Screw-free ultrasonic microinjection molding device for molten and plasticized polymer and molding method

Abstract

The invention discloses a screw-free ultrasonic microinjection molding device for a molten and plasticized polymer and a molding method. An injection part comprises an injection motor, a lead screw, an injection push plate and a connecting rod; an ultrasonic vibration system comprises an ultrasonic generator, an energy converter, an amplitude-change pole and a tool head; an injection module is provided with a plasticizing hole, a sub-runner and a mould cavity; a feeding system comprises a hopper and a support; and a mould closing and ejecting system comprises a mould closing hydraulic cylinder, an ejecting hydraulic cylinder, an upper mould fixing plate, a lower mould fixing plate and an ejector rod. A solid polymer is molten into a liquid under the action of frication thermogenesis and viscoelasticity thermogenesis applied into the polymer particle process through ultrasonic vibration, and meanwhile, ultrasonic waves play a cavitation role in the polymer liquid, so that the apparent viscosity is reduced, the phenomenon of short shot or insufficient filling in the machining process is overcome, the injection molding of a small plastic device can be well realized, the energy consumption is reduced, the difficulty in controlling the process is lowered, the economic efficiency of the device is increased, and the production cost is reduced.

Description

technical field [0001] The invention relates to a micro-injection molding device and method for a non-screw-screw ultrasonic melt-plasticized polymer, belonging to the field of micro-injection molding. Background technique [0002] With the development of MEMS technology and the large-scale application of tiny components, micro-injection molding technology has been paid more and more attention in recent years. The injection volume of micro polymer injection molding is small (generally only a few milligrams), the flow channel is shallow during the molding process, the cavity is small, the micro melt cools quickly during the filling process, the flow resistance is large, filling is difficult, and defects such as insufficient filling are prone to occur . People try to improve these defects by adjusting the production process by increasing the mold temperature, injection speed and injection pressure. However, these methods also bring problems such as longer molding cycle, high ...

AI Technical Summary

Problems solved by technology

The injection volume of micro polymer injection molding is small (generally only a few milligrams), the flow channel is shallow during the molding process, the cavity is small, the micro melt cools quickly during the filling process, the flow resistance is large, filling is difficult, and defects such as insufficient filling are prone to occur

People try to improve these defects by adjusting the production process by increasing the mold temperature, injection speed and injection pressure. However, these methods also bring problems such as longer molding cycle, high equipment cost, high energy consumption, and poor product quality. product economy

[0003] Some patents at home and abroad have adopted the method of assisting ultrasonic vibration on conventional injection molding machines, introducing ultrasonic waves into the injection process, such as adding ultrasonic waves to the mold [1～7] , runner [8～10] , plasticizing cavity [11] etc., although these methods have also achieved the effect of reducing viscosity, but due to the use of screw melt plasticization, there are problems such as the difficulty in manufacturing small screws, the difficulty of plasticizing polymer particles due to too small screws, and serious waste in the main channel, which are not suitable for The melt plasticization of micro-amount polymers is not conducive to the molding of micro-parts and the reduction of cost

The applicant conducted research on the ultrasonic plasticization process of polymers and applied for an ultrasonic plasticization rheological device [12] , but this device only has the function of ultrasonically plasticizing a large number of polymers, and does not have the function of using ultrasonic plasticization to plasticize a small amount of polymer and injection molding, which is different from the function and method of the device involved in this patent

José Fernando BAS FERRERO et al [13] Applied for ultrasonic vibration molding device, but the structure is too complicated, which is not conducive to the reduction of device cost and the integration of the whole machine

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