Research On Ultrasonic Assisted Injection Molding Of Microstructural Plastic Parts

The improvement of micro-electromechanical system technology has made plastic parts with micro-size characteristic structures more and more widely used in many fields such as optics,clinical medicine,and micromechanics.When injection molding parts with micro-dimensional features,due to the existence of micro-scale effects,it is difficult for the melt to be fully filled with micro-dimensional features,which has a great impact on the molding effect and use of the product.How to obtain high-precision parts with micro-dimensional characteristics has become a major problem in the field of micro-molding technology research.In this paper,taking the microfluidic chip as the research object,taking the opening width of the micro trench of the injection molding product as the index,and improving the quality of the microstructure injection molding product,the micro injection molding mold is combined with the ultrasonic vibration system,and the influence of ultrasonic and injection molding parameters of different power on the change of the opening width of the micro trench of the injection molding product is studied.Firstly,the structural design and processing of ultrasonic auxiliary injection molding molds are carried out.The ultrasonic oscillator luffing rod is matched with the mounting hole of the mold dynamic model cavity insert,so that the end face of the ultrasonic oscillator luminance rod is used as an integral part of the mold cavity,the ultrasonic vibration is introduced into the molding stage of the injection molding process,and the mechanical vibration of the ultrasonic wave is used to change the molecular orientation of the polymer melt,reduce the residual stress of the injection molded product,and reduce the viscosity of the polymer melt to improve the filling performance of the polymer melt at the microstructure of the mold cavity.Moldflow software was used to simulate the process of filling the mold cavity with polymer melt and to analyze the pressure distribution in the mold cavity.The amplitude of the ultrasonic oscillator amplitude rod at different power is measured by laser displacement measurement system.Secondly,ultrasonic assisted injection molding experiments with microstructures located in the model cavity were carried out.Using UV-LIGA technology on the surface of the nickel plate of the fixed mold insert,the cross-sectional size of 90μm high and 104μm wide micro-convexity was obtained,and the injection molding experiment was carried out with the variable parameters of polymer melt temperature,injection pressure,injection speed and ultrasonic power as the variable parameters,and according to the experimental results,the influence of ultrasonic parameters and injection molding parameters on the micro-groove molding quality of injection molding products in different positions and directions was analyzed.Finally,the ultrasonic assisted injection molding experiment of the microstructure located in the ultrasonic oscillator amplitude change rod end of the dynamic model cavity was carried out.Abaqus software was used to analyze the micro-raised structures with different aspect ratios of the end faces of the ultrasonic oscillator amplitude rod to provide a reference for the dimensional design of the actual micro-raised structures;the cross-sectional dimensions of 62mm high,the top width of 80mm,and the root width of 125mm were obtained by using EDM technology to study the injection pressure,injection speed,and injection pressure,injection speed,effect of polymer melt temperature and ultrasonic power on micro-groove molding quality in different directions at the center of the injection molded product.In this paper,the ultrasonic auxiliary injection molding experiments were carried out on the microstructure located in the fixed model cavity and the microstructure in the dynamic model cavity,and the influence of different ultrasonic power and injection molding parameters on the micro-groove molding quality in different positions and directions was systematically analyzed,which has certain practical reference value for improving the molding quality of microstructured injection molding products.