Development Of Distributed Heating Stage Temperature Controller

With the development of social economy and technology,more and more small electronic products have entered thousands of households,but the speed of its replacement has accelerated,and the sales volume of discarded circuit boards has also increased year by year.Efficient recycling of precious metals and high-value small patch electronic components in waste circuit boards is the economic basis for recycling the electronic waste industry.If the extensive bulk crushing treatment is still used,it will not bring good economic benefits.Therefore,how to dismantle and recycle the waste circuit board chip electronic components has become the focus of the field of electronic waste disposal.To ensure the appearance and performance of the chip electronic components on the waste circuit board,it is the key to accurately control the temperature of the electronic components during the desoldering.This paper studies the automatic temperature control of the chip when the chip components of the discarded circuit board are unsoldered.Firstly,according to the characteristics of the disassembled device of the disassembled circuit board chip component,the distributed heating table mechanical structure is designed to achieve the effect of removing the chip point-to-point.In order to explain the rationality of the designed distributed heating stage,the basic theory of heat transfer is introduced,and the concept of finite element transient heat is introduced.Considering the external conditions such as heating medium to calculate the theoretical heating and holding power of a single heating station,combined with the finite element transient thermal analysis software ANSYS workbench,the distributed heating station is analyzed from the number,position and power of the control heating station.The biggest difference between the distributed heating stage and the ordinary heating stage is that there are coupled heat transfer phenomena in the nine aluminum block heating stages,and a method for solving the temperature control problem by manually adjusting the power is obtained.Secondly,the distributed control station temperature control algorithm is studied from the logic control.The theoretical basis of logic control is introduced-the generalized Boolean algebra.It shows how to use the semi-boolean scientific formal language to analyze the problems in the production control process,form a highly regular general logic diagram and a general logic expression,and realize the generalized control of the generalized control problem.After summarizing the law,the classic nine-point controller algorithm of the generalized Boolean algebra is obtained.Combined with the application requirements of the desoldered electronic components,the nine-point controller is reasonably improved to a multi-point controller.Delete the parameters that are not necessary in the control process,reduce the complexity of the temperature control system;increase the temperature control mark line,and increase the dynamic performance of the initial temperature rise of the system.Thirdly,the input and output variables of a single aluminum block heating stage are panbobrated,and the multi-point controller control rule is used to obtain a multi-point controller algorithm for a single aluminum block heating stage.Then,the distributed heat transfer relationship of the distributed heating station is also sub-bouling,and the number of heaters and the manual tuning power parameters are combined to obtain a coupled heat transfer baud algorithm suitable for distributed heating stations.In order to cooperate with the temperature control system,a single heating station and a distributed heating station can be switched to each other,and the two algorithms are further analyzed to obtain a distributed heating coupled heat transfer multi-point controller algorithm.Finally,a set of distributed heating station temperature control system combining software and hardware was designed.The hardware consists of master STC15W4K56S4 microcontroller,PT100 platinum resistance sensor,signal converter,thyristor and its optocoupler,485 communication chip MAX13487 and so on.The software sampling modular design idea is convenient for debugging,including RS485 of master and slave,serial communication module of lower computer and upper computer,temperature acquisition module,temperature control module,temperature input and display module.A single tin heating experiment was performed on a single electronic component,and the temperature control curve of the heating stage was recorded,which satisfies the initial temperature control design requirements.Compared with the disassembly rate of the common heating stage and the distributed heating stage under different pin patch components,the reliability of the distributed heating stage is verified.