Key Engineering Materials Vols. 579-580

Abstract: In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.

Abstract: An experimental study of quartz glass grinding with ultrasonic torsional vibration assistance is presented. The grinding forces and surface roughness are measured. The results show that the grinding force and surface roughness with ultrasonic torsional vibration assistance are much less than those in conventional grinding. The grinding force increases with the feed rate of workpiece and the depth of grinding, and decreases with the speed of wheel spindle. This research indicates that the ultrasonic torsional vibration-assisted grinding can enhance grinding performance and be an effective method for the machining of hard and brittle materials.

Abstract: Aiming at globoidal cam one-side machining errors in addition to programming error, there exists combined effects of a number of the original errors, such as, machine motion error, tool error, fixture error and et al. On basis of the analysis of the principle of one-side processing, the theoretical calculation synthetic model of the one-side machining profile normal error is established based on the multi-body system error modeling theory and spatial mechanism conjugate meshing principle. And by applying Newtons iterative method and simulations in Matlab, the law of comprehensive influence of each original error on globoidal cam profile normal error is revealed. The simulation results verify the correctness of the theoretical calculation error synthetic model, and a scientific proof is provided for further improving machining accuracy of one-side machining of globoidal cam.

Abstract: Collaboration, cloud computing have been identified as key business technology trends that will reshape enterprises worldwide. Cloud manufacturing (CM) - the manufacturing version of cloud computing can be implemented by various approaches. A part model based on processing behavior was developed and the definition, classification and data structure expressed by XML were presented. Processing behavior as trading service unit, can be requested or responded by designer clients or manufacturer clients on the trading service platform. Meanwhile, the data exchange protocol and trading mechanism were analyzed, and the workflow of the trading service platform was given. Finally, a case study of manufacturing trading service platform was demonstrated, which enable designers and manufacturing to make a deal, exploring the specific application of could manufacturing.

Abstract: With high precision special rotary tool is widely used in automotive, mold, aerospace, machinery, electronics and other fields, the demand of manufacturing for such type and quantity of cutting tool is more and more big, lead to the demand for multi-axis CNC tool grinder which provides efficient, high quality production support for it also increasing. In terms of hardware and software multi-axis CNC tool grinder in developed countries are relatively mature, but domestic did not have enough for this research, especially for development of CNC tool grinding machine operation software system, and rarely reference data. In view of the domestic manufacturer in urgent need of independent research and development of CNC tool grinder, this article will research tool grinding automatic programming and simulation technology of CNC tool grinding machine operation software system, through analyzing the four main steps of NC grinding four-blade overall end milling cutter, parametric programming with MATLAB, and grinding trajectory data in the form of mixed programming of MATLAB and VC+ + will be post processed into NC programs, then simulation in VERICUT virtual machine tool, finally the actual grinding out overall end milling cutter.

Abstract: The temperature and carbon content at blow end point should be controlled strictly during the BOF converter steelmaking process. Meanwhile many factors have impact on the temperature and carbon content at blow end point. These factors include initial weight of molten iron, initial weight of scrap steel, oxygen blow duration, the temperature and carbon content when lowering the sublance, as well as the weight of all kinds of addition reagents. In order to determine the optimized process parameters so as to reach the ideal temperature and carbon content at blow end point, this paper built a series of experiment programs based on DOE. According to the experiment programs, authors conducted these experiments with the help of RBF neural network and analyzed each parameters as well as some interactions impact on target. According to the statistical analysis results of experiment data (the SNR), authors extract significant factors and reached an optimized process parameters A₃B₃C₂D₁E₁F₃G₂H₃J₂. According to the RBF neural network, the prediction error of carbon content and temperature is only 0.0063 and 0.0159 respectively. The result proves that DOE is an effective method in optimizing process parameters, and worth promoting and applying in converter steelmaking process.

Abstract: In order to better reveal the theoretical nature of internal ultrasonic grinding which is an efficient grinding technology, the characteristics of grits motion is analyzed under axial vibration and the grits kinematic equation is established. By using Matlab the single particles trajectory is simulated, then the displacement of a grit is given at any time they contact. Through the theoretical analysis and Matlab simulation, we can achieve that for axial ultrasonic vibration the influences of axial feed on the grits trajectory is too litter to be ignored. So when calculate the contact length of the grinding wheel and the work piece, the grinding wheels axial feed can be neglected. Then the contact length of the grinding wheel and the work piece is achieved. It has a significant value for simplifying the calculation of the grinding force and the analysis of internal ultrasonic grinding.

Abstract: Ni-ZrO₂-CeO₂ nanocomposites were prepared by double-pulse current in an ultrasonic field. The effect of average current density, duty ratio and frequency of double-pulse current on nanoparticles content of Ni-ZrO₂-CeO₂ nanocomposites was studied. Meanwhile, surface morphology and microhardness of nanocomposites were analyzed. The results show that, with the positive average current density, positive duty ratio and positive frequency increased, the nanoparticles contents increased at first and then decreased. On the contrary, it reduced while reverse average current density, reverse duty ratio and reverse frequency were increasing. Compared with Ni-ZrO₂-CeO₂ prepared by direct current and monopulse current, grain of Ni-ZrO₂-CeO₂ nanocomposite prepared by double-pulse current is finer, the microhardness is also higher.

Abstract: The conventional machining method for silicon nitride ceramics has low machining efficiency, prone to cracking, chipping and other defects. In this paper, the author carried out a study on the influence of ultrasonic vibration grinding on surface quality of silicon nitride ceramic, and carried out ultrasonic vibration grinding process test for silicon nitride ceramic and conducted the analysis of influence of this machining process on surface quality with orthogonal test. The test results showed that the influence on surface roughness decreased in the order of spindle speed, feed rate, cutting depth, and amplitude of vibration.

Abstract: TiO₂, as photosensitive materials, has attracted much attention owing to its potential application in the solution of environmental pollution during the past decades. Four doped TiO₂ systems were constructed and studied by using the first principle based Density Functional Theory .The results indicate that P-doped and N-doped TiO₂ all have better light absorption in the visible light area than pristine TiO₂ although the band gap of N-doped system reduced less. However, the band gap of F-doped and Cl-doped TiO₂ increase a little, which causing the absorption to decrease. We suggest from the results that the P atom and N atom are valuable in the modification of TiO₂.