The development of control system for large vacuum aluminium brazing furnace is introduced. The main functions of the control system are temperature control and logical control, which require a large number of control points, and each controlled object is related to each other. The core of the control system is programmable logic controller.
The method of CX-Programmer software programming is used to control and set up various protection functions for each mechanical system. The programmable controller has the advantages of flexibility, convenience and easy maintenance. The final debugging results and the state of the vacuum furnace after putting into use show that the control system can not only achieve the control objectives, but also ensure the long-term fault-free operation of the equipment.
Vacuum aluminium brazing refers to the method of filling matrix metal gap with liquid filler metal with lower melting point than matrix metal under vacuum heating condition to form a solid bonding. The process of filling matrix metal gap is completed by capillary suction. From 1980s to 1990s, vacuum aluminium brazing technology and vacuum aluminium brazing equipment have been greatly developed in China. The technological regulations of mature small-sized aluminium plate-fin heat exchanger and the technical requirements for aluminium brazing equipment are put forward. At the beginning of the 21st century, due to the need of manufacturing process of large-scale aluminium plate-fin heat exchanger, large-scale vacuum aluminium brazing furnace has been successfully developed in China.
With the continuous improvement of industrial automation level and the rapid development of computer technology, the level of automation control is also getting higher and higher. However, as a control device, programmable logic control (PLC) can take the advantages of complete function, flexibility and versatility of computer and the advantages of relay system, such as simplicity, easy operation and low price. Points are integrated and can adapt to the industrial environment. So we think that the programmable controller has obvious advantages in the electric control system of vacuum aluminium brazing furnace as the control core. Programmable logic controller has been applied in most of the medium and small vacuum aluminium brazing furnaces. In the control system of large vacuum aluminium brazing furnaces, there are many points to be controlled, so complex chain protection needs to be set up, and further development should be made on the basis of the original one. The economy and rationality of the electric control system developed for the control core.