PLC-based PCBA Board Inspection And Sorting Production Line Control System Design

With the rapid development of science and technology in our country,Higher requirements for product quality together with increasing the output of circuit boards have been needed in many electronic manufacturing companies.After the circuit board and components are processed to form PCBA board,the production quality of the PCBA board needs to be tested.Due to the wide variety of components on the PCBA board,manual detection was used to ensure product quality,and then the unqualified PCBA board is sorted out by manual sorting operation.Manual detection not only has low efficiency and high cost,but also may cause problems such as missed detection and false detection.In particular,employees' direct contact with PCBA board cause components to be polluted,resulting in product quality degradation.In this thesis,a PLC-based PCBA board detection and sorting production line control system is designed based on the PCBA board manual detection and sorting production line of a manufacturing company.The system includes Siemens S7-1200 PLC,DELTA servo motor,computer,visual image processing equipment,etc.The system realizes the automatic production of PCBA board segmentation,detection and sorting,completely replaces the original manual operation production line,improves the production efficiency and quality of PCBA board,and completes the task requirements of the factory for the automatic production line.The main contents of this thesis include:(1)This thesis takes the manual inspection and sorting PCBA board production line of a manufacturing company as the research background,analyzes the technological process and functional requirements of PCBA board inspection and sorting,and designs the overall structure of the PCBA board inspection and sorting production line control system based on PLC.(2)According to the overall structure of the PCBA board detection and sorting production line control system based on PLC,the hardware of the production line system is selected and designed,including PLC and PLC expansion module,I/O address allocation,servo motor,visual image processing module,upper computer,network cable,RS485 communication cable,24 V DC power supply,relay,air switch,terminal.In addition,the EPLAN software is used to design the wiring diagram of the electrical control cabinet and assemble the required hardware equipment wiring.(3)The control scheme of PLC and DELTA servo motor is analyzed and compared.Because it is necessary for PLC to control three servo motors at the same time and PLC to monitor the data of servo driver in real time,traditional PLC pulse output control mode is abandoned.Instead,RS485 communication cable connection mode and Modbus-RTU communication protocol are adopted to complete PLC control of DELTA servo motor movement and data transmission between PLC and DELTA servo driver.(4)The image processing module and program for the detection of PCBA board are designed,including the selection of visual image processing module,the programming of image processing program,and the transmission of image processing data to the upper computer.The image processing part of PCBA board detection is completed,which can effectively and accurately detect the quality of PCBA board.Finally,the system is integrated,and the control system of the PCBA board detection and sorting production line is designed with Siemens S7-1200 PLC as the controller,the upper computer as the data processing core and the camera as the image processing equipment,and the wiring diagram of the electrical control cabinet is designed.The production line using the control system has been put into formal use,which not only meets the task requirements of PCBA board segmentation,inspection and sorting,but also exceeds the expected output of 1200 PCBA boards per hour.