Effect of nano fluid and number of pulses on glass drilling using CO2 laser

This paper presents the influence of Nano fluid on the CO2 laser drilling of soda-lime glass. The glass thickness of 1.1 mm was immersed 1mm below the Nano fluid using liquid-assisted laser processing (LALP) technique, in order to reduce the temperature gradient, bulges and heat-affected zone (HAZ) region as a method for achieving crack-free glass machined holes. A glass sheets of 1.1mm thickness were drilled by CO2 laser. The samples immersed in colloidal prepared from mixing of Carbon Nano particles (CNPS) in de-Ionized water. Three different weight concentrations of CNPs were prepared. Three responses were measured; crack length, inlet diameter and exit diameter. The laser parameters were 10.6 µm wavelength, 0.25mm diameter, Semi Gaussian Beam, 20 W power, 0.5 sec exposure time and from single to six pulses were shooted. The drilled holes visualized using optical transmission microscope, then the obtained images analyzed using ImageJ software to measure the requested parameters. As results, when the no. of pulses increased, the diameter of the hole increased too. The length of cracks is reduced when the number of pulses increases. The better result of was 0.406 mm obtained at 0.1 wt. % of CNPS and single pulse for the inlet hole diameter, whereas the exit diameter was 0.247 mm at 3 pulses and same concentration of colloidal, and the crack length was 0.141 mm calculated at six pulses and same concentration. Besides, the parameters were theoretically evaluated by the design of expert software, using response surface methodology, through Box Behnken design of the response technique, and significant results were gained.