| Automobile spraying has a protective and decorative effect on car surface,the quality of automobile spraying has a direct impact on customer satisfaction and automobile sales.How to improve the quality of automobile spraying has become a subject of extensive research by many scholars.Electrostatic atomizer with high speed rotating has been the development trend in automobile spraying industry.The atomization effect of electrostatic atomizer with high speed rotating and the spraying track planning of automobile surface become the main factors affecting the spraying quality of automobile surface.Traditional manual spraying is gradually replaced by automatic spraying technology.The automatic spraying trajectory planning inputs the three-dimensional parameters of the model waiting for spraying into the spraying trajectory planning system.The spraying trajectory planning system automatically generates the spraying trajectory of the spraying robot according to the input parameter information.Automatic spray trajectory planning represents significant progress in the automotive spraying industry.While dealing with complex automobile spraying surface,there are still some deficiencies in automatic spray trajectory planning.In this paper,the atomization mechanism and the development of off-line programming of spraying trajectory at home and abroad are analyzed.The effects of single factors such as central hole diameter,rotating limiting air inlet angle,rotating limiting air density and coating viscosity,as well as the two factors such as the central hole diameter and rotating limiting air inlet angle,rotating limiting air density and coating viscosity on the atomization effect of electrostatic atomizer with high speed rotating are explored.The factors of atomization are simulated with ANSYS software according to the control variable method,which provides a theoretical basis for selecting the optimum conditions of atomization.The spraying trajectory planning refers to the optimal overlap distance between adjacent spraying trajectories,which improve the spraying efficiency and quality of automobile spraying.The specific research contents are as follows:(1)The research of atomization mechanism.The atomization parameters were defined with atomization angle and particle size.The atomization effect of coatings was measured with the measurement principle of atomization angle and particle size.According to the National Automotive spraying industry standard,a suitable spraying coating for automotive surface is selected.The atomization process of liquid and the formation process of static droplets are adequately studied,which provides an important theoretical basis for the study of atomization mechanism.(2)Electrostatic coating.Electrostatic coating has become a trend of modern development.This part clarifies the principle and characteristics of electrostatic coating,studies the factors affecting the thickness of liquid film in the rotary cup,explores the relationship between the diameter of the central hole,the angle of the entrance of the rotating limiting air,the density of the rotating limiting air and the viscosity of the coating on the atomization effect of the coating,and uses FLUENT fluid simulation software to simulate the atomization model according to the control variable method,verifies the correctness of an effect on the atomization effect with the single factor and the two factors between the diameter of the central hole and the angle of the entrance of the rotating limiting air,the density of the rotating limiting air and the viscosity of the coating.It provides an important theoretical basis for selecting reasonable electrostatic atomization parameters and improving the spraying efficiency of automobiles.(3)Surface quality optimization of coating.Based on the study of three commonly used coating deposition models,the β-distribution function is selected,and the coating optimization model is established on the basis of the free-form surface coating deposition model.The optimal overlap distance between adjacent spraying paths is calculated by the single bubble sorting method,and the effect of spraying speed on the coating is further studied.The quality requirements of automobile spraying surface were achieved.In order to obtain the surface model information of spraying surface,referring to the typical Delaunay algorithm,the free surface is divided into triangles by MATLAB programming.According to the principle of irregular polygon workpiece slicing,the important position nodes of electrostatic atomizer with high speed rotating are obtained,and the spraying trajectory is generated.The problem of precision caused by automatic trajectory planning for complex surface spraying is solved,and the spraying quality of automobile spraying is improved.(4)System control and off-line programming.The control system of automobile spraying and electrostatic atomizer with high speed rotating is analyzed,and reasonable off-line programming software is selected to lay the foundation for automobile spraying with complex surface automatically. |
