Drilling of Engineering Ceramics using Combination of Ultrasonic Vibrations and Diamond Slurry

Engineering ceramics due to their high strength-to-weight ratio, wear resistance, corrosion resistance, and thermal resistance have widely been used in the industries especially in aerospace, automobile, electronics and computers. In spite of their extensive application, however using conventional machining methods for manufacturing of complex and desired shapes are not suitable. Accordingly drilling holes with desired accuracy are difficult to be achieved. Ultrasonic machining (UM) is a modern machining method that is appropriate for creating holes in hard and brittle materials through ultrasonic vibrating applied to work piece by tools. Furthermore, abrasive slurry is applied through the gap between the tool and workpiece. In this paper modal analysis is used to choose the best shape for wave amplitude magnification and concentration. A desktop CNC milling machine is used for controlling feed motion of ultrasonic head upon a ceramic sample. Effect of input factors such as power, abrasive grit size, slurry concentration and feed rate are obtained on the material removal rate (MRR), tool wear rate (TWR) and hole over size (HOS) by Taguchi method. The results showed that between the input parameters, power is the most effective factor on MRR. Furthermore, grit size and feed rate are the most effective factors on TWR and HOS.