Ultrasonic drilling (USD) is widely used for drilling of glass. A comparative study of USD for 2.0 mm diameter hole in 3.0 mm thick soda lime glass has been performed using static (USD-ST) and rotary tool (USD-RT) of mild steel. To make the process more cost effective and productive, statistical models of material removal rate (MRR), hole circularity at entry and exit (HCentry, HCexit) and hole taper (Ht) have been developed using Box–Behnken approach of response surface methodology. The effect of abrasive size, frequency, ultrasonic power and tool rotational speed have been investigated and it was observed that abrasive size is the most significant factor to control MRR during USD-ST. In USD-RT, MRR, HCentry, HCexit and Ht are significantly affected by frequency. The combination of low frequency and small grain size produces high MRR in USD-RT. Increase of frequency from 22 to 24 kHz increases HCentry by 4.3% in USD-ST, whereas for rotating tool the increase of frequency from 22 to 25 kHz decreases the value by 2%. HCentry increases with the rise of frequency at constant ultrasonic power, USD-ST provides 7.14% more circular hole at entry compared to USD-RT for a combination of frequency and grit size. In multi-objective optimization of USD-ST, a desirability value of 0.8589 was obtained at ultrasonic power of 90%, frequency 23.47 kHz and abrasive grit no 60, whereas for USD-RT the desirability value of 0.8499 were correspondingly obtained at 78.48%, 25.5 kHz, 770.20 rpm and 60.

Comparative analysis of ultrasonic drilling process using static and rotary tools

Soda–lime glass possesses high hardness and brittleness. Analysis of machining of soda–lime glass becomes essential as it is now being extensively used material for different engineering and medical purposes. The intrinsic characteristics of soda–lime glass make it difficult to machine materials. In this study, experimental modeling for material removal rate (MRR) and hole circularity has been performed using the response surface methodology (RSM) for ultrasonic drilling (USD) of 2 mm diameter hole in 3 mm thick soda–lime glass. The effect of input process parameters like ultrasonic power, frequency, and abrasive grit number has been analyzed on MRR and hole circularity. It was experiential that the effect of ultrasonic power on both MRR and hole circularity for different grit size is not very important. Abrasive with high grit number rises the MRR but declines the MRR after initial rise up to grit number of 40. At a specific ultrasonic power, the increase of frequency continuously increases the hole circularity, but in case of MRR, it begins to decrease after 23 kHz. The result of ultrasonic power on both MRR and hole circularity is nonlinear gradual decline up to 80 W further increase later.

Abhilash Kumar

Papers

Comparative analysis of ultrasonic drilling process using static and rotary tools

Modeling of Material Removal Rate and Hole Circularity on Soda–Lime Glass for Ultrasonic Drilling