Analysis Of Tool Wear And Development Of Compensation System In Short Electric Arc Milling

Short electric arc machining,as a low voltage and high current discharge machining technology,has been used in many fields,such as mine electromechanical and aerospace,and has achieved good processing results in turning.But due to its low voltage large current discharge characteristic,makes the interelectrode discharge energy is larger and the discharge area is relatively concentrated,the short arc milling and workpiece electrode wastage in poor surface quality of the two big problems,including large amount of electrode loss is affecting the geometrical precision of the workpiece and the main factors of material removal volume.The tool electrode loss is unavoidable in the field of electrical discharge machining,so it is necessary to investigate the electrode loss process and compensate the electrode loss.Focusing on the problem of large tool electrode loss in short arc milling,this paper explores the rule of tool electrode loss,and carries out the prediction of tool loss rate and the development of offline compensation software.In this paper,a single factor experiment is designed for the influence of different process parameters on the tool electrode loss,and the trend of tool loss in the process of short arc milling with different process parameters is analyzed under single variable.According to the single factor experimental results,the process parameters that have a greater influence on the tool electrode loss were selected,and the orthogonal experiment with four factors and four levels was designed.Through the experimental results,the influence of different process parameters on the electrode loss rate was obtained,and the experimental results were analyzed by means of range and variance analysis.In order to ensure the stability and accuracy of subsequent compensation studies,the theory of inter-pole electric field was studied in this paper,and the inter-pole electric field model was established by using the finite element software COMSOL to analyze the situation of inter-pole electric field,study the influence of electric field intensity on electrode loss,and predict the tool electrode loss morphology through the distribution of inter-pole electric field.The milling experiments with different machining distances were designed.The tool loss morphology,dimensional accuracy and inter-electrode current were studied.The tool electrode loss law in the machining process was analyzed.Then the influence of different tool wear period on the surface morphology was studied,and it was proved that different electrode wear period had a great influence on the whole machining process.In addition,the method of neural network prediction and off-line compensation is proposed to optimize the electrode wear of short arc milling tools.Firstly,the mathematical model of arc milling trajectory was established by calculus,and the fixed length compensation method was used to compensate the mathematical model of arc milling trajectory.Then,RBF neural network was used to establish a prediction model of relative tool loss rate based on the experimental results,and the prediction was verified.Then,the electrode loss compensation system was built through the secondary development function of UG,and the machining process was compensated by changing the NC code offline.Finally,by comparing the processing results before and after the compensation,the experiment proves that the geometric precision and processing efficiency of the workpiece are greatly improved after the tool loss rate prediction model and compensation software are used.