Optimization Design And Elastohydrodynamic Lubrication Analysis For Clamping Mechanism Of All Electric Injection Molding Machines

With the continuous development of injection molding technology and the continuous improvement of quality requirements to plastic parts, all-electric injection molding machine is becoming the future direction of the injection molding machine for small and medium, for its precision, high efficiency, energy saving and environmental protection. However, confronting the foreign mature all-electric injection molding machine products, our all-electric injection molding machine in research and development is relatively backward. Therefore, it is an important challenge to improve the performance of the injection molding machine and enhance market competitiveness.Mechanical parts of injection molding machine consist of clamping part and plastic injection parts, in which clamping part is the important part to ensure mold reliable locking and to achieve the opening and closing movement and ejecting products of the mold. The performance of clamping part directly determines the quality of molding products and efficiency of the injection molding machine. So it is important to improve the performance of clamping part.This paper firstly introduces the working principle of the toggle clamping mechanism, analyses the kinetic and dynamic characteristics of linkage mechanism based on motion mechanism, and deduces the mathematical expression of the main performance parameters, to understanding the functional relationship between the main performance parameters and the basic structural parameters of the mechanis.Then create a 3D modeling of the major components and their assembly, using the three-dimensional design software solidworks, based on the basic parameters of all-electric injection molding machine BE150 type clamping mechanism. Import the assembly model into dynamic simulation software ADAMS to create a virtual prototype. Impose constraints and apply the drive in ADAMS/View. Analysis the displacement, velocity and acceleration motion curves of Crosshead and he movable template centroid, through dynamic simulation.And then in ADAMS, select each variable of determining the mechanism motion state to parameterize, defined as the design variables. Create the parametric model, according to the geometric relationship of clamping mechanism opening and closing state. Parametric analyse the clamping mechanism modle:through design research, to analyze the impact sensitivity of each design variable to the objective function; through optimizing, to find the optimal mechanism design parameters within the constraints range.Finally, make an elastohydrodynamic lubrication analysis to the clamping ball screw. The formula of the thinnest lubricating oil film thickness is induced according to the Hamrock-Dowson expression and the contact parameters of ball screw. The influence of these parameters such as the rotating speed of screw shaft, the viscosiity of lubricating oil, the contact force helix angle and contact angle on the thinnest lubricant oil film thickness is analyzed by mathematical analysis software MATLAB. It can aim to improve the state of the ball screw lubrication.to make a judgment of lubricating state.