Design And Analysis Of Clamping Device For Injection Molding Machine Based On Medical SEBS

With the development of medical products production technology,in the medical injection molding equipment products precision,production efficiency,cost control and other aspects put forward a higher challenge.In this paper,the plastic injection molding machine is designed as a research object,against the thermoplastic elastomer SEBS widely used in medical products,discussed the design of the clamping device of injection molding machine,the finite element analysis of the whole and the template,the rigid-flexible coupling dynamics analysis of the clamping mechanism and the prediction of the shrinkage rate of the medical SEBS molding experiment.(1)The design of the clamping device is divided into the theoretical calculation of the toggle mechanism and the clean treatment which the medical injection molding machine must consider.The design of the toggle mechanism refers to the previous design experience,deduces and analyzes its force and motion characteristics,and makes a theoretical calculation of the stroke ratio and magnification ratio of the toggle mechanism and establishes its three-dimensional model.The cleaning treatment of the clamping device comprises the following steps:establishing a closed lubrication system to prevent the lubricating oil from leaking to cause the product to be polluted;moving template and the rod separation,the base of the slide to complete the dynamic template support and sliding,and in the rails on the installation of special protective cover,to avoid contamination of lubricants.(2)In the injection molding machine processing plastic products,the various components of the clamping device are subjected to dynamic impact loads,these dynamic impact load will lead to fatigue failure of mold clamping device.Based on the theory of mechanics,the finite element analysis software is used to analyze the static characteristics from the whole to the parts,to find out the stress concentration and deformation of the largest areas,check whether the strength to meet the requirements.The topology of the most dynamic dynamic template is optimized,and the weight of the template is realized under the premise of ensuring the strength,so as to achieve the goal of saving energy and reducing the cost of the injection molding machine and reducing the manufacturing cost.(3)Based on the virtual prototyping technology,the simulation servo motor is used to complete the opening and closing movement through the screw drive die,and the dynamic characteristics of the movement unit of the clamping device are analyzed.Fusion rigid-flexible coupling dynamics theory,let the smaller stiffness of toggle and rod flexible,the rigid and flexible coupling kinetics analysis was carried out,and the results were compared with the multi-rigid body dynamics,we will find that the rigid-flexible coupling dynamics analysis is more real reflection of the kinematic characteristics and dynamic characteristics of the clamping device.(4)CAE technique was used to simulate the shrinkage rate of medical SEBS products,and the simulation results were analyzed by the max-min difference and the variance analysis,and the optimal combination of process parameters was obtained.The optimum process parameters and volume shrinkage of SEBS(Kraton G 2705)were investigated by using the cylindrical specimen mold as the reference,and compared with the simulation results,the results are similar,indicating that the simulation method of the production of products and mold cavity size design has important reference significance.