Papers by Author: Zhao Hui Deng

Abstract: Grinding Mechanism is very complex and difficult, and it can be simplified to a single abrasive grain grinding research. With the analysis of process and result of single abrasive grain grinding from experiment, the purpose can be achieved of understanding the complexity of the grinding mechanism. According to the characteristics of grinding process, the current domestic and international research status of single abrasive grain grinding experiments is introduced. The different experimental methods used by scholars are analyzed in detail, as well as grinding characteristics of single abrasive grain and chip formation mechanism of different characteristics materials. Finally, the current research difficulties of theory and experiment research are analyzed for the single abrasive grain grinding, and the further research direction is made.

Abstract: As one of the important input parameters in the grinding process, the surface topography characteristic of grinding wheel has a decisive impact on the grinding performance. To evaluate and analyze the microscopic surface topography, the premise must be able to detect the microscopic surface topography accurately. Based on the measurement of detection device and its spatial position, the surface topography detection methods have been classified, the principle has been specifically analyzed for some typical detection methods, and the research work done by domestic and foreign scholars in the area. Finally, the current problems and future research direction in the field have been analyzed.

Abstract: Grinding, as the last process of most products, directly affect the machining accuracy and surface quality of the product. Multi-parameter input and output and nonlinear mapping between the parameters of the grinding process play the most important part of computer simulation applied to grinding process. In this paper, the theory of computer simulation was introduced and a detail research on status of grinding process model and grinding process simulation system at foreign and domestic were elaborated, focused on the foreign academic research in this area. In the end, the paper presents an outlook of the research of grinding process simulation system.

Abstract: To investigate the distribution of cutting temperature for surface cutting of nanastructured WC/12Co coating used the PDC cutter, according to machining properties of WC/12Co coating and working conditions, on the basis of the theory of thermal equilibrium of moving thermal source, the mathematical model of temperature field was established through reasonable hypothesis. Simulations were performed for the temperature distribution on the surface and inside the WC/12Co coating specimen using finite element method. And experiment of surface temperature of WC/12Co coating used the PDC cutter was carried out. The finite element simulation results were in good agreement with the experiment data, which verified the validation and capability of the finite element model.

Abstract: By applying chemical-mechanical polishing (CMP) technique to high precision processing of rotary surface workpieces of silicon nitride (_Si3N4) ceramic, a CMP experimental device was established on a numerical control (NC) jig grinder. The polyurethane wheel and nonwoven cloth wheel was adoped. The Ce_O2 abrasive was applied to configure the water base polishing solution. Using Taguchi robust design method, through S/N ratios and analysis of variance, the influence of slurry concentration, polishing wheel speed and polishing wheel feed rate on material removal rate (MRR) were analyzed. With the increase of polishing wheel speed and polishing wheel feed rate, the MRR decreased. There was a balance concentration leading to the largest MRR. The best process parameters were selected: the slurry concentration of 20%, polishing wheel speed of 6000r/min, polishing wheel feed rate of 2.29mm/min, The result showed the descending order of selected process parameters impacting on MRR was polishing wheel speed, polishing wheel feed rate and slurry concentration.

Abstract: The NC grinding of Si3N4 ceramics rotary curved surface workpieces was carried on the CNC jig grinders, combining the nomal tracing grinding and the arc envelope forming grinding. According to the grinding track, a grinding surface scallop height model was built. The model analysis indicated that workpiece curvature, wheel radius and feed rate affected the surface roughness. A prediction model based on the response surface methodology (RSM) was built to study the influences of these processing parameters on the surface roughness, using the Box-Behnken design to design the grinding experiments. It was shown that the surface roughness of rotary curved surface workpieces grinding which increased with increasing workpiece curvature could be reduced by chosen larger radius wheel and lower feed rate. The confidence and practicality of the prediction model is high in experimental conditions. The process parameters can be selected to improve the quality of the surface based on the model of the paper.

Abstract: It is achieved that abrasive grains could be ordered on the surface of a grinding wheel using modern manufacturing methods. The excellent feature of a grain-arranged grinding wheel is that it can increase the proportion of active grains, improve the cutting efficiency, increase the chip volume space, effectively reduce the grinding temperature, prolong the service life of the grinding wheel and improve the surface finish of workpiece. Consequently, in the area of academic and industry the research of a grain-arranged grinding wheel has become a hot research topic, and more and more scholars focus on the research of the grain-arranged grinding wheel. In this paper, distribution patterns of abrasive grains were introduced; molding techniques for distributing abrasive grains were summed up; progress in research and future research trends of a grain-arranged grinding wheel was presented.

Abstract: A new polycrystalline diamond compacts (PDC) cutter was designed and prepared. The new PDC cutter has fibers that are artificially ordered so as to have the desired geometric angles, and it has a larger number of the cutting edges, enough space for holding chips and interrupted cutting so that it is easier to release heat. According to machining properties of materials and working conditions, on the basis of the theory of thermal equilibrium of moving thermal source, the paper established the mathematical model of temperature field of interrupted cutting used the PDC cutter through reasonable hypothesis. Simulations were performed for the temperature distribution in the tool-work interface and inside the Al₂O₃ ceramic specimen using finite element method. And experiment of surface temperature of Al₂O₃ ceramic interrupted cutting used the PDC cutter was carried out. The validation and capability of the finite element model were demonstrated by a satisfying agreement between the finite element simulation results and experimental ones.

Abstract: Virtual camshaft part is a very important information carrier for camshaft virtual high-speed grinding. The veracity and maturity of process correlation information, which holding on the virtual camshaft part, will directly determine the virtual high-speed grinding results’ authenticity and practicability. By analyzing geometrical structure and all kinds of process correlation attribute information, a method of process information parameterization of camshaft part for virtual high-speed grinding was presented in this paper, and a practicable function module of camshaft virtual part parameterization define was developed according with this mind.

Abstract: In order to solve the problem that selecting process parameters is difficult and inefficient in NC camshaft grinding, a case-based process expert system is presented, which takes frame method to present cases and utilizes case-based reasoning as the core mechanism of system. One of the typical cases of NC camshaft grinding which are stored in the case base of expert system is composed of three parts including description, solution and evaluation. The expert system generates a new case description according to the characteristics of camshaft to be processed, then forms an evaluation parameter from the similarity and the confidence. In the end, process intelligent matching is obtained by applying the system.