Analysis Of Large Scale Clamping Mechanism And Improvement Design Of Critical Structures

With the growth of applications of large-scale plastic products, the market demand for large-scale injection equipment increases rapidly. As the key components of the injection equipment, the clamping mechanism supports the mold, executes the opening and clamping action, and tops out plastic products. The performance of the clamping mechanism affects the quality of plastic products directly. This dissertation researched on the performance of the clamping mechanism and on the improvement designs of its critical parts. The kinematic and dynamic simulations of the clamping mechanism were carried out. A transitional structure of the crosshead head link and an optimization on toggle structure by improved artificial fish swarm algorithm were presented. Meanwhile, a new type of clamping mechanism with magnetic auxiliary was proposed.The main contents of the dissertation are as follows:In the first chapter, this dissertation first clarified the profile of the clamping mechanism from three perspectives: structure development, classification and the current research status. Then the state-of-art and existing problems of two typical clamping mechanisms, the five-point double-toggle type and the two-plate type, were discussed. After that, the research purpose and significance were proposed. Finally, the contents and framework of this thesis were given.In the second chapter, a review on the technical characteristics in the R&D of large-scale clamping mechanism is introduced. Then kinematic performance analysis of the 4000T clamping mechanism based on motion diagram is proposed. In order to reduce energy consumption during clamping work, a new type of clamping mechanism with magnetism-aided device is presented.In the third chapter, aiming at the fracture problem of the transitional structure of cross head link, structure analysis and fatigue analysis were carried out. Then a new design method with surface in the transitional structure on cross head link is propounded.In the fourth chapter, this dissertation made improvement of the AFSA by combining the advantages of TSA. With the link length of the toggle structure, toggle angle, oblique angle and maximum toggle angle as the variables, the improved AFSA was executed to optimize the stroke clamping amplification ratio and the power amplification ratio of the clamping mechanism, and to obtain the Pareto set.In the fifth chapter, according to the improved structure of cross head link and the optimized results of toggle structure, this dissertation established a digital prototype of the clamping mechanism based on assembly unit, and then conducted the dynamic and static simulation. Meanwhile, a preliminary analysis on the magnetic field strength of the magnetic device was carried on by using FEM.In the sixth chapter, the further research is put forward after summarizing all the achievements of this dissertation.