Laser welding optimization - Employing Taguchi orthogonal array

Abstract

The parametric design methodology is adopted to optimize the product and process design prior to production implementation. This methodology takes into account the quality index in the experimentation phase since so-called real-time quality control and/or SPC (statistical Process Control) can never fully compensate for unrealistic physical process variables. Targuchi methodology though used for other joining processes, is applicable to laser welding has never been realized. This paper discusses the laser welding optimization using Taguchi methodology. The Taguchi methodology used to optimize laser welding is a set of orthogonal arrays. The set used in this experiment is L8 orthogonal array. The L8 orthogonal array employs only 8 prototype trials while the equivalent conventional full factorial experiment would be 128. Though the designs sacrifice the effects of complex interactions of process variables, but the number of tests have been reduced 16-fold. The two level process variables-speed, shield gas, flow rate, nozzle diameter are used along with three beam parameters each also at two-level. Two material conditions are also experimented. The welding experiments were conducted on sheet steels in the butt joint configurations. A 10kW fast axial flow continuous-wave CO2 laser was used for all the trials. The laser welds were made transverse to the joint and parallel to the sheet rolling direction. The quality index of the laser welds were investigated through optical microscopy and visual inspections. Both testings were performed on all experimental conditions in the Taguchi array. The most significant process parameters are established that provides the highest quality index of the welds with regards to physical performance.The parametric design methodology is adopted to optimize the product and process design prior to production implementation. This methodology takes into account the quality index in the experimentation phase since so-called real-time quality control and/or SPC (statistical Process Control) can never fully compensate for unrealistic physical process variables. Targuchi methodology though used for other joining processes, is applicable to laser welding has never been realized. This paper discusses the laser welding optimization using Taguchi methodology. The Taguchi methodology used to optimize laser welding is a set of orthogonal arrays. The set used in this experiment is L8 orthogonal array. The L8 orthogonal array employs only 8 prototype trials while the equivalent conventional full factorial experiment would be 128. Though the designs sacrifice the effects of complex interactions of process variables, but the number of tests have been reduced 16-fold. The two level process variables-speed, shield gas, f...