Research On Optimization Of Automobile Varnish Film Spraying Process

As the main means of transportation for modern travel,the demand for automobiles is increasing,and the competitiveness between brands is increasing accordingly.People have higher and higher requirements for the visual appearance of automobiles.The varnish film layer is an important factor that affects the appearance of the car.A good varnish film layer makes the surface of the car smooth and bright.Otherwise,it will cause orange peel defects.Therefore,in order to further improve the surface morphology and use performance of the varnish film layer,the existing spraying methods and process parameters are optimized.At present,the spraying process route of the varnish film layer is mainly divided into two types,namely vertical reciprocating spraying and horizontal reciprocating spraying.The two spraying methods are matched with different production line modes.The vertical direction is matched with the continuous production line,and the production efficiency is high;while the horizontal direction is matched with the stop-and-go production line,the paint film sprayed has good performance,but the production efficiency is low.Therefore,the horizontal reciprocating spraying process is designed in the continuous pass-through production line,which not only ensures high production efficiency,but also ensures the high performance of the varnish film.First,according to the spraying trajectory spacing planning theory,the distance between two adjacent spraying trajectories is analyzed,and a paint mist fan with a diameter of 450 mm is sprayed.When the distance between the two spraying trajectories is 150 mm,the paint film surface is the most uniform.According to the principle of spraying trajectory planning,the horizontal spraying path is designed.The number of spraying direction changes of the horizontal spraying trajectory of one side door is 10 times,which is 4 times less than that of the vertical spraying trajectory;according to the principle of path planning,The horizontal spraying path is the best path.Secondly,for the vertical and horizontal spraying methods,the vertical spraying process parameters are analyzed,and the horizontal spraying process parameters are designed.For vertical spraying,there are 3 groups of main process parameters in the P0 area,namely: spraying flow 300 m L/min,380 m L/min,230 m L/min,forming air flow 320L/min,380L/min,300L/min,rotary cup Rotation speed 50000r/min,50000r/min,50000r/min,electrostatic voltage 70 k V,65 k V,30 k V,robot walking speed 480mm/s,1000mm/s,1000mm/s;the main process parameters in the P1 area are: spraying flow 300 m L/min,The forming air flow rate is 320L/min,the rotating cup speed is 50000r/min,the electrostatic voltage is 70 k V,and the robot walking speed is 480mm/s.For horizontal spraying,the spraying process parameters in the P0 and P1 areas adopt the same optimized values,namely spraying flow 330 m L/min,forming air flow 330L/min,rotating cup speed 50000r/min,electrostatic voltage 70 k V,robot walking speed 480mm/ min.Finally,visual inspection and instrumental measurement were used to analyze the surface orange peel morphology of the varnish film under the two spraying processes.The P0 area and P1 area of the car door were visually inspected for orange peel;the orange peel meter was used to measure the N1 and N3 values of the door P0 and P1 area,and the optimal spraying process was selected.The research results show that,by visual inspection,the surface morphology of orange peel under the horizontal process is better than that under the vertical process;the average value of the orange peel measured by the horizontal spraying process is smaller than that of the vertical spraying process,and the body P0 area N1,N3 The minimum decrease in the average value was 0.17 and 0.16;the maximum decrease in the average value of N1 and N3 was 0.90 and 0.81,respectively.The minimum decrease in the average value of N1 and N3 in the body P1 area are 0.65 and 0.62 respectively;the maximum decrease in the average value of N1 and N3 is 1.14 and 1.10 respectively.To sum up,the horizontal reciprocating spraying method is the best process method for the varnish film.The spraying process parameters in the P0 and P1 areas use the same value.The optimized process parameters are: spraying flow 330 m L/min,forming air flow 330L/min,Rotating cup speed 50000r/min,electrostatic voltage 70 k V,robot walking speed 480mm/s.