Development Of Multi-Function Precision Dispensing System Based On Vision

Adhesive bonding technology was an important part of micro device assembly. However, adhesive bonding technology was mostly in the manual operation level, the dispensing position accuracy and consistency of glue points were also difficult to be guaranteed. In the field of aeronautics and astronautics, there were strict requirements in adhesive bonding technology. This paper carried out experimental system equipment development and related technology research based on the application requirements which were test experiment of adhesive bonding of micro device and adhesive precision automatic sampling for small batch device.Designed and built a set of precision dispensing equipment which integrated jet dispensing and contact dispensing. Jet dispensing technology was suitable for high viscosity adhesive dispensing, contact dispensing technology was suitable for low viscosity adhesive dispensing. According to the functional requirements of the equipment, the equipment was divided into 4 modules, which included three axises variable speed control module, precision positioning and measurement module, jet dispensing and contact dispensing module, system control module. The main component of three axis variable speed linkage control module was three-dimensional control rod, quickly specified the location of the micro devices in the camera view with the aid of the visual positioning module, and then realized automatic sampling of specified location; precise positioning of glue points were achieved by the first dispensing glue point calibration method in precision positioning and measurement module, the camera was used to capture the image of the glue points, and the consistency of the glue points was evaluated at the same time; a high viscosity span of adhesive fluid dispensing function was realized in jet dispensing and contact dispensing module; the control of the whole system was completed through the interactive interface in the system control module.Aanalyzed the factors which affect the positioning accuracy of the glue points, included camera error, precision displacement platform accuracy, installation error caused by the exchange between the dispensing valve and contact dispensing barrel. Precision displacement platform accuracy, installation error caused by the exchange between the dispensing valve and contact dispensing barrel were two main factors affecting the positioning accuracy. In order to improve the positioning accuracy of the glue points, the compensation of the orthogonal error between axises was completed through the homogeneous matrix method based on the camera pixel calibration of the system, the compensation of installation error caused by the exchange between the dispensing valve and contact dispensing barrel was completed by the first glue point calibration method. The first dispensing glue points calibration method captured image by machine vision, obtained image location information through image processing, combined with the guide axis movement, calibration was completed, the positioning accuracy of the glue points was 10-60 ?m, meeting the requirements of the accuracy of micro device adhesive bonding. At the same time, dispensing position real-time tracking by the precision dispensing system nozzle and spray was realized and dispensing path was automatically formed.The experimental research and results analysis of dispensing were carried out after the equipment calibrated in this paper. The experiment included:minimum diameter glue points experiment, comparative results of dispensing experiments on different substrates, dispensing stability test, contact dispensing nozzle needle and substrate distance experiment, intermittent dispensing experiment and so on. Finally, the consistency of glue points in the precision dispensing system was studied.The approximate volume of glue points was obtained by the 3D profile measuring instrument of keyence. By comparing to the consistency of glue points of the two dimensional image method, found that the consistency of the glue drops obtained by the 3D profile measuring instrument was better.