A mathematical model coupled with a numerical investigation of the evolving material properties due to thermal and flow effects and in particular the evolution of the crystallinity during the full microinjection molding cycle of poly (oxymethylene) POM is presented using a multi-scale approach. A parametric analysis is performed, including all the steps of the process using an asymmetrical stepped contracting part. The velocity and temperature fields are discussed. A parabolic distribution of the velocity across the part thickness, and a temperature rise in the thin zone toward the wall have been obtained. It is attributed to the viscous energy dissipation during the filling phase, but also to the involved characteristic times for the thermal behavior of the material. Depending on the molding conditions and the locations within the micro-part, different evolution of crystallization rates are obtained leading to at least three to five morphological layers, obtained in the same part configuration of a previously work, allowing a clear understanding of the process-material interaction.

中文翻译：

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微注射成型过程中聚甲醛结晶演变的模拟

使用多尺度方法提出了一个数学模型，结合对由于热和流动效应而演变的材料特性的数值研究，特别是在聚（甲醛）POM 的完整显微注射成型周期中结晶度的演变。执行参数分析，包括使用非对称阶梯式收缩部件的过程的所有步骤。讨论了速度和温度场。已经获得了零件厚度上速度的抛物线分布，以及薄区域朝向壁的温度升高。这归因于填充阶段的粘性能量耗散，但也归因于材料热行为的相关特征时间。根据成型条件和微型零件内的位置，