The Optimization Of The Pulsed Nd:YAG Laser Welding Process Parameters Based On The Taguchi Method

Due to the advantage of high energy density,low heat affected zone,low shape distortion of components,high welding speed,the research of the laser welding is the focus of the laser process.In laser welding ,as the welding quality would always been affected by the welding parameters,especially the parameters of the pulsed laser welding,so it is very important to develop proper experimental designs and statistical methods for optimal welding quality.In addition,the research of the welding mode of the low power laser and the calculation the melting ratio of the overlap pulsed laser welding is another research focus in the recent years,so it is also significant to do the reseach on these two aspects.The bead-on-plate of the SUS304 stainless steel was done by the low power pulsed Nd: YAG laser,the butt laser welding of the SUS304 stainless steel was designed and analysed by the Taguchi which is a advanced DOE method.The research of Taguchi method in laser welding ,the welding mode of the low power laser and the welding ratio of the overlap pulsed laser welding was done systematically.Firstly, The bead-on-plate of the SUS304 stainless steel which is 0.95mm thick was done by the low power pulsed Nd: YAG laser,the affect of the welding parameters such as voltage, pulsed width,frequency,welding speed on the welding width and welding aera was done in order to select the range of the welding parameters and determine the transformation of the laser welding mode.So as to furtherly,the range of the laser welding on the 0.95mm thick SUS304 stainless steel is U:410V-470V, Tp: 2-6ms,f:4-7,v:70-160mm/min.In addition,in laser welding process ,when Tp=4ms,f=4Hz,v=100mm/min, the conduction welding mode will transform into the keyhole welding mode when U≧ 430V;when U=450V , f=4Hz,v=100mm/min, the conduction welding mode will transform into the keyhole welding mode when Tp≧ 4ms,so this can be somewhat indicative to select suitable parmeters to complete keyhole welding and improve welding efficiency.Secondly,the butt laser welding of 0.95mm and 1.45mm thick stainless steels were designed and analysed by Taguchi based on the single parameters laser welding.The experimental results was analysed by signal to noise ratio and ANOVA using the software Minitab and Design expert,the effect of the laser welding parameters voltage, pulsed width,frequency,welding speed on the welding width,welding area,melting ratio and tensile strength were investigated,the mathematical modes were built in order to optimize and predict the experimental result.As a result,the mathematical models are feasible by the ANOVA,the difference between the predicted optimal experimental results and the experimental results verified are acceptable,this will be the foundation of the optimization of the welding parameters.Among them,based on the overlap pulsed laser welding ,the principle of the melting ratio to this welding method was described,the Taguchi method was used to improved the melting ratio in the welding process and obtained a acceptable result,it is significant for computing the laser welding efficiency availably.In addition,the optimizations of the multi-results were executived to the many results,the predicted experimental results were got in different criterias.it provide a significant guidance for the purpose of the optimization to the complex experimental results.