Design, Analysis and Experimental Study of a Fine-Finish Power Supply for Wire-EDM

• Main Authors: Yi-Ting Liu, 劉奕廷
• Other Authors: Mu-Tian Yan
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/87857549710984348700

碩士 === 華梵大學 === 機電工程學系博碩專班 === 96 === This paper presents the development of a new fine finish power supply in wire-EDM using fixed width modulation (FWM) pulse control method. A spark gap model using a RLC circuit and a Zener diode has been developed for circuit simulation and analysis. The developed power supply using anti-electrolysis circuitry and DSP-based pulse control circuit can provide very low discharge energy pulses with a frequency of 4.4 MHz, a discharge duration of 80 ns and a peak current of 0.25 A. Experiments have shown that a on-time ratio (defined as a ratio between pulse on-time for negative polarity and that of negative polarity) of 3 can reduce the electrolytic effect of tungsten carbide for the machining conditions of high control frequency more than 500 KHz. Experimental results not only validate the applicability of the developed fine finish power supply in eliminating titanium’s bluing and rusting effect and reducing micro-cracking in tungsten carbide caused by electrolysis and oxidation, they also demonstrate that the developed system can achieve a fine surface finish as low as 0.16 μm Ra. Keywords：Wire-EDM, Fine finish power supply, Surface roughness, Anti-electrolysis