电热变模温注塑模具加热系统优化研究

Study on the Optimization of Heating System of Electrothermal Variable Mold Temperature Injection Mold

在电热快速变模温注塑成型中,加热系统的优劣直接影响产品质量。而加热后模具温度的均匀性是衡量加热系统的主要指标之一,它主要与模具结构、加热棒的热流密度有关。在不改变模具结构情况下,仅通过改变各加热棒的热流密度值来提高加热后模具温度的均匀性进而达到优化加热系统的效果。首先建立了电热快速变模温注塑加热阶段的分析模型,对比了相同工艺条件下的实验结果,验证了模拟的正确性。当初始加热棒热流密度相同时,通过提高边缘加热棒的热流密度,改善了模具温度的均匀性。最后假设加热棒热流密度分别呈一次和二次函数分布,模拟分析得到当各加热棒热流密度不均匀时,为保证加热后模具温度均匀的各加热棒热流密度的取值准则。

In the process of electrothermal rapid variable temperature injection molding,the heating system had a great influence on the quality of the products.The uniformity of the mold temperature after heating was one of the main factors to measure the heating system,which was mainly related to the mould structure and the heat flux density of the heating rods.In this paper,without changing the die structure,the uniformity of the mold temperature was improved by changing the heat flux density of each heating rod to optimize the heating system.An analytical model was established for heating stage,and the simulation results were compared with the experimental results to verify the correctness of the model under the same process conditions.When the initial heating rod heat flux density was the same,the uniformity of the mold temperature was improved by increasing the heat flux density of the edge heating rods.Criteria for heat flux density of each heating rod was obtained by analyzing the nonuniformity of the mold temperature,when the heat flux density distribution of the heating rods was assumed to linear and quadratic functions,respectively.