Research On Visual Positioning Technology Of Micro Droplet Jet System

Inkjet printing technology is widely used,and the demand is constantly evolving toward high efficiency,high precision,and intelligence.Based on the original printing platform,this paper introduces a vision system to solve the positioning problem of the initial position,to meet the accuracy and efficiency requirements of pattern device printing and improve its adaptive adjustment ability to the working environment,without independent fixture design.In this paper,based on the droplet jetting system,the visual positioning technology is developed to realize the automatic positioning of the workpiece,the extraction of the jet printing contour and the automatic jet printing of the platform.The main research contents of this paper are as follows:(1)Analyze the overall requirements of the droplet ejection system and design the visual positioning system.First,discuss the performance parameters of the hardware equipment and the selection scheme,and then carry out the software design,and select the secondary distributed control structure of the upper and lower computers.Among them,the industrial computer is the upper computer,which is responsible for the management system and image processing,and the motion control card and the image capture card are the lower computers,which are responsible for controlling the motion system and image acquisition functions.(2)Calibrate the visual positioning system.Analyze the camera model,use Zhang’s calibration method to calibrate the camera,and obtain the camera’s internal parameters and distortion parameters.The conversion relationship between the image coordinate system and the world coordinate system is established,and the nozzle offset calibration is performed by the method of droplet coordinate comparison.(3)Image processing of the visual positioning system.Firstly,image preprocessing is used to reduce noise by filtering algorithm,and then the contour area is obtained by the method of threshold segmentation,and then the rectangular contour is obtained by filtering the information such as contour perimeter and area.The method of using two rectangles to obtain the center lines of their adjacent sides obtains the coordinate of the contour points in an orderly arrangement,and through optimization and improvement of some existing image defects,the resulting print track is more accurate and reliable.(4)Realization and testing of visual positioning in the printing system.The first is to verify the reliability of the repeat positioning accuracy of the printing system;then the printing process is explained,and the influence of the printing height on the printing quality is discussed,and the appropriate printing height is found to stabilize the final morphology and diameter of the droplets.And the diameter and morphology of the 4×4array droplets are measured by a digital microscope,so as to verify the consistency and stability of the printing system;finally,through the dot matrix and line segment printing of the device,and the measurement results are analyzed,the error Less than 0.012 mm,to verify the feasibility and reliability of the visual positioning system in the printing system.