Optimization of Laser Welding Parameters in Titanium Sheet Using Grey-Fuzzy Logic

Currently, the industrial market for structures and products have been gradually weakening along with industrial development. The stability of this market is also diversifying and being demanded with the concept of selecting lightweight and high strength materials. The titanium materials have come into the spotlight as materials that meet these needs. Therefore, In this study, an experimental method was established by using the orthogonal array table in the Taguchi method, and the SNR(Signal to noise ratio) is output to the tensile strength and bead shape through the welding experiment. Two parameters were defuzzification with using Grey-Fuzzy Logic for optimizing process considering the output variables, such as tensile strength and bead shape and output to Grey-Fuzzy Reasoning Grade(GFRG). This study was conducted by estimating the optimal input parameter with analysing the output GFRG by one-way ANOVA(Analysis of variance) method. In this paper, the optimal welding parameters for the lap welding of pure titanium material were selected as the welding speed of 2m/min, the laser power of 1.3 kW, the top shielding gas flow rate of 30l/min and the bottom shielding gas flow rate of 10l/min. Key words: Grey-Fuzzy logic, Welding parameter optimization, Pure Ti weldments, Lap joint, Disk laser welding