Study On Injection Molding Technology With A Rapid Variotherm Mold For Products With Micro/nano-structured Surface

Micro-injection molding(μIM)technology can be used to form polymer parts with micro/nano characteristics,and temperature is the key factor affecting the quality of product.The performance of microinjection molding process can be improved effectively by adopting variotherm systems.However,the precision molding of micro/nano structure can not be completely realized by the current technology of variotherm systems,and the molding quality of micro/nano structure parts can not be guaranteed.This paper aims to improve the efficiency and quality of microinjection molding.The main research contents are as follows:1.Simulation of temperature field of rapid heat cycle molding(RHCM).A conjugate heat transfer model was established by finite element method to analyze the mold temperature distribution under different heating and cooling conditions during injection molding.The influence of the power of the thick film heater,heating area and the distance between the heater and the cavity on the temperature rise performance of the mold was studied,and the influence of the cooling mode on the temperature drop performance of the rapidly changing mold temperature system was discussed.2.Optimization of temperature distribution uniformity of the insert.The influence of transition layer on the temperature distribution uniformity of cavity surface was analyzed by FEM.The thermal conductivity of the transition layer is the most important factor affecting the temperature distribution of the cavity.The optimum structure of copper transition layer with 8mm heat insulation hole was determined.3.Thermal response of the insert.Thick film heating device was designed and manufactured.The thermal cycling efficiency and temperature uniformity of insert under various heating methods were evaluated,and the effects of various heating methods on the rapid thermal cycling of cavity were analyzed.4.Construction,application and evaluation of RHCM.The injection molding experiment platform of polymer surface micro/nano structure parts was built,and the technology of RHCM and transition layer was introduced.The surface microstructure and nanostructure of the polymer were formed,and the quality of the forming was tested and evaluated.There are overall 92 figures,6 tables and 69 references.