Foundational Research On Superplastic Micro-extrusion Forming System And Control Technology

Superplastic micro-extrusion forming system is a kind of small machtronic system, which can produce small and micro parts with the micro grain superplastic material. This is based on the low strain and material of the superplastic material. The technology succeeds in lower metal forming temperature, stress and cost. In addition, the products have advantage in high mechanical performance and won't deform. Therefore it has a potential application in aviation and national defense area. The forming system equips with sensors for the technics parameter, detect and record the extrusion process, that would be used in the technics analysis and optimize. This provides a new method for the superplastic research.In this thesis, the whole configuration and the main parameters of the micro forming system are presented in details, and the measurement and control system for the temperature and speed is developed. All the research establishes a base for device design and superplastic forming study.Based on an industry computer and a multi function data acquisition card, Under the MATLAB/Simulink environment, The real-time measurement and control system for some key parameters such as temperature, velocity, pressure, displacement is developed using the rapid control prototyping technology. By this way, a complex control algorithm can be realized easily and decrease the development circle time.To meet a constant superplastic forming temperature, the temperature control system is designed through controlling the power of the resistance furnace by PWM with defferent controller. Aiming at the great time-delay character of the heating system, the performance of a traditional PID control algorithm is not satisfied. This paper develops a Smith predictor combined with PI and fuzzy PI control algorithm to the temperature control.Utilizing the step-servo motor to implement the drive of the superplastic micro-extrusion forming system, the control system is provided by register accessing can extend the control ability of a stepper motor with high divide of PCI-1710. Displacement open-loop control, close-loop control and open-loop speed control are realized.Test indicates the method is reliable and applicable.With the study on the superplastic micro-extrusion forming system and its measurement and control system, a feasible structure to this system is designed. The hardware of measurement and control system is builded;the real-time control program is developed. All of these have been provide the necessary preparative for the development of the superplastic micro-extrusion forming device.