Experimental and statistical study for measurements of surface roughness and hole geometry of ultrasonic-assisted drilling of soda glass

Surface smoothness and accurate geometrical tolerances are crucial requirements for soda glass applications regardless their size. Ultrasonic-Assisted Drilling was introduced to achieve these requirements for hard-to-cut materials. A set of experiments is conducted for ultrasonic-assisted drilling of soda glass using coolant at high and normal tool abrasive concentration and multi-levels of feed rate and spindle speed. The mean surface roughness (Ra) and the geometrical tolerances of out-of-roundness, out-of-cylindricity and hole diameter oversize are measured. These responses are statistically analysed to define the significant factors and the optimum conditions for the responses. High feed rate increases the surface roughness (Ra) and reduces the out-of-roundness, out-of-cylindricity and hole-diameter oversize. The high tool concentration reduces surface roughness and out-of-cylindricity and oversize. The effect of the cutting speed is interacted with the tool concentration and the existence of slurry of coolant and chips causes excessive machining which affect the measured responses. Statically, feed rate is the most significant factor on all responses followed by the interaction of tool concentration and spindle speed. Lower feed rate, high spindle speed and high tool concentration are the optimum conditions for improving the surface and geometrical measures.