容栅式SMT钢网表面张力在线检测系统设计

SMT Steel mesh Surface tension on-line detection system by Capative sensor

摘要:

SMT贴片印刷中，钢网的平整度是影响贴片印刷质量的重要因素。钢网平整度是通过测量钢网四角和中间位置的表面张力确定。表面张力测量计分为指针式和数字式。目前尚无SMT钢网张力在线测量系统。设计一款基于容栅式位移传感器的表面张力检测系统，对于提高贴片印刷的质量，具有实际应用意义。容栅式位移传感器设计为定尺和动尺。表面张力引起动尺的微小位移，在定尺形成与位移关联的电容变化。GC7626控制器将定尺电容变化转成数字信号，精度为1N/cm。采用STM32F103C8T6微控制器为主控系统，STM32F103C8T6读取GC7626的张力数据，以及存储有钢网信息的RFID数据，并将数据通过蓝牙模块传输给上位机（手机）。上位机（手机）上设计有APP软件，对张力数据进行处理。系统已经成功应用工业生产中，实现了钢网张力的在线检测和智能化管理。

Abstract:

In SMT printing, the flatness of steel mesh is an important factor that affects the quality of SMT printing. The flatness of steel mesh is determined by measuring the surface tension of the four corners and the middle positions of the steel mesh. There are two kinds of surface tension measuring instruments: pointer type and digital type. At present, there is no on-line measuring system for tension of SMT steel mesh. The design of surface tension measuring system based on capacitance displacement sensor is of practical significance for improving the quality of SMT printing. The capacitance sensor is composed of static ruler and moving ruler. The tiny displacement of moving ruler caused by surface tension changing causes the capacitance changing between static ruler and moving ruler. The MCU （GC7626）changes the capacitance signal to digital signal，the accuracy is up to 1N/cm. In this paper, the STM32F103C8T6 is used master controller, the STM32F103C8T6 system reads the tension data from GC7626, and stores the information in RFID of SMT steel mesh. The STM32F103C8T6 system transmits the tension data and the information data of the steel mesh to the mobile phone(or PC) by the Bluetooth. APP is designed in the mobile phone(or PC) to process the tension data and realize the online detection of the tension of the steel grid. This system solves the core problem of intelligent management of steel grid production.The system has been successfully applied in industrial production to realize the on-line detection and intelligent management of the surface of the steel mesh.