Optimisation Of Off-axis Laser Cutting Technological Parameters

With the continuous improvement of the laser cutting market on the quality of finished products,compared to developed countries,China’s laser cutting processing technology is slightly behind in cutting accuracy and cutting efficiency,and in the field of high-end laser cutting equipment manufacturing is also limited by the high power cutting head structure,high-speed high-precision machine tools,power fine control system and other technical deficiencies.Therefore,by adjusting the cutting technological parameters to improve the quality of laser cutting,boost the competitiveness of domestic enterprises in the field of laser cutting has an important role.In previous studies on cutting parameter optimization,the key technological parameters studied were mostly the output power,the feed rate,the amount of defocusing,etc.This paper introduced the off-axis laser cutting process,which works on the principle that the centerline of the laser beam is behind of the centerline of the auxiliary gas flow in the laser cutting feed direction,making a certain distance between them.In this paper,based on previous research,off-axis laser cutting process was used for cutting experiments on 2mm stainless steel plate,and mathematical models were established and multi-objective optimization of cutting quality parameters was performed by experimental data.Firstly,the cutting experiment was designed with the idea of controlled variable method to analyze the impact of technological parameters on the cutting quality.The plate was cut by varying the off-axis volume,cutting speed,auxiliary air pressure and laser current while the remaining technological parameters remain the same.The macroscopic effect of cutting was scored by expert scoring method,and the patterns of influence of each technological parameter was analyzed.Secondly,the results obtained from the previous step of the experiments were used to select a suitable range of technological parameters,and the response surface experiments were conducted to analyze the significance of each technological parameter and the interaction between each processing parameter using the slit width and the heat affected zone width as response values.Then,the response surface model,BP neural network model,and BAS-BP neural network model were trained according to the experimental data in the previous step,and after comparing the performance of the models,the BAS-BP neural network was selected to fit the expanded data to establish the cutting quality prediction model.Finally,two algorithms,BAS-BP and NSGA-Ⅱ,were combined to perform multi-objective optimization of the kerf width and thermal response zone width under different cutting technological parameters.The Pareto solution set was used to obtain optimal solutions for all process parameters at the first level,and the accuracy of the model was verified experimentally.The obtained experimental results could provide reference for off-axis laser cutting parameter setting,improved laser cutting quality and cutting efficiency in actual production,and increase the market competitiveness of enterprises.