| In molding process of resinous matrix composites by hot-pressing, many complicated physical and chemical changes exist and many intricate factors affect quality of the products. The most important element is temperature and pressure. Computer control system for its formation process is the guarantee of high quality of final products, and it also makes the whole process much reliable.The scheme of system is investigated. According to the diathermancy and the mechanical ability, the material of hot-pressing block is decided. The conduction oil as heat element and the circulating-oil cooling as cooling method are employed in temperature system by comparing several heat/cooling projects. The heat insulation material is selected.Using ANSYS simulate the distribution of temperate. The result shows that the temperature difference is 6.398"C.But the range is out of the demanding. Then I am analysis the impact on the distribution of temperate. First the thermal loss between the mould and surrounding environments is explained and the solution is given. Secondly, considering diffusion rate of material, the analysis of this is given. Finally, parallel two tubes in temperature lower region to solve the temperature distribution non-uniformity problem. The plan is carried on by ANSYS software to improve the temperature non-uniformity problem, through the changing of pipeline and then obtains the result that the temperature difference is 0.187℃, so satisfied the request.Then, the blue print of injection system of pressing, which includes hydraulic circle design, control scheme design, hardware choose, software structure design, is presented. The fact that the injection process is a process with high speed and high pressure requires the control valves and sensors to have rapid response and fine precision, sampling plate to has high Sampling frequency, control software to has better real-time property. In this paper, the principle of injection system of pressing machine based on electro-hydraulic proportional control is introduced in detail. In order to get a in-depth and visual understanding of the performance of real-time controlled injection system, MTALB and its SIMULINK toolbox is used to build model, simulation and analyze for velocity control system and pressure control system of injection process. As result, response curves and dynamic characteristic parameters, which roundly represent the system performance, are obtained under various control signals during common PID control. |
