線電極中超音波對線切割放電加工之影響

Abstract

超音波輔助線切割雖然已有許多研究，但仍有裝置設計上的限制而尚未在實務上被廣泛應用。從過去的研究中可得知超音波輔助可以提升線切割的加工效率，但少有研究專注觀察與探討這背後影響極間狀況的原理、成因，大多從實驗經驗去回推超音波振動設定上的建議與規則。 第一部份，本實驗嘗試改良超音波輔助線切割的裝置設計，可以不需再因工作區工件厚度與線極長度的改變而調整超音波輔助裝置的設計，透過此裝置發明可以更容易且穩定地使線極產生隨超音波振動的運動現象。 第二部份，本研究想了解線極在間隙中影響流場與碎屑的狀況，但因放電的靜電力等因素難以捉摸與觀測，因此先排除了放電的因素進行此觀察與分析，使用第一部份的超音波輔助裝置，透過觀察的裝置實際觀察與電腦上的流場模擬分析進行綜合探討。 由本研究結果顯示，超音波輔助線切割在加工液中產生的空化氣泡是主要影響碎屑分布的因素。

Although many researches have been done on ultrasonic-aided WEDM, there are still some limitations in device design, so it has not been widely used in practice. It can be known from past research that ultrasonic-aided can improve the efficiency of wire EDM cutting, but few studies have focused on observing and discussing the principles and causes behind the spark gap conditions. Most of the ultrasonic vibration settings have been introduced from experimental experience. In the first part, this study attempts to improve the design of the ultrasonic-aided WEDM device. It is no longer necessary to adjust the design of the device due to the change in the thickness of the workpiece and the length of the wire electrode in the working place. By this design, wire can vibrate with ultrasonic more stably and easily. In the second part, this study wants to understand how the ultrasonic-aided wire affects the flow field and debris in the spark gap. Because of the difficulty of observing electrostatic force of the discharge in the spark gap, the discharge factor is excluded first for this observation and analysis. A part of ultrasonic-aided phenomenon is discussed through the actual observation and the analysis of the flow field on the computer. The results of this study show that the phenomenon of cavitation bubbles generated in the machining fluid by ultrasonic assisted wire is the main factors affecting the distribution of debris.