The development of control system for large vacuum aluminum brazing furnace is introduced. The function of the control system is mainly temperature control and logic control, which requires a lot of control points, and each controlled object is related to each other. The core of the control system is programmable controller.
The CX programmer software is used to control and set up various protection functions of each mechanical system.
The PLC has the advantages of flexibility, convenience and easy maintenance.
The final commissioning results and the state of vacuum furnace after putting into use show that the control system can not only achieve the control objectives, but also ensure the equipment can run without fault for a long time.
Vacuum aluminum brazing is a welding method which is used to fill the gap of the base metal with liquid solder with lower melting point than base metal in vacuum heating state, and forms a solid combination. The process of filling the tiny gap of the base metal is completed by capillary suction.
From 1980s to 1990s, vacuum aluminum brazing technology and vacuum aluminum brazing equipment have been developed greatly in China. The mature process specification and technical requirements for aluminum brazing equipment for small aluminum plate fin heat exchanger are put forward.
In the early 21st century, due to the need of manufacturing technology of large aluminum plate fin heat exchanger, large vacuum aluminum brazing furnace was developed in China.
With the continuous improvement of industrial automation and the rapid development of computer technology, the level of automation control is also higher and higher, but the programmable logic control (PLC) is also being used as a reference As a control device, it can integrate the advantages of computer complete function, flexibility and universality, and the advantages of simple and easy to understand, easy to operate and cheap of relay system, and can adapt to industrial environment.
So PLC is used as the control core in the vacuum aluminum brazing furnace electrical control system, which has its obvious advantages. Programmable controller has been applied in most medium and small vacuum aluminum brazing furnaces. In the control system of large vacuum aluminum brazing furnace, there are many points controlled. Complex interlock protection is needed. Further development is needed on the original basis.
Commissioning and acceptance
After the vacuum brazing furnace is manufactured, the mechanical part is installed and the electrical control part is debugged at the user’s site.
Debugging is mainly to achieve through the whole control system and achieve the purpose of mechanical, electrical, gas, water linkage. The main contents of the control system debugging include configuring the parameters of various instruments (mainly temperature control meter and vacuum gauge) according to the actual use conditions,
checking the PLC program and configuration software of the upper computer in the process of cold debugging (no heating, testing vacuum index) and hot debugging (heating and vacuumizing), and setting the relevant parameters.
Finally, the equipment debugging is successful, and has passed the acceptance of vacuum index and temperature index, which fully meets the user’s requirements. Moreover, the operation is safe and the failure rate is very low, which fully illustrates the economy and rationality of the electrical control system developed with PLC as the control core.