Y9420 Gear Chamfering Machine is ahigh efficiency machine tool designedby the Chongqing Machine ToolsWorks to meet market demand. The machineemploys the principle of cool extrusion anduses a special chamfering tool wh...Y9420 Gear Chamfering Machine is ahigh efficiency machine tool designedby the Chongqing Machine ToolsWorks to meet market demand. The machineemploys the principle of cool extrusion anduses a special chamfering tool which drivesthe work piece to rotate and achievechamfering. It features no tool tracks and noburr on the ends. Multiple cutters can beused to process cluster gears, and thechamfering can be realized on either oneside of the tooth or on both. It is an idealpiece of equipment for automobiles, machinetools and gears manufacture to chamfer anddeburr disk type gears, spur and helical shaftgears and cluster gears.展开更多
In the multilayer film-substrate system,thermal stress concentration and stress mutations cause film buckling,delamination and cracking,leading to device failure.In this paper,we investigated a multilayer film system ...In the multilayer film-substrate system,thermal stress concentration and stress mutations cause film buckling,delamination and cracking,leading to device failure.In this paper,we investigated a multilayer film system composed of a substrate and three film layers.The thermal stress distribution inside the structure was calculated by the finite element method,revealing significant thermal stress differences between the layers.This is mainly due to the mismatch of the coefficient of thermal expansion between materials.Different materials respond differently to changes in external temperature,leading to compression between layers.There are obvious thermal stress concentration points at the corners of the base layer and the transition layer,which is due to the sudden change of the shape at the geometric section of the structure,resulting in a sudden increase in local stress.To address this issue,we chamfered the substrate and added an intermediate layer between the substrate and the transition layer to assess whether these modifications could reduce or eliminate the thermal stress concentration points and extend the service life of the multilayer structure.The results indicate that chamfering and adding the intermediate layer effectively reduce stress discontinuities and mitigate thermal stress concentration points,thereby improving interlayer bonding strength.展开更多
Owing to heavy dynamic and thermal loads, PCBN tools are seriously worn during hard cutting, which largely constrains the improvement of their machining performance. Therein, the chamfered structure of a cutting edge ...Owing to heavy dynamic and thermal loads, PCBN tools are seriously worn during hard cutting, which largely constrains the improvement of their machining performance. Therein, the chamfered structure of a cutting edge has a notable influence on the tool wear. Thus, a comparative study was carried out on the wear morphology and wear mechanism of PCBN tools with either a variable chamfered edge or an invariable chamfered edge. The results indicate that, for a PCBN tool with a variable chamfered edge, the rake wear area is far from the cutting edge and slowly extends toward it. A shallow large-area crater wear occurs on the rake face, and the flank wear area has a long triangular shape with a smaller wear area and width, and the cutting edge remains in a good state during the cutting process. In contrast, for a PCBN tool with an invariable chamfered edge, a deep small-area crater appears on the rake face, and the wear area is close to the cutting edge and quickly extends toward it. Thus, it is easy for chips to accumulate in the crater, resulting in large-area and high-speed wear on the flank face. In addition, the tool shows a weak wear resistance. In the initial wear stage, the rake wear mechanism of the two cutting tools is a mixture of abrasive, oxidation, and other types of wear, whereas their flank wear mechanism is dominated by abrasive wear. With an aggravation of the tool wear, the oxidation and diffusion wear mechanism are both increasingly strengthened. The rake wear of the cutter with a variable chamfered edge showed an obvious increase in the oxidation and diffusion wear, as did the flank wear of the cutter with an invariable chamfered edge. This study revealed the wear mechanism of the PCBN tool with a variable chamfered edge and provided theoretical and technological support for its popularization and application in the machining of high-hardness materials.展开更多
In order to analyze the influence of the hole chamfer on the metering performances of a Multi-hole Orifice Flowmeter and optimize the related orifice structure,a multi-hole orifice flowmeter with DN80 and throttle rat...In order to analyze the influence of the hole chamfer on the metering performances of a Multi-hole Orifice Flowmeter and optimize the related orifice structure,a multi-hole orifice flowmeter with DN80 and throttle ratio of 0.45 was considered in the present study.The flow field characteristics were determined in the framework of a CFD technique.The results show that the multi-hole orifice flowmeter with filleting transition around the throttle orifice has higher accuracy in a wide range of the space of parameters,and is more suitable for accurate measurement of fluid in process control.展开更多
We present a robust mesh sharpening approach to reconstructing sharp features from blended or chamfered features, even with noise and aliasing errors. Feature regions were first recognized via normal variation accordi...We present a robust mesh sharpening approach to reconstructing sharp features from blended or chamfered features, even with noise and aliasing errors. Feature regions were first recognized via normal variation according to the user's input, and then normal filtering was applied to faces of feature regions. Finally, the vertices of the feature region were gradually updated based on new face normals using a least-squares error criterion. Experimental results demonstrate that the method is effective and robust in sharpening meshes.展开更多
Eccentric compression tests on 15 chamfered laminated bamboo lumber(LBL)columns with a height ranging from 600 to 3000 mm were conducted in order to study the eccentric mechanical performance.The failure of all specim...Eccentric compression tests on 15 chamfered laminated bamboo lumber(LBL)columns with a height ranging from 600 to 3000 mm were conducted in order to study the eccentric mechanical performance.The failure of all specimens was caused by the crack of bamboo fiber in the tensile region.When the ultimate strength was reached,except specimens with a height of 600 mm,all other specimens could bear large deformation,showing good ductility.The lateral displacements of the specimens under eccentric compression were approximately para-bolic in the direction of column height.The ultimate bending moment of LBL columns with different slenderness ratios under compression with the same initial eccentricity was a fixed value.The relationship between ultimate capacity,axial displacement,lateral displacement,and slenderness ratio was analyzed based on test results.It was found that the plane section assumption could be used to express the stress and strain distribution of chamfered LBL columns under eccentric compression.A method for calculating the ultimate bearing capacity was proposed using a constitutive model based on the Ramberg-Osgood relation and the empirical formula for calculating the ultimate capacity was given on the basis of the former research as well as the test results in this paper.展开更多
Chamfered mould has gradually become a new technology equipment to eliminate transverse corner crack.However,longitudinal corner crack ratio of chamfered slab was very high.Solidification microstructure was detected i...Chamfered mould has gradually become a new technology equipment to eliminate transverse corner crack.However,longitudinal corner crack ratio of chamfered slab was very high.Solidification microstructure was detected in the area where the longitudinal corner crack occurred.Effect of narrow face shape and taper distribution of mould copper plate on longitudinal corner crack was studied by industrial tests.Water velocity distribution in the narrow copper plate was studied by numerical simulation.On the premise of preventing cooling water from nuclear boiling,improvement measures of mould cooling process and water seam structure were put forward through heat transfer calculation.The results showed that local taper of the meniscus region of mould should be increased to prevent generation of longitudinal corner crack.Chamfering slope length of narrow copper plate should be controlled within 55 mm,and chamfering angle should be controlled at about 30°.Average water velocity should be more than 7.0 m/s.The flat and chamfering regions of narrow copper plate working face should be designed as double taper and funnel structure,respectively.The water seam in the chamfering region should preferentially choose the combined cooling structure with two holes and one slot.In order to prevent the extension of longitudinal corner crack,chamfered narrow face foot roller should be used.展开更多
文摘Y9420 Gear Chamfering Machine is ahigh efficiency machine tool designedby the Chongqing Machine ToolsWorks to meet market demand. The machineemploys the principle of cool extrusion anduses a special chamfering tool which drivesthe work piece to rotate and achievechamfering. It features no tool tracks and noburr on the ends. Multiple cutters can beused to process cluster gears, and thechamfering can be realized on either oneside of the tooth or on both. It is an idealpiece of equipment for automobiles, machinetools and gears manufacture to chamfer anddeburr disk type gears, spur and helical shaftgears and cluster gears.
基金the support of the National Natural Science Foundation of China(Grant Nos.51606158,11604311 and 12074151)the Guangxi Science and Technology Base and Talent Special Project(Grant No.AD21075009)+2 种基金the Sichuan Science and Technology Program(Grant No.2021JDRC0022)the Open Fund of the Key Laboratory for Metallurgical Equipment and Control Technology of Ministry of Education in Wuhan University of Science and Technology,People's Republic of China(Grant Nos.MECOF2022B01 and MECOF2023B04)the Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology(Grant No.DH202321)。
文摘In the multilayer film-substrate system,thermal stress concentration and stress mutations cause film buckling,delamination and cracking,leading to device failure.In this paper,we investigated a multilayer film system composed of a substrate and three film layers.The thermal stress distribution inside the structure was calculated by the finite element method,revealing significant thermal stress differences between the layers.This is mainly due to the mismatch of the coefficient of thermal expansion between materials.Different materials respond differently to changes in external temperature,leading to compression between layers.There are obvious thermal stress concentration points at the corners of the base layer and the transition layer,which is due to the sudden change of the shape at the geometric section of the structure,resulting in a sudden increase in local stress.To address this issue,we chamfered the substrate and added an intermediate layer between the substrate and the transition layer to assess whether these modifications could reduce or eliminate the thermal stress concentration points and extend the service life of the multilayer structure.The results indicate that chamfering and adding the intermediate layer effectively reduce stress discontinuities and mitigate thermal stress concentration points,thereby improving interlayer bonding strength.
基金Supported by National Natural Science Foundation of China(Grant No.51475125)Heilongjiang Provincial Natural Science Foundation of China(Grant No.E2016047)
文摘Owing to heavy dynamic and thermal loads, PCBN tools are seriously worn during hard cutting, which largely constrains the improvement of their machining performance. Therein, the chamfered structure of a cutting edge has a notable influence on the tool wear. Thus, a comparative study was carried out on the wear morphology and wear mechanism of PCBN tools with either a variable chamfered edge or an invariable chamfered edge. The results indicate that, for a PCBN tool with a variable chamfered edge, the rake wear area is far from the cutting edge and slowly extends toward it. A shallow large-area crater wear occurs on the rake face, and the flank wear area has a long triangular shape with a smaller wear area and width, and the cutting edge remains in a good state during the cutting process. In contrast, for a PCBN tool with an invariable chamfered edge, a deep small-area crater appears on the rake face, and the wear area is close to the cutting edge and quickly extends toward it. Thus, it is easy for chips to accumulate in the crater, resulting in large-area and high-speed wear on the flank face. In addition, the tool shows a weak wear resistance. In the initial wear stage, the rake wear mechanism of the two cutting tools is a mixture of abrasive, oxidation, and other types of wear, whereas their flank wear mechanism is dominated by abrasive wear. With an aggravation of the tool wear, the oxidation and diffusion wear mechanism are both increasingly strengthened. The rake wear of the cutter with a variable chamfered edge showed an obvious increase in the oxidation and diffusion wear, as did the flank wear of the cutter with an invariable chamfered edge. This study revealed the wear mechanism of the PCBN tool with a variable chamfered edge and provided theoretical and technological support for its popularization and application in the machining of high-hardness materials.
基金supports of Hebei province high-tech industry multiplier project(No.16211702D)Chengde science and technology&development project(No.20152013).
文摘In order to analyze the influence of the hole chamfer on the metering performances of a Multi-hole Orifice Flowmeter and optimize the related orifice structure,a multi-hole orifice flowmeter with DN80 and throttle ratio of 0.45 was considered in the present study.The flow field characteristics were determined in the framework of a CFD technique.The results show that the multi-hole orifice flowmeter with filleting transition around the throttle orifice has higher accuracy in a wide range of the space of parameters,and is more suitable for accurate measurement of fluid in process control.
基金supported by the Hi-Tech Research and Development Pro-gram (863) of China (Nos. 2007AA01Z311 and 2007AA04Z1A5)the Doctoral Fund of MOE of China (No. 20060335114)the Science and Technology Program of Zhejiang Province, China (No. 2007C21006)
文摘We present a robust mesh sharpening approach to reconstructing sharp features from blended or chamfered features, even with noise and aliasing errors. Feature regions were first recognized via normal variation according to the user's input, and then normal filtering was applied to faces of feature regions. Finally, the vertices of the feature region were gradually updated based on new face normals using a least-squares error criterion. Experimental results demonstrate that the method is effective and robust in sharpening meshes.
基金This study was funded by the National Natural Science Foundation of China(Nos.51878354&51308301)the Natural Science Foundation of Jiangsu Province(Nos.BK20181402&BK20130978)+2 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX20_0885)Six talent peak high-level projects of Jiangsu Province(No.JZ-029)Qinglan Project of Jiangsu Higher Education Institutions.
文摘Eccentric compression tests on 15 chamfered laminated bamboo lumber(LBL)columns with a height ranging from 600 to 3000 mm were conducted in order to study the eccentric mechanical performance.The failure of all specimens was caused by the crack of bamboo fiber in the tensile region.When the ultimate strength was reached,except specimens with a height of 600 mm,all other specimens could bear large deformation,showing good ductility.The lateral displacements of the specimens under eccentric compression were approximately para-bolic in the direction of column height.The ultimate bending moment of LBL columns with different slenderness ratios under compression with the same initial eccentricity was a fixed value.The relationship between ultimate capacity,axial displacement,lateral displacement,and slenderness ratio was analyzed based on test results.It was found that the plane section assumption could be used to express the stress and strain distribution of chamfered LBL columns under eccentric compression.A method for calculating the ultimate bearing capacity was proposed using a constitutive model based on the Ramberg-Osgood relation and the empirical formula for calculating the ultimate capacity was given on the basis of the former research as well as the test results in this paper.
文摘Chamfered mould has gradually become a new technology equipment to eliminate transverse corner crack.However,longitudinal corner crack ratio of chamfered slab was very high.Solidification microstructure was detected in the area where the longitudinal corner crack occurred.Effect of narrow face shape and taper distribution of mould copper plate on longitudinal corner crack was studied by industrial tests.Water velocity distribution in the narrow copper plate was studied by numerical simulation.On the premise of preventing cooling water from nuclear boiling,improvement measures of mould cooling process and water seam structure were put forward through heat transfer calculation.The results showed that local taper of the meniscus region of mould should be increased to prevent generation of longitudinal corner crack.Chamfering slope length of narrow copper plate should be controlled within 55 mm,and chamfering angle should be controlled at about 30°.Average water velocity should be more than 7.0 m/s.The flat and chamfering regions of narrow copper plate working face should be designed as double taper and funnel structure,respectively.The water seam in the chamfering region should preferentially choose the combined cooling structure with two holes and one slot.In order to prevent the extension of longitudinal corner crack,chamfered narrow face foot roller should be used.
