Study On Microstructure Injection Molding Quality Under Ultrasonic External Field

With the development of MEMS technology,plastic parts with microstructures havegained broader development space in the fields of biomedicine,detection technology,environmental engineering and so on.Obtaining large quantities of microstructured plastic parts through the micro-injection molding process has the advantages of stable performance,low cost,and short cycle time.When the microstructure has a rectangular cross-sectional feature and the depth and width are relatively large,it will cause problems such as low replication accuracy of the microstructure and excessively large rounded corners of the right-angle root opening.Ultrasonic technology is introduced into the micro-injection molding process,which improves the fluidity of the polymer melt through ultrasonic vibration and improves the microstructure replication accuracy.This article takes the microstructure of plastic parts as an object to study the influence of ultrasonic vibration on its forming quality.Firstly,the research results of micro injection molding at home and abroad are summarized.The focus is on the flow behavior of polymer melt at the micro scale.Unlike conventional injection molding,the effects of wall slip and viscous dissipation will greatly affect the polymer at the micro scale The melt flow ultimately affects the replication accuracy of the microstructure of the plastic part.The application of ultrasonic waves and ultrasonic waves in micro-injection molding is discussed.The differences of ultrasonic high-frequency vibration on polymer melts is studied,which changed the molecular orientation of polymers,reduced the melt viscosity of polymers,and improved the mold filling of polymer melts Flow and replication accuracy.The application of ultrasound in the process of micro-injection was studied,and the effects of different application sites and the setting of ultrasound parameters on the quality of the microstructure are analyzed.Secondly,use Moldflow mold flow analysis software to simulate the fullfilling process of the polymer in the cavity,and process the ultrasonic vibrator by Ansys simulation software.A single-factor experiment is carried out by fixing the microstructure nickel plate to the fixed mold insert.The injection molding experiment is carried out with the injecting speed,injecting pressure,melting temperature,ultrasonic power and ultrasonic action duration as parameters.Under the condition of applying ultrasonic vibration,analyze the changes of varioust injection parameters and ultrasonic parameters on the replication of the microstructure,study the relation between different parameter settings and the moldingquality of the microstructure in horizontal and vertical positions of the plastic part,in order to obtain the best injection molding parameters combination.Finally,the micro-groove protrusions are processed on the end face of the ultrasonic vibrator horn by electrochemical machining,so that the microstructure and the ultrasonic vibrator are integrated,and the ultrasonic assisted micro-injection molding experiment is carried out.The fullfilling effect of the polymer melt in the horizontal and vertical directions of the microstructure under the action of ultrasound is studied,and the time-different carve of the opening gap of the micro groove of the plastic part during the filling process is drawn.Effect on the degree of microstructure replication.