Key Engineering Materials Vol. 416

Abstract: Magnetic-electrochemical compound polishing is applied in difficult-to-process materials little by little. The influence of the magnetic field to electrochemical process is very complicated. In the paper, using Coulomb laws and Lorentz force, the two kinds of math model of the movement of the charged particles are established according to the different magnetic field whose direction is vertical or parallel to the electrical field. The velocity equations and loci equations of three typical particles are concluded in two kinds of magnetic field’s directions. To be compared and analyzed carefully, the influence of the magnetic field’s direction to polishing is concluded. This study can guide how to determine the magnetic field’s direction in magnetic-electrochemical compound polishing, and build the theoretical basis to study the mechanism of magnetic-electrochemical compound polishing.

Abstract: To solve the problems of the reduces in belt life、low in metal removal rate and environmental pollution by using conventional grinding fluid, a new high efficiency and green cooling technology—— The Technology Of Liquid Nitrogen Cryogenic Wind Jet Combined MQL(LNCWJCM), It was used in belt grinding of TC4. The effect of LNCWJCM on grinding performance of TC4 was analyzed to compare with cold air 、liquid nitrogen and conventional flood cooling method. The experimental results indicate that LNCWJCM can improve metal removal rate and the life of belt, in addition , impacting on abrasive belt grinding from which the flow of liquid nitrogen, grinding temperature, the flow of oil droplets and other key parameters is studied.

Abstract: Point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding force. Because of the lower grinding power, the grinding heat in point grinding process is much less than that of the conventional grinding process. Therefore, the less grinding coolant jet parameters can be used during point grinding process. That is very propitious to the environment and resource, as well as the green manufacturing. Based on the mathematic model of the edge contact area of point grinding, the simulations of the edge contact area with point grinding angles and depth of cut was performed to study the grinding power. In addition, the relations between the grinding power and the depth of cut and vertical grinding angle were investigated. The dynamic pressure and velocity distributions in the airflow layer around the wheel edge were analyzed more by means of experiment. The point grinding experiment for grinding coolant jet parameters was performed.

Abstract: This paper describes the current situation of spherical grinding for carbide material. The experiment of Concave spherical ELID grinding of generating method for carbide is conducted. Because dressing electrode can’t be installed in limited space due to the small space of concave spherical surfaces and carbide material has good conductivity, the workpiece material was used as dressing electrode in the ELID grinding experiment. According to negative effect of spark discharge in the process of grinding to surface roughness, two methods "ELIDⅡ" and "ELID Ⅲ" were designed. Comparing and analyzing the experimental results, it is confirmed preliminary that the spherical error and surface roughness of the workpiece after "ELIDⅡ" grinding were better than those after the "ELID Ⅲ" grinding. The ELID grinding method using micro diamond powder wheel and using carbide workpiece as dressing electrode is an effective way for spherical ultra-precision grinding for carbide.

Abstract: An ultrasonic grinding technology named NC-Contour Evolution Ultrasonic Assisted Creep Feed Grinding that using a simple shaped diamond grinding wheel with small diameter is presented to solve the machining problem of ceramic blade surfaces in integral impeller, which is similar to numerical control profile modeling milling. The grinding parameters of single grit in the grinding wheel are selected as the objective to make clear the grinding properties of creep feed grinding and ultrasonic grinding using grinding wheel with small diameter so as to explore the suitable processing parameters to machine ceramic blade surfaces in integral impeller in theory.

Abstract: The abrasive ice disc chemical mechanical polishing (AID-CMP) is a potential polishing process in the semiconductor industry to realize superior surface finish and planarity for semiconductor wafers. In this paper we investigated the temperature field during GaAs wafer AID-CMP process for a better understanding of AID-CMP. The results show that the AID outer temperature is higher than the inner, and the highest temperature in AID is at the wafer/AID contact zone. The increases of Pc, v, eh and tp will generate more energy and cause more local melting during GaAs wafer AID-CMP process. The AID temperature and the area of highest temperature zone increase with increasing Pc, v, and eh. The nodes temperature increase in every conditions adopted as tp increases. The area of melted zone and thickness of melted ice increase with increasing Pc, v, eh and tp.

Abstract: According to the requirement for high-precision and processing features of the internal grinding, the hardware and software of an internal grinding NC system based on embedded system were presented. The classification and implementation of several key system tasks controlled by real-time operating system uc/os-ii were given, and the control process of the machine switch by soft PLC technology was elaborated on in the system. According to the real-time requirements of internal grinding NC system, the tasks of the system were prioritized reasonably, and some methods for enhancing the capability of real-time and improving the accuracy of the system were presented with software technology.

Abstract: Based on orthogonal experiment design the study about the irregular surface of Qilu Red granite was performed, the tend charts of technologic parameters were established. The relations of factor primary and secondary between cutting speed, feed rate and depth of cut on two performance measures, machining efficiency and wear of cutter were investigated by range analysis, and the optimal cutting parameters for each performance measure were obtained too. Mathematic models of machining efficiency and wear of cutter were deduced by analysis of regression about experimental results. The theoretic foundation was offered to reasonably select technologic parameters of grinding for irregular surface of granite.