Ultrasonic elliptical vibration assisted machining (EVAM) was introduced in the mid nineties as an improved method for ultraprecision machining [1]. EVAM applies micrometer scale elliptical motion to a tool tip that has shown to reduce tool forces and improve tool life and surface finish. It is also used to machine workpiece materials, such as steel, that otherwise cannot be diamond turned due to excessive chemical tool wear. In addition to forming smaller chips, the EVAM tool periodically comes out of contact with the workpiece, thereby allowing it to cool between cuts and reduce the tool temperature. This is perceived as the reason for reduced thermochemical wear observed by researchers [2]. The complicated relationship between speed, depth of cut, frequency, ellipse shape, and tool temperature pose a challenging heat transfer problem. Finite element analysis of the EVAM process allows the dynamic, transient tool temperatures to be calculated. Metal cutting finite element software called AdvantEdge, by ThirdWave Systems Inc., provides the first available FE models of the EVAM process. A chemical wear model based on the Arrhenius equation for chemical kinetics has been previously introduced and used in conjunction with AdvantEdge tool temperature results [3]. This paper introduces further finite element modeling of the EVAM process. A parametric study is conducted to predict tool life as a function EVAM parameters in an effort to optimize the process. This information will be used in future EVAM actuator design.
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