Research On The Isothermal Extrusion And The Speed Control System For Large Extrusion Press

Large extrusion press as an important basis equipment in national defense industry is mainly used for the production of hard alloy extrusion deformation. In the extrusion process, the extrusion force, extrusion speed and quality of products are important considerations, product temperature directly affects the quality of products, and the research on speed control of extrusion press should consider the actual extrusion process. In order to improve the existing extrusion process, consider the unknown model of extrusion pressure, ensure product temperature to be relatively constant, increase the speed control accuracy in long-stroke extrusion process, the isothermal extrusion and extrusion speed control technology was studied in the article based on the125MN horizontal hydraulic press for the research object and the aluminum extruded rod for extrusion model. The main research contents are summarized as follows:(1) Based on the analysis of the basic structure and speed control system principle and composition of125MN extrusion press, each module of the speed control system mathematical model was established respectively, including the throttle system model, hydraulic-mechanical system model and the workpiece extrusion force model. The speed control system model was relatively complete.(2) For the extrusion force model, the aluminum rod extrusion was analyzed as an example. The changing rule of the extrusion force and the maximum temperature of the extrusion products with different speed were obtained on the basis of uniform extrusion. Analyzed the changes in the maximum temperature, the approach to get the speed curve was raised to ensure the temperature of the extruded product to be stable. The aluminum extruded rod was simulated using the obtained isothermal extrusion speed curve, and the simulation results were compared with the uniform extrusion. The results show that the temperature of extrusion products can be achieved stability using the changeable speed curve, while the speed function curve and extrusion force model were obtained for improving the extrusion process.(3) The established models of speed control system in the extrusion press were simulated; the control strategy was researched on the throttle system. The resulting extrusion speed function curve and extrusion force model were imported into the extruder solid model to form a complete model of speed control system. Striving to simulate real extrusion process, the reasonable control method and parameters were obtained; the simulation achieved a better effect.(4) The small model based on the functions of extruder was set up to simulate the speed control experiment of the actual extruder. Given isothermal extrusion speed curve to the system, the extrusion process was simulated with extrusion force, debugging parameters to obtain the accurate control result.