| The multi-zone reflow oven is one of the indispensable steps in the surface assembly technology,It has a heating circuit inside which melts the solder pre-distributed on the circuit board to achieve a firm connection between the solder and the motherboard.If this process is not handled well,it will have a bad influence on the quality of printed circuit boards such as the phenomenon of weak welding,burning of components,monuments setting up and solder ball.In this paper,a temperature control system for SMT reflow oven is designed.PLC is used as a data acquisition and control platform which is achieved through its distributed I/O port to realize the temperature acquisition and the control,the uniform temperature distribution,the adjustment of the width of the guide rail and the speed of the chain.In addition,the real-time temperature monitoring and the setting of parameter are realized by the upper computer.Based on the design of a temperature control system for SMT reflow oven,a teaching simulation software based on the reflux temperature control system with strong functionality and good aesthetics is designed.It is applied to the teaching of higher vocational colleges and universities,which provides data information for the company's project "Electronic Manufacturing Industry Automation 4.0 Simulation Platform".This article first briefly introduces the background knowledge of reflow soldering,the current situation at home and abroad,the research content and innovation.Second,the paper introduces the principle of reflow soldering.Third,the PLC temperature control hardware system which include hardware architecture,heating system,signal acquisition system,hot air circulation system,motion control system and is designed.Fourth,on the basis of analyzing the temperature characteristics of the reflux oven,two kinds of different intelligent adaptive algorithms are compared.Then we decide and optimize the control algorithms.Fifth,the Simulink module in Matlab is used to compare the algorithms before and after optimization.Based on this,the PLC temperature control program is designed.Finally,the software system of the upper PC is designed.Through the combination of MFC and SQL database,a set of upper computer monitoring system with beautiful interface,concise and easy-to-understand function is designed.Based on this,a set of teaching virtual simulation system of reflow soldering which combine the hardware design is finally completed.The training virtual simulation system guides students to carry out independent learning and design by means of dragging sticks and flashing,which not only enriches the students' professional knowledge and improves their professional qualities,but also promotes students' learning efficiency and increases students' enthusiasm for learning. |
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