera, macro lens and 3-axis micro milling machine, it was proved the feasibility of measuring flank wear with the milling tests on a 45# steel workpiece. The design of experiment （DOE） showed that Vc was the most remarkable effect factor for the flank wear of small-diameter end mill. The wear curve of the experiments of milling was very similar to the Taylor curve.展开更多
The influence of hydrogen contents on the tool wear has been mainly focused on the flank wear of the common tool,and the influence of hydrogen contents on the rake crater wear（main wear type） of the tool,particularl...The influence of hydrogen contents on the tool wear has been mainly focused on the flank wear of the common tool,and the influence of hydrogen contents on the rake crater wear（main wear type） of the tool,particularly for the fine granular material tool,has been less investigated comprehensively.In this paper,for the purpose of researching the influence of hydrogen contents on tool wear,the titanium alloy Ti-6Al-4V is hydrogenated at 800 ℃ by thermohydrogen treatment technology and the turning experiments are carried out by applying uncoated WC-Co cemented carbide tool.The three-dimensional video microscope is used to take photos and measure tool wear.The results show that both of crater wear depth（KT） and average flank wear width（VB） firstly decreases and then increases with the increasing of hydrogen content.The maximum reducing amplitude of KT and VB is about 50% and 55%,respectively.Under the given conditions,the optimum hydrogen content is 0.26%.It is considered that the reduction of cutting temperature is an important factor for improving tool wear after the Ti-6Al-4V alloy is properly hydrogenated.Furthermore,the reasons of hydrogen effect on the tool wear are chiefly attributed to comprehensive effect of hydrogen contents on microstructure,physical properties and dynamic mechanical properties of the Ti-6Al-4V alloy.The proposed research provides the basic data for evaluating the machinability of hydrogenation Ti-6Al-4V alloy,and promotes practical application of thermohydrogen treatment technology in titanium alloys.展开更多
In order to decrease cutting fluid and improve environment, the cutting fluid was replaced by solid lubricant. Four kinds of solid lubricants were tested on a high temperature friction tester, from which nano K 2Ti ...In order to decrease cutting fluid and improve environment, the cutting fluid was replaced by solid lubricant. Four kinds of solid lubricants were tested on a high temperature friction tester, from which nano K 2Ti 4O 9 whisker enhanced solid lubrication film was chosen. It was coated on the surface of cutters and tested on a CA6140 lathe. At the rate of 400r/min, the wear of the tool flank with solid lubrication film is 1/6 of that without the film, and it is even lower than that using cutting fluid. With the increase of cutting speed, the wear of the tool flank with solid lubrication film is still lower than that without film, but it is higher than that using cutting fluid. Surface analyses by AFM, SEM and EDX reveal that the solid lubrication film can prevent Fe element of chips from diffusing the cutter surface; adhesion of the cutter and chips is abated and the wear of the tool flank is obviously decreased.展开更多
The present work aims at the microstructural characterization of TiAlZrN/ Al2O3 and TiAlZrN/Si3N4 coatings deposited via lateral rotating cathodes. The coatings were deposited using Lateral Rotating Cathodes (LARC) te...The present work aims at the microstructural characterization of TiAlZrN/ Al2O3 and TiAlZrN/Si3N4 coatings deposited via lateral rotating cathodes. The coatings were deposited using Lateral Rotating Cathodes (LARC) technology. The deposited coatings were studied for its cross sectional morphology using scanning electron microscopy. Energy Dispersive Spectrometry was also conducted along the cross section to determine the elemental composition. Micro Vickers hardness test was conducted to determine the hardness of the coatings. The scanning electron microscope images showed that TiAlZrN/Al2O3 coatings showed preferred columnar grain orientation with multilayered structure while TiAlZrN/Si3N4 coatings exhibit a dense grain structure. The TiAlZrN/Si3N4 coating shows a hardness of 31.58 GPa while TiAlZrN/Al2O3 coating shows a hardness of 25.40 GPa. Dry turning tests were performed on AISI 304 stainless steel. The TiAlZrN/Si3N4 coatings show reduced flank wear. Both the coatings even under severe cutting conditions impart surface roughness of less than 1.5 μm.展开更多
文摘Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of them.Dry cutting,a sustainable machining method,causes more friction and adhesion at the tool-chip interface.One of the promising solutions to this problem is cutting tool surface texturing,which can reduce tool wear and friction in dry cutting and improve machining performance.This paper aims to investigate the impact of dimple textures(made on the flank face of cutting inserts)on tool wear and chip morphology in the dry machining of AZ31B magnesium alloy.The results show that the cutting speed was the most significant factor affecting tool flank wear,followed by feed rate and cutting depth.The tool wear mechanism was examined using scanning electron microscope(SEM)images and energy dispersive X-ray spectroscopy(EDS)analysis reports,which showed that at low cutting speed,the main wear mechanism was abrasion,while at high speed,it was adhesion.The chips are discontinuous at low cutting speeds,while continuous at high cutting speeds.The dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.
基金Project(50435020) supported by the National Natural Science Foundation of China
文摘The tool flank begins to wear out as soon as cutting process proceeds. Cutting parameters such as cutting forces and cutting temperature will vary with increasing degree of flank wear. In order to reveal the relationship between them, the theoretical situations of cutting process were analyzed considering the tool flank wear effect. The variation rules of cutting force, residual stress and temperature distributions along with the tool flank wear were analyzed comparing with the sharp tool tip. Through FEM simulation method, affections of the tool flank wear value VB on cutting forces, residual stress and temperature distributions were analyzed. A special result in this simulation is that the thrust force is more sensitive to tool flank wear, which can be used as a recognition method of tool condition monitoring. The FEM simulation analysis result agrees well with the experimental measuring data in public literatures and some experiments made also by the authors.
基金the Engineering and Physical Sciences Research Council (EP/M020657/1) for the support for this work
文摘Short tool life and rapid tool wear in micromachining of hard-to-machine materials remain a barrier to the process being economically viable. In this study, standard procedures and conditions set by the ISO for tool life testing in milling were used to analyze the wear of tungsten carbide micro-end-milling tools through slot milling conducted on titanium alloy Ti-6 Al-4 V. Tool wear was characterized by flank wear rate,cutting-edge radius change, and tool volumetric change. The effect of machining parameters, such as cutting speed and feedrate, on tool wear was investigated with reference to surface roughness and geometric accuracy of the finished workpiece. Experimental data indicate different modes of tool wear throughout machining, where nonuniform flank wear and abrasive wear are the dominant wear modes. High cutting speed and low feedrate can reduce the tool wear rate and improve the tool life during micromachining.However, the low feedrate enhances the plowing effect on the cutting zone, resulting in reduced surface quality and leading to burr formation and premature tool failure. This study concludes with a proposal of tool rejection criteria for micro-milling of Ti-6 Al-4 V.
基金Supported by the Ministerial Level Advanced Research Foundation(51318020309)
文摘The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of wear zone of each end mill were analyzed, and three tool wear criterions of small-diameter end mills were defined. With the uEye camera, macro lens and 3-axis micro milling machine, it was proved the feasibility of measuring flank wear with the milling tests on a 45# steel workpiece. The design of experiment （DOE） showed that Vc was the most remarkable effect factor for the flank wear of small-diameter end mill. The wear curve of the experiments of milling was very similar to the Taylor curve.
基金Supported by the National Natural Science Foundation of China（No.50875068）,and the National High Technology Research and Development Programme of China（No.2009AA044302）.
基金supported by National Natural Science Foundation of China (Grant No. 50775115)
文摘The influence of hydrogen contents on the tool wear has been mainly focused on the flank wear of the common tool,and the influence of hydrogen contents on the rake crater wear（main wear type） of the tool,particularly for the fine granular material tool,has been less investigated comprehensively.In this paper,for the purpose of researching the influence of hydrogen contents on tool wear,the titanium alloy Ti-6Al-4V is hydrogenated at 800 ℃ by thermohydrogen treatment technology and the turning experiments are carried out by applying uncoated WC-Co cemented carbide tool.The three-dimensional video microscope is used to take photos and measure tool wear.The results show that both of crater wear depth（KT） and average flank wear width（VB） firstly decreases and then increases with the increasing of hydrogen content.The maximum reducing amplitude of KT and VB is about 50% and 55%,respectively.Under the given conditions,the optimum hydrogen content is 0.26%.It is considered that the reduction of cutting temperature is an important factor for improving tool wear after the Ti-6Al-4V alloy is properly hydrogenated.Furthermore,the reasons of hydrogen effect on the tool wear are chiefly attributed to comprehensive effect of hydrogen contents on microstructure,physical properties and dynamic mechanical properties of the Ti-6Al-4V alloy.The proposed research provides the basic data for evaluating the machinability of hydrogenation Ti-6Al-4V alloy,and promotes practical application of thermohydrogen treatment technology in titanium alloys.
文摘In order to decrease cutting fluid and improve environment, the cutting fluid was replaced by solid lubricant. Four kinds of solid lubricants were tested on a high temperature friction tester, from which nano K 2Ti 4O 9 whisker enhanced solid lubrication film was chosen. It was coated on the surface of cutters and tested on a CA6140 lathe. At the rate of 400r/min, the wear of the tool flank with solid lubrication film is 1/6 of that without the film, and it is even lower than that using cutting fluid. With the increase of cutting speed, the wear of the tool flank with solid lubrication film is still lower than that without film, but it is higher than that using cutting fluid. Surface analyses by AFM, SEM and EDX reveal that the solid lubrication film can prevent Fe element of chips from diffusing the cutter surface; adhesion of the cutter and chips is abated and the wear of the tool flank is obviously decreased.
文摘The present work aims at the microstructural characterization of TiAlZrN/ Al2O3 and TiAlZrN/Si3N4 coatings deposited via lateral rotating cathodes. The coatings were deposited using Lateral Rotating Cathodes (LARC) technology. The deposited coatings were studied for its cross sectional morphology using scanning electron microscopy. Energy Dispersive Spectrometry was also conducted along the cross section to determine the elemental composition. Micro Vickers hardness test was conducted to determine the hardness of the coatings. The scanning electron microscope images showed that TiAlZrN/Al2O3 coatings showed preferred columnar grain orientation with multilayered structure while TiAlZrN/Si3N4 coatings exhibit a dense grain structure. The TiAlZrN/Si3N4 coating shows a hardness of 31.58 GPa while TiAlZrN/Al2O3 coating shows a hardness of 25.40 GPa. Dry turning tests were performed on AISI 304 stainless steel. The TiAlZrN/Si3N4 coatings show reduced flank wear. Both the coatings even under severe cutting conditions impart surface roughness of less than 1.5 μm.
