Experimental investigation on fiber laser micro drilling of Titanium grade 5: fabrication, nature-inspired optimization and analysis through image processing

Abstract This investigation showed that micro holes were created on Titanium grade 5 substrate surface using a 30 W fiber laser. The impact of the control factors such as scan speed, frequency, number of passes and power were studied on the responses namely heat affected zone (HAZ), hole circularity (HC) and deviation in diameter (DIV). The control factors were optimized using firefly algorithm. Mathematical models were developed for each response having significant R-square value. 3D surface plots were used to examine how the control parameters affected the response. The firefly algorithm identifies the optimal conditions for micro drilling as scan speed of 210 mm s −1 , frequency of 40 kHz, power of 8 W and total of 40 passes which improved experimental findings i.e. HC-0.974, DIV-37.02 μ m and HAZ-19.53. After comparing the predicted values with the experimental findings, it was observed that the prediction error is lowest for HC (1.23%) followed by DIV (13.9%) and HAZ (16.9%). Image processing technique was used to convert regular images into a digital format to extract useful information.