Papers by Author: Zheng Yang Xu

Abstract: A new flexible feeding ECM machine has been presented in the paper. The rational optimization rules of cathode’s feeding are proposed. According to analysis of a three dimensinal complicated surface’s shaping process, the cathode’s feeding route is optimized. Instead of feeding at a constant angle the cathode in the paper can feed flexibly during the ECM process. Finally the analysis result of distribution of inter-electrode gap has shown that the optimized feeding route do help to improve the workpiece’s accuracy.

Abstract: The electro discharge machining (EDM) process is widely applied to produces surfaces of difficult-to-machine materials that require some form of grinding or finishing operation. This is conducted so as to improve the surface texture and appearance of the component’s surface. However, it is also desirable to remove the white uppermost recast layer or damaged surface layer (produced by the EDM process) in order to improve the functional performance of the surface. The finishing of the surface by traditional manual methods, especially in the operation of small and long internal cylinder surface, is both tedious and time-consuming. A novel electrically conductive diamond mounted point electrochemical grinding (DMP-ECG) process is being developed for hard passive alloys unclosed internal cylinder surface grinding. The process mechanism of DMP-ECG is introduced; the influence parameters of the surface roughness, machining accuracy, and diamond tool wear are investigated experimentally for nickel-based super alloys materials. An application of the DMP-ECG to aircraft engine component is verified in term of the optimized process parameters.

Abstract: An experimental study on induction brazing diamond grinding wheel with Ni-Cr filler alloy was carried out. Brazing trial was conducted at the temperature range of 1020-1080 oC and the brazing time were 10, 20, 30 and 40 seconds in a flowing argon environment with a flow rate of 5000cm3/min. The scanning electron microscopic (SEM) results indicate that good wetting existed between the brazing alloy and diamond. The element distribution of C, Cr, Si and Ni were examined by energy dispersive spectrometer (EDS), the results demonstrated an intermediate layer rich in the chromium formed between the filler metal and diamond. Kinds of compounds formed in the interface were detected by means of x-ray diffraction (XRD), and the graphitization of the brazed diamond grits was determined by Raman spectroscopy. The monolayer induction brazing diamond grinding wheels were used in grinding of nature granite, experimental results show that induction brazing wheels performed better than vacuum brazing diamond wheels, and no pullout of diamond grits or peeling of the filler metal layer took place.