Study On The System Pressure Characteristics Of ASJ And Its Control Technology

As one of the fast-growing nontraditional machining technique, abrasive water jet(AWJ) technology is very attractive and has a continuously development process. AWJ, which is always named as injection abrasive water jet, have been mature in actual industrial applications after rapid growth of recent years. Abrasive suspension jet(ASJ) which is called as pre-mixed abrasive water jet, is a two-phase jet which only contains water and abrasive particles. In the same pressure or power conditions, ASJ has a stronger cutting ability than AWJ, and abrasive particles can get more energy in the ASJ system, and it is more convergent than AWJ. But the development speed of it is relatively slow, due to the difficult implementation of the ASJ. In this study, it researches on the basic theory and application technology of ASJ, in an effort to further explorer the application and development in the field of ASJ and related technical problems.System working pressure is the most important parameter in the ASJ system, which is also the key point of the researching on this dissertation. In this dissertation, the boosting and decompression process of the ASJ system are described by two mathematical models theoretically. The decompression time of the ASJ system, the target maximum pressure and the time consumption of the boosting process, which are influence seriously on the machining efficiency, can also be predicted well. Combining the experiment and simulation research method, the correctness of these relevant theoretical models are verified.The ASJ system which is used as an experimental system can realize the maximum working pressure of 80 MPa. And the automatic pressure control system has been realized based on PID control algorithm with an ideal form. An overall analysis of related parameters in this pressure control system has been given out in the study. With this PID control system, it achieves the control stability and fast regulation of the system pressure. During the boosting process, it can greatly shorten the consumption time for the system to stable to the maximum working pressure. It is helpful to improve the working efficiency and to promote the industrial application of this technology.According to the theory study of the ASJ system pressure characteristics and basis of the research on the PID control system, an online monitoring system used to monitor the working pressure and flow rate of the ASJ system are built up based on the automatic pressure control system. The ASJ system running state can be obtained through the analysis of the monitoring data. It does an exploratory study for improving the industrial application of the ASJ technology. In particular, abrasive concentration and wear condition of a nozzle are really effected the working pressure and flow rate of the ASJ system. All these effects are discussed and analyzed in this dissertation. And online monitoring methods for abrasive concentration of the abrasive water jet and the changes of nozzle diameter affected by the wear are built up.