Investigation on the Effects of Process Parameters on Laser Percussion Drilling Using Finite Element Methodology; Statistical Modelling and Optimization

Abstract

In the present research, the simulation of the Nickel-base superalloy Inconel 718 fiber-laser drilling process with the thickness of 1mm is investigated through the Finite Element Method. In order to specify the appropriate Gaussian distribution of laser beam, the results of an experimental research on glass laser drilling were simulated using three types of Gaussian distribution. The DFLUX subroutine was used to implement the laser heat sources of the models using the Fortran language. After the appropriate Gaussian distribution was chosen, the model was validated with the experimental results of the Nickel-base superalloy Inconel 718 laser drilling process. The negligible error percentage among the experimental and simulation results demonstrates the high accuracy of this model. The experiments were performed based on the Response Surface Methodology (RSM) as a statistical design of experiment (DOE) approach to investigate the influence of process parameters on the responses, obtaining the mathematical regressions and predicting the new results. Four parameters i.e. laser pulse frequency (150 to 550 Hz), laser power (200 to 500 watts), laser focal plane position (-0.5 to +0.5 mm) and the duty cycle (30 to 70%) were considered to be the input variables in 5 levels and four external parameters i.e. the hole's entrance and exit diameters, hole taper angle and the weight of mass removed from the hole, were observed to be the process output responses of this central composite design. By performing the statistical analysis, the input and output parameters were found to have a direct relation with each other. By an increase in each of the input variables, the entrance and exit hole diameters, the hole taper angel, and the weight of mass removed from the hole increase. Finally, the results of the conducted simulations and statistical analyses having been used, the laser drilling process was optimized by means of the desire ability approach. Good agreement between the simulated and the optimization results revealed that the model would be appropriate for laser drilling process numerical simulation.

Statistical and Numerical Approaches for Modeling and Optimizing Laser Micromachining Process-Review

“…RSM is a group of statistical and mathematical techniques that are useful for modelling and predicting the output of interest influenced by some input variables with the objective of optimising this output [8][9][10][11]. RSM also describes the relationships among one or more measured outputs and the vital controllable input factors [12].…”

Microstructural Design of the Cast Iron via Laser Hardening with Defocused Beam of the Continuous Wave CO2 Laser

“…Being, M 2 beam quality, FL focal length, λ wavelength and D raw beam size. Equation 3 [23,24] was used to calculate the Rayleigh length, ZR.…”

“…Z were from 0.0 to 5.6mm, which were increased 0.8mm. Do, according to Z were estimated by mean of equation 4 and these values are listed in Table 4 [14,22,24].…”

Experimental and Numerical Study of AISI 4130 Steel Surface Hardening by Pulsed Nd:YAG Laser

“…Among these processes, induced heat treatment and flame heat treatment are methods to improve steel surface hardness and wear resistance. While used for various industrial utilizations such as welding [1,2], drilling [3], and cutting [4], laser beam treatment is effective when a localized treatment is required [5]. In fact, laser has high accuracy and emits a centralized beam, which can be used for heat treating metal surfaces [6].…”