The research of improvement of ECDM drilling quality

• Main Authors: Lun-Ching Wu, 吳倫靜
• Other Authors: 廖運炫
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/08352817174965385687

碩士 === 國立臺灣大學 === 機械工程學研究所 === 94 === This paper is aimed at the drilling quality improvement in electrochemical discharge machining (ECDM) process. The Sodium Dodecyl Sulfate (SDS) surfactant is added to the electrolyte and its effects on machining quartz are investigated. Experimental results show that the current density is increased, and there is more bubble release around the electrode as compared with that when machining in the electrolyte without SDS. As a result, the sparks become brighter and take place in a larger area. But on the other hand, a more stable pulse current is obtained. Hence, a less taper and a better quality but a little over size hole can be drilled with a higher engraving speed. The Taguchi L18 orthogonal array of experiment is adopted, and the appropriate machining parameters for various machining objectives are investigated. It is found that drilling with the use of SDS added electrolyte incorporated with the power source parameters of low voltage, pulse frequency and duty factor leads to a less taper hole. In order to reduce the over size error of a drilled hole, the use of electrolyte without SDS, low voltage and duty factor are recommended; while pulse frequency plays a minor role. When both of the over size and taper of a hole are concerned, machining should be conducted in the SDS added electrolyte using a smaller size electrode. A better quality hole can be drilled in less time. Furthermore, based on the observation of sparking process together with the experimental results, a new bubble forming mechanism during ECDM in the SDS added electrolyte is inferred.