Papers by Author: Bao Ji Ma

Abstract: Based on the concept of the interaction between a magnetic and electric field, a magnetic field was suppressed on the Electrochemical Machining (ECM) setup to improve the copying accuracy of ECM. Mathematical modeling and finite element modeling of the magnetic field was also developed using ANSYS to study the influence of permanent magnet design on the ECM process. The results indicate that by introducing the magnetic field the threshold of electrochemical reaction is decreased and the tracks of ions become complicated which makes the chemical reaction more extensive and more uniform in the inter-electrode gap. The distribution of magnetic field in the gap helps to improve the machining accuracy and the process efficiency, when the permanent magnet is at the end of the electrodes. Experiments have been carried out to validate the results of finite element analysis and the effect of a magnetic field on the ECM process is discussed.

Abstract: The purpose of this experimental research are investigation the growth behaviors of the oxide layer at different pre-dressing conditions in ELID pre-dressing, effects of voltage and duty ratio of the power supply, wheel speed on the oxide layer formation characteristics on the metal bond diamond wheel surface. The results indicated that the oxide layer thickness on the wheel surface increase with pre-dressing time. The oxide layer growth rate is faster in beginning period time of pre-dressing process then slow down. Both the thickness and growth rate of oxide layer increase with the increase of duty ratio and applied voltage. It takes longer time for oxide layer growth rate to reach to stable state in lower duty ratio condition than in higher duty ratio condition. There are no effects of wheel speed on oxide layer growth behaviors in the wheel speed range of 1000rpm to 4000 rpm.