Design And Accomplishment Of The Control System Of A Superplastic Forming Machine Based On PAC

The superplasticity is a kind of property that some metals or alloys show the lowintensity and large elongation under certain conditions. It is because of this propertythat we can obtain some fine thin-walled parts with precise size, complicated shapeand symmetrical crystal particle. So the superplastic forming is a new way of few orno machining and precision forming. The technology of superplastic forming is moreand more used in the area of mechanic machining, especially in the aeronautic area.At present, the main control ways in the traditional automation field are relaycontrol, microcomputer control and PLC control. PC control system has a betterflexibility and can accomplish some more difficult functions. In addition, it has afriendlier HMI. But compared with the PLC control system, the PC control system isinferior in the ability of anti-interference, high in requirement of workingenvironment and long in designing and developing cycle of the control system. ThePLC control system and the relay control system have high reliability, strong abilityof anti-interference, low trouble rate, low requirement of working environment andconvenient maintenance. But the interoperability and the flexibility of PLC controlsystem and of the relay control system are not so well. Therefore, we adopt a controlprogram based on PAC in order to design a control system with excellent technologyand performance for the control object of the superplastic forming. PAC controlsystem combines the advantages of PLC control system and of PC control system.This is very important for the improving the whole technical performance of thecontrol object of superplastic forming. The author chooses the PAC control system asthe control project of superplastic forming machine, and finishes the design of thecontrol system of superplastic forming machine. In addition, he gives the design andthe realization of software and hardware programs basing on a superplastic formingmachine in ENSAM and the superplastic forming principles and theories. Thehardware design includes the selection of PLC, I/O allocation, PLC wiring design,digital input modules, analog input modules, digital output modules, analog outputmodules and other content; the software design includes multiple modules of PLCprogram design, multiple-screen human-machine interface design. At the same time,this article also elaborates the design process of the pneumatic control circuit, of the pressure PID regulator control theory, of the cooling control circuit and of thehydraulic control system, and ultimately achieves the realization of three controlmethods of the control system: debugging, manual and automatic. It plays a verygood role in the overall technical performance of the superplastic forming machinecontrol object.