Kinematic Analysis And Optimal Design For Double-toggle Clamping Mechanism Of Injection Molding Machine

Mechanical parts of the injection molding machine is composed of injection mechanismand clamping mechanism, the clamping mechanism is one of the most important parts, itsfunction is to guarantee the opening and closing movement and reliable locking of theforming mold and to eject the products. The system stiffness of the clamping mechanismaffects the quality of the products, the speed of the closing mold determines the efficiency ofthe machine, the clamping force determines the total energy consumption of the machine, andthe structure of the clamping mechanism also affect the cost of the machine. Hence, theclamping mechanism directly affects the overall performance and cost of injection moldingmachine.This paper firstly made a briefly introduction about the classification of the clampingmechanism and compared the advantages and disadvantages of different clampingmechanisms on the basis of fully understanding the current development situation of injectionmolding machine. Mainly introduced the working principle of the double-toggle five pointsclamping mechanism which is widely used in current domestic injection molding machine.Then deduced the right expressions of motion characteristics and mechanicalcharacteristics of the double-toggle clamping mechanism based on the existing optimizationdesign theories and methods of the toggle clamping mechanism, including the stroke of themoving platen and the clamping oil cylinder, the velocity and acceleration of the movingplaten, force ratio, clamping force and system stiffness, which are relative to the togglestructure parameters. Analyzed the multiple objective function in detail and chose areasonable method to unify the objective function. And then built up the optimizationmathematical model of the clamping mechanism according to the geometric constraints andperformance constraints condition, which providing theoretical basis for optimal design ofclamping mechanism.And then utilized the optimization toolbox and genetic algorithm optimization toolbox inMATLAB to optimize the structure parameters of the toggle mechanism and choose the betterresult, which made the structure of the clamping mechanism more reasonable and improvingthe movement characteristics and mechanical properties. In the meanwhile, established thegraphical user interface of the optimization program, which made the optimization operationmore convenient.And then established the virtual prototype model of the clamping mechanism in the ADAMS software with the help of virtual prototype technology, verified the correctness ofthe simulation model and simulated the movement of the clamping mechanism whichworking in the real working conditions, and then made a reasonable analysis according to thesimulation results.Finally, the movement curve of the clamping mechanism measured in the experimentwere compared with the simulation results, which is to verify the correctness of the virtualprototype model and the reliability of the simulation results further.