Study On Prediction Model Of Femtosecond Laser Ablation Threshold

Femtosecond laser processing has been widely applied in many fields due to its small heat affected area and high machining accuracy,especially in the field of material processing.When the femtosecond laser is applied to machining,the most critical factor that influences the quality of femtosecond laser processing is the suitable ablation threshold.Usually,the method of obtaining ablation threshold is determined by physical process experiment.This method not only consumes a lot of manpower,material and financial resources,but also has poor reusability of the data,and it is more difficult to obtain the inherent law of laser and material.To solve this problem,based on the analysis of the theory of femtosecond laser machining at home and abroad and the theoretical research based on case-based reasoning,the prediction of the ablation threshold of femtosecond laser is studied by numerical calculation and case-based reasoning,and the specific work is as follows.First,in order to predict the ablation threshold by numerical calculation,based on the analysis of the existing mechanism model of the femtosecond laser and material,the idea of replacing the energy density with the temperature instead of the energy density is proposed.Secondly,combining the temperature threshold with the two temperature model commonly used in the femtosecond laser machining simulation,a method is proposed to predict the ablation threshold of the femtosecond laser by numerical calculation,and the feasibility of the method is verified by the example of the prediction of the ablation threshold of SiC.Thirdly,on the basis of the relevant research results at home and abroad,the materials and laser parameters related to the femtosecond laser ablation threshold are summarized,and an example based method for the prediction of the femtosecond laser ablation threshold is proposed.According to the actual situation,an improved K-nearest neighbor algorithm based on example based femtosecond laser ablation threshold prediction method is improved,and an attribute distance weighted K-nearest neighbor algorithm is proposed.Finally,in order to support the application of attribute distance weighted K-nearest neighbor algorithm,a case library of femtosecond laser processing is established.We use C#,MATLAB,SQL Server and other tools and platforms to develop the system prototype.