Advances in Abrasive Technology IX

Paper Title Page

Authors: Hang Gao, W.G. Liu, Y.G. Zheng
Abstract: It is experimentally found that existing micro-holes or micro-concaves on the cemented carbide base surface of electroplated CBN wheel is one of important reasons to worsen the combining intensity of the electroplated abrasives layer with the grinding wheel base. It is well solved by sealing the holes or concaves with steam sealing method. Further more the electroplated CBN wheel with cemented carbide base for precision grinding of compressor cylinder vane slot is developed by optimizing the electroplating prescription and process. Productive grinding results show that the ground surface roughness, size precision and the wheel life have reached the advanced index of the same type of wheel imported.
Authors: Jiu Hua Xu, Wen Feng Ding, F. Qian
Abstract: The joining strength and corresponding fracture mechanism of the brazing interface between diamond grains and tool matrix is one of the primary problems in the development and application of brazed diamond grinding tools. In this study shearing tests were performed for the brazed joints, meanwhile the fracture mechanism and the joining characteristics were analyzed deeply. The results indicate that, depending on the metallurgical integration effect through the atom diffusion between the filler alloy and the metal matrix, and on the strong chemical bond by the new-formed Cr-C compounds between the filler alloy and diamond grains, hard and reliable joining is realized at the grain interfaces, which significantly supports the potential advantages of the latest brazed diamond grinding tools.
Authors: Ya Dong Gong, H. Li, Guang Qi Cai
Abstract: The airflow field of super-high speed grinding was analyzed in the paper and the method of computing and analyzing the distribution of the field has been brought forward by applying boundary layer theory. Adopting the method of finite element, the model of airflow field in the 3-D grinding zone has been built up by using software; the solving strategy and the boundary conditions has been defined, where artificial viscosity coefficient in the repetitive and continuous analysis and the method by applying inertia relaxation have been discussed, which helped to revolve stability. The results of simulation was given and analyzed, which can be validated with experiment by using the equipment of PIV (particle image of velocity).
Authors: Hua Fu, Bo Liao, Bao Chen Sun, Ai Ping Liu, Fang Juan Qi, Zhan Lai Ding
Abstract: A semi-metallic stainless steel/carbon fiber reinforced PEEK-based friction material was developed in this paper. The composite was PEEK 19.63wt%, stainless steel fiber 7.57 wt%, carbon fiber 10.97 wt%, cashew 6.51 wt% and fillers 55.33%. The molding process was blending for about 30 seconds at higher speed, pre-heating at the temperature of 80 for 30min, molding at 320 and pressure 35Mpa for 3min/mm, then post-curing at the temperature of 80 for 30min , 150 for 30min270 for 30min320 for 180min. The results of abrasion test showed that the developed material N3 had higher and steady friction coefficient and low abrasion value. The SEM morphology study showed that the wear mechanism was particle abrasion at low temperature but adherence abrasion as well as particle abrasion occurred at higher temperature. The cohesive strength of the composite and the heat-resistant property of resin matrix were the key factors affected wear loss. The abrasion depended on the strength of transformed films and matrix.
Authors: Moon Chul Yoon, Do Hun Chin
Abstract: There are many modelling methods using theoretical and experimental data. Recently, fractal interpolation methods have been widely used to estimate and analyse various data. Due to the chaotic nature of dynamic roundness profile data in roundness, some desirable method must be used for the analysis of data which is natural to sequential data. Fractal analysis used in this paper is within the scope of the fractal interpolation and fractal dimension. Also, two methods for computing the fractal dimension have been introduced, which can calculate the fractal dimension of typical dynamic roundness profile data according to the number of data points in which the fixed data are generally lower than 120 data points. This fractal analysis shows a possible prediction and analysis of roundness profile that has some different roundness profile in round shape operation such as cylindrical grinding, turning, drilling and boring.
Authors: Chang He Li, Guang Qi Cai, Shi Chao Xiu, Feng Liu
Abstract: Surface microcosmic topography finished by abrasive jet with grinding wheel as restraint was analyzed and evaluated. Generating mechanism of surface morphology finished by abrasive jet with grinding wheel as restraint was investigated and surface topographical characteristics were also evaluated with cross correlation of random process. Experiments were performed with plane grinder M7120 and workpiece material 45# steel which was ground with the surface roughness values of Ra=0.20.6m. The machined surface morphology was studied using SEM and microscope and the microcosmic geometry parameters were measured with TALYSURF5 instrument. The experimental results shown that the machined surface change from continuous and parallel micro-groove and plough to randomly discontinuous micro-pit can be observed with machining circles increasing and surface roughness was obviously improved. Furthermore, The finished surface has little comparability compared to grinding machining surface.The isotropy surface and uniformity veins both parallel and perpendicular machining direction were attained by abrasive jet precision finishing with grinding wheel as restraint.
Authors: Yong Hong Zhang, L.H. Wang, De Jin Hu
Abstract: Image analysis was used to evaluate the curve grinding process. The measurement system organization and its principle of operation were introduced. Some key technologies that influence the system precision were also studied in details. Real-time image of work piece and wheel grinding can be gathered while using CCD camera. For image de-noising, a kind of wavelet threshold function was presented to calculate the new wavelet coefficients. Local threshold algorithm was used to compute different scale threshold, another threshold is suggested when MSE is minimum. Image signals are reconstructed through invert discrete wavelet transformation with the new wavelet coefficients. For the purpose of increasing the measurement precision, a closed mathematical model of sub-pixel edge detection operator was founded according to the gray moment operator’s invariant characteristics and Tabatabai’s first three sample gray moments. An application of system validity and the comparison results of work piece were also given. From experiments it can be said that the proposed method in this paper is effective, and its detection precision and results are reasonable.
Authors: Ying Chun Liang, Yuan Sheng Zhai, H.X. Wang, Qing Shun Bai, Y. Zhao
Abstract: In precision turning, the quality of surface finish is an important requirement for machined workpiece. Thus, the choice of optimal cutting parameters is very important for controlling the required surface quality. The focus of the present study is to find a correlation between surface roughness and cutting parameters (feed rate, depth of cut) and nose radius in turning 3J33 maraging steel, and to derive mathematical models for the predicted surface roughness based on both of cutting parameters and nose radius. The experimental design is carried out using the quadratic rotary combination design. The regression analysis shows feed rate and nose radius influence surface roughness significantly. With F-ratio test the proposed model is adequate. The method could be useful in predicting roughness parameters as a function of cutting parameters and nose radius.
Authors: Dao Hui Xiang, Ming Chen, Y.P. Ma, Fang Hong Sun
Abstract: Despite great advancements in diamond thin film growth and deposition techniques, determination of the residual stress and Young’s modulus for diamond films has continued to be a challenge. The bulge test is a potentially powerful tool for characterizing the mechanical properties of diamond film. In a bulge tester, pressure is applied on a thin membrane and the out-of-plane deflection of the membrane center is measured. The Young’s Modulus and the residual stress are simultaneously determined by using the load-deflection behavior of a membrane. By means of electron-enhanced hot filament chemical vapor deposition (HFCVD), a diamond film was deposited on silicon slice (100), and the free-standing window sample of diamond thin films was fabricated by means of photolithography and anisotropic wet etching. The deflection of the membranes is measured using a laser interferometry system. The elastic modulus and residual stress were measured using a self-designed bulge equipment. In addition, the distortion of diamond thin films under different pressure was simulated using finite element analysis and the contrast was made with experimental data. The research indicated that the Young’s Modulus of diamond thin films is 937.8GPa and the residual stress is -10.53MPa. The elastic modulus and the residual stress coincide with the report in the literature and the value tested by X-ray diffraction, respectively. This method uses a simple apparatus, and the fabrication of samples is very easy, and it has provided an effective means for precise measure the mechanical properties of other thin films.
Authors: Xiao Gang Jian, L.D. Shi, Ming Chen, Fang Hong Sun
Abstract: Adhesion properties of diamond thin films are essential to their performance in technical applications. To obtain the adhesive strength precisely and quantitatively has been the frontier issue to the related scientists and engineers. In this paper, a new experimental equipment for blister tests was designed purposely and fabricated considering related influencing facts. A free-standing window of diamond thin film with the support of silicon wafer was obtained by the aid of photolithography and anisotropic wet etching technology so as to improve the precision of quantitative adhesion measures of diamond films. The mechanics for calculating the quantitative driving force of blister-induced delamination of diamond thin film is presented, which is on base of intensive modeling and simulation. The laser interferometer measurement with fine solution was used to pick up dynamic signals of diamond thin film bulge deformation in micrometer scale and the relationship demonstration of stress to strain of the diamond thin film was available, as a consequence, the adhesive strength could be obtained precisely and quantitatively by the valid model. The paper confirms the accessibility to precise quantitative adhesion measures of diamond films and the results will be beneficial to wide application of diamond thin films in the related fields.

Showing 81 to 90 of 129 Paper Titles