Analysis of the flow behavior of thermally conductive thermosets during injection molding

随着当今电气设备功率的增加以及同时尺寸的减小，电子部件的热平衡已经成为一个挑战，因为越来越多的热量产生并且必须从系统中消散。一个具体的例子是对电机外壳散热的高要求，电机外壳具有高额定功率，并且必须在宽范围的环境温度下连续运行期间保持功能。相应的外壳由基于环氧树脂的热固性模塑化合物制成。除了必要的经典性能，如电绝缘能力，这些材料应用的主要障碍是很难预测部件中的局部导热率，因为对注塑过程中的流动行为和由此产生的填料取向的基本理解是，失踪了该研究项目的目的是使用一种创新的测量模具来研究与材料成分，生产过程和结构部件设计相关的方向相关热导率。这里的重点是更好地理解作为在模具填充期间的流动行为的结果的填料取向。为此，测量模具将根据门尼的概念，与熔体的流动行为可以在现实的边界条件下的第一次表征设计。通过使用集成在模具中的超声波和介电传感器，可以直接在工艺中观察固化过程，并且首次可以分析固化速度与工艺中的流动行为之间的关系。还计划使用磁性填料和测试仪直接在模具中确定填料方向。此外，计划使用磁性填料和特斯拉计直接在模具中确定填料方向。使用这种创新的测量技术，将在项目范围内从根本上研究材料和工艺对流动行为的影响。材料相关因素的重点在于填料的几何形状、填料含量和填料的导热性。工艺研究的重点是工艺热平衡和模塑料中的剪切效应。为此，对影响流动行为的主要因素，如单位温度、模具温度和注射速度等进行了基础性研究。

With the increasing power of today's electrical devices and simultaneously reduced size, the heat balance of electronic components has become a challenge, as more and more heat is generated and must be dissipated from the system. A concrete example of this is the high demand for heat dissipation for electric motor enclosures, which have a high power rating and must remain functional during continuous operation at a wide range of ambient temperatures. Corresponding enclosures are made of thermoset molding compounds based on epoxy resin. In addition to the necessary classic proper-ties, such as electrical insulation capability, the thermal conductivity of the thermoset insulation material is thus increasingly becoming the focus of users.A major obstacle for the application of these materials is that a prediction of the local thermal conductivity in the part is hard to make because the basic understanding of the flow behavior and the resulting filler orientation during injection molding is missing. The aim of the research project is to use an innovative measuring mold to investigate the direction-dependent thermal conductivity in relation to the material composition, production process and design of a structural part. The focus here is on a better under-standing of the filler orientation as a result of the flow behavior during mold filling. For this purpose, the measuring mold will be designed according to the Mooney concept, with which the flow behavior of the melt can be characterized under realistic boundary conditions for the first time. By using ultrasonic and dielectric sensors integrated in the mold, the curing process is observed directly in the process and, for the first time, it is possible to analyze the relationship between the curing speed and the flow behavior in the process. It is also planned to use magnetic fillers and a tes-lameter to determine the filler orientation directly in the mold.. In addition, it is planned to determine the filler orientation directly in the mold with the use of magnetic fillers and a teslameter. Using this innovative measuring technique, the material- and process-dependent influences on the flow behavior will be fundamentally investigated within the scope of the project. The focus of material-related factors lies on the filler geometry, filler content and ther-mal conductivity of the fillers. The process investigation focuses on the process heat balance and the shear effect in the molding compound. To that end, the main factors influencing the flow behavior, such as unit temperature, mold temperature and injec-tion speed, are to be fundamentally investigated.