This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughnes...This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughness of C/C composite and Duralumin, the 2D evaluation method of the cutting surface topography of C/C composite loses a lot of information, and the characteristics of the surface topography of C/C composite can be comprehensively and authentically evaluated only by the 3D evaluation method. Furthermore, 3D amplitude and spatial parameters are adopted to evaluate the surface and the results show that： the topography of the C/C composite is anisotropy and there are no obvious feeding textures but abrupt peaks and valleys on surface of the C/C composite, which indicates that the machining mecha- nism is different from that of the metal. In conclusion, The C/C composite surface is evaluated using a 3D evaluation method, the roughness error is small, and the unique topography characteristics earl be au- thentically evaluated.展开更多
A magnet is an important component of a speaker,as it makes the coil move back forth,and it is commonly used in mobile information terminals.Defects may appear on the surface of the magnet while cutting it into smalle...A magnet is an important component of a speaker,as it makes the coil move back forth,and it is commonly used in mobile information terminals.Defects may appear on the surface of the magnet while cutting it into smaller slices,and hence,automatic detection of surface cutting defect detection becomes an important task for magnet production.In this work,an image-based detection system for magnet surface defect was constructed,a Fourier image reconstruction based on the magnet surface image processing method was proposed.The Fourier transform was used to get the spectrum image of the magnet image,and the defect was shown as a bright line in it.The Hough transform was used to detect the angle of the bright line,and this line was removed to eliminate the defect from the original gray image;then the inverse Fourier transform was applied to get the background gray image.The defect region was obtained by evaluating the gray-level differences between the original image and the background gray image.Further,the effects of several parameters in this method were studied and the optimized values were obtained.Experiment results show that the proposed method can detect surface cutting defects in a magnet automatically and efficiently.展开更多
Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and t...Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and the rock particles. The recycling abrasive particles were then dried and sieved for determination of their disintegration behaviors. Before each cutting with recycling abrasives, the abrasive particles less than 106 ?m were screened out. It is revealed that a considerable amount of used abrasives can be effectively reused in the rock cutting. The reusabilities of abrasives are determined as 81.77%, 57.50%, 34.37% and 17.72% after the first, second, third and fourth cuttings, respectively. Additionally, it is determined that recycling must be restricted three times due to the excessive disintegration of abrasives with further recycling. Moreover, it is concluded that cutting depth, kerf width and surface roughness decreases with recycling. No clear trend is found between the kerf taper angle and recycling. Particle size distribution is determined as an important parameter for improving the cutting performance of recycling abrasives.展开更多
White layers in hard turned surfaces were identified and measured as a function ot turning parameters based on the Taguchi method. It reveals that white layers generate on the machine surface in the absence of tool fl...White layers in hard turned surfaces were identified and measured as a function ot turning parameters based on the Taguchi method. It reveals that white layers generate on the machine surface in the absence of tool flank wear, and white layer depth varies with the different combinations of hard turning parameters. Turning speed has the most important impact on white layer depth, feed rate follows, and cutting depth at last. The white layer generation consequently suggests a strong couple relation to the heat generation and thermal process of hard turning operation. White layer disappears under an optimal combination of turning parameters by Taguchi method. It suggests that a superior surface integrity without white layer is feasible under some selected combinations of turning parameters by a sharp CBN cutting tool.展开更多
Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditiona...Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining（WEDM） characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means（ANOM） and analysis of variance（ANOVA） on signal to noise（S/N） ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate（MRR） and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.展开更多
Grains in the slurry can be brought into cutting zone by steel wire with a certain speed to achieve the purpose of removing the workpiece material in the free abrasive wire sawing machining. Because its own of multi- ...Grains in the slurry can be brought into cutting zone by steel wire with a certain speed to achieve the purpose of removing the workpiece material in the free abrasive wire sawing machining. Because its own of multi- strands characteristics, we use it to replace the steel wire to do slicing experiment. In this paper, multi-strands wire is made by seven metal wires and has many grooves on its surface. Compared with steel wire, it can carry more grains into cutting zone which is conducive to improving the slicing efficiency. We do some comparative slic- ing experimcnts by applying multi-strands wire （~b0.25 mm） and steel wire （~b0.25 mm） to cut optical glass （K9）. The results show that slicing efficiency and the surface roughness of the workpiece sliced by using multi-strands wire are better than that by using steel wire. but the kerf width of the former is wider than that of the latter in the same experimental conditions.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
We consider a symbolic coding of bi-infinite non periodic geodesics on the L-shaped translation surface tiled by three squares. Each bi-infinite non periodic geodesic is associated with a cutting sequence correspondin...We consider a symbolic coding of bi-infinite non periodic geodesics on the L-shaped translation surface tiled by three squares. Each bi-infinite non periodic geodesic is associated with a cutting sequence corresponding to the sequence of labeled saddle connections hit. We prove that there is a relationship between the cutting sequences and the actions of some affine automorphisms of the translation surface. We also get an explicit formula to determine the direction of a bi-infinite non periodic geodesic by using the corresponding cutting sequence.展开更多
基金Supported by the National Natural Science Foundation of China (No. 50875036)
文摘This paper aims to establish a 3D evaluation method for cutting surface topography of C/C composites. The cutting surface is measured by Talyscan 150, using 3D non-contact measurement. By evaluating 2D and 3D roughness of C/C composite and Duralumin, the 2D evaluation method of the cutting surface topography of C/C composite loses a lot of information, and the characteristics of the surface topography of C/C composite can be comprehensively and authentically evaluated only by the 3D evaluation method. Furthermore, 3D amplitude and spatial parameters are adopted to evaluate the surface and the results show that： the topography of the C/C composite is anisotropy and there are no obvious feeding textures but abrupt peaks and valleys on surface of the C/C composite, which indicates that the machining mecha- nism is different from that of the metal. In conclusion, The C/C composite surface is evaluated using a 3D evaluation method, the roughness error is small, and the unique topography characteristics earl be au- thentically evaluated.
基金Project (51575542) supported by the National Natural Science Foundation of ChinaProject (2016CX010) supported by the Innovation-Driven Project of CSU,ChinaProject (2015CB057202) supported by the National Basic Research Program of China
文摘A magnet is an important component of a speaker,as it makes the coil move back forth,and it is commonly used in mobile information terminals.Defects may appear on the surface of the magnet while cutting it into smaller slices,and hence,automatic detection of surface cutting defect detection becomes an important task for magnet production.In this work,an image-based detection system for magnet surface defect was constructed,a Fourier image reconstruction based on the magnet surface image processing method was proposed.The Fourier transform was used to get the spectrum image of the magnet image,and the defect was shown as a bright line in it.The Hough transform was used to detect the angle of the bright line,and this line was removed to eliminate the defect from the original gray image;then the inverse Fourier transform was applied to get the background gray image.The defect region was obtained by evaluating the gray-level differences between the original image and the background gray image.Further,the effects of several parameters in this method were studied and the optimized values were obtained.Experiment results show that the proposed method can detect surface cutting defects in a magnet automatically and efficiently.
文摘Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and the rock particles. The recycling abrasive particles were then dried and sieved for determination of their disintegration behaviors. Before each cutting with recycling abrasives, the abrasive particles less than 106 ?m were screened out. It is revealed that a considerable amount of used abrasives can be effectively reused in the rock cutting. The reusabilities of abrasives are determined as 81.77%, 57.50%, 34.37% and 17.72% after the first, second, third and fourth cuttings, respectively. Additionally, it is determined that recycling must be restricted three times due to the excessive disintegration of abrasives with further recycling. Moreover, it is concluded that cutting depth, kerf width and surface roughness decreases with recycling. No clear trend is found between the kerf taper angle and recycling. Particle size distribution is determined as an important parameter for improving the cutting performance of recycling abrasives.
基金The Ministry of Education of China"985"of International cooperation project"Clean Manufactur-ing Technology"
文摘White layers in hard turned surfaces were identified and measured as a function ot turning parameters based on the Taguchi method. It reveals that white layers generate on the machine surface in the absence of tool flank wear, and white layer depth varies with the different combinations of hard turning parameters. Turning speed has the most important impact on white layer depth, feed rate follows, and cutting depth at last. The white layer generation consequently suggests a strong couple relation to the heat generation and thermal process of hard turning operation. White layer disappears under an optimal combination of turning parameters by Taguchi method. It suggests that a superior surface integrity without white layer is feasible under some selected combinations of turning parameters by a sharp CBN cutting tool.
文摘Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining（WEDM） characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means（ANOM） and analysis of variance（ANOVA） on signal to noise（S/N） ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate（MRR） and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.
基金National Natural Science Foundation of China(No.51075367)Natural Science Foundation of Zhejiang Province(No.Y1090931)
文摘Grains in the slurry can be brought into cutting zone by steel wire with a certain speed to achieve the purpose of removing the workpiece material in the free abrasive wire sawing machining. Because its own of multi- strands characteristics, we use it to replace the steel wire to do slicing experiment. In this paper, multi-strands wire is made by seven metal wires and has many grooves on its surface. Compared with steel wire, it can carry more grains into cutting zone which is conducive to improving the slicing efficiency. We do some comparative slic- ing experimcnts by applying multi-strands wire （~b0.25 mm） and steel wire （~b0.25 mm） to cut optical glass （K9）. The results show that slicing efficiency and the surface roughness of the workpiece sliced by using multi-strands wire are better than that by using steel wire. but the kerf width of the former is wider than that of the latter in the same experimental conditions.
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.
基金supported by National Natural Science Foundation of China(Grant No.11371035)
文摘We consider a symbolic coding of bi-infinite non periodic geodesics on the L-shaped translation surface tiled by three squares. Each bi-infinite non periodic geodesic is associated with a cutting sequence corresponding to the sequence of labeled saddle connections hit. We prove that there is a relationship between the cutting sequences and the actions of some affine automorphisms of the translation surface. We also get an explicit formula to determine the direction of a bi-infinite non periodic geodesic by using the corresponding cutting sequence.
