Modeling of material removal rate in rotary ultrasonic machining: designed experiments

Advanced ceramic materials have many potential engineering applications. However, their widespread applications have been hindered by the high machining cost. There is a critical need for cost-effective machining processes for advanced ceramics. Rotary ultrasonic machining (RUM) is a hybrid machining process that combines the material removal mechanisms of diamond grinding and ultrasonic machining (USM), resulting in higher material removal rates (MRR) than those obtained by either diamond grinding or USM. An approach to modeling the MRR during RUM of ceramics has been proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. Relationships between MRR and the controllable machining parameters have been deduced. These relationships agreed well with the trends observed by experimental observations made by other investigators. However, the relationships have been studied by changing one variable at a time. Therefore, the interactions between these variables have not been revealed. In this paper a five-factor two-level factorial design is used to study the relationships between MRR and the controllable machining parameters. This study will provide the main effects of these variables, and two-factor interactions and three-factor interactions among these variables. The results will shed more light on the material removal mechanism in RUM. The comparison with experimental results will also serve as further validation of the model.