A NEW APPROACH FOR TEMPERATURE MEASUREMENT INSIDE AN INJECTION MOLDING TOOL

摘要

In the context of lightweight construction and miniaturization, especially in the automotive industry, direct encapsulation of electrical components in injection molded parts gains further in importance. In particular with regard to the processing of temperature sensitive semiconductor devices specific knowledge on the thermal load is required for product-life estimation. In consequence of its mounting points and mass-to-melt-ratio, standard temperature probes are suitable only to a limited extent for this kind of measurement. As this paper shows, semiconductor diodes are well capable of measuring the time-dependent temperature inside an injection molding tool because of their electrothermal properties. During the investigation probes with an edge length less than 200 μm have been mounted in the cavity of the tool. Due to the low heat capacity of the probe the temperature of the melt is unaffected by its presence and the thermal signal is registered with almost no delay. Using the method presented, the thermal load of directly encapsulated electrical devices can be measured. In particular the thermal degradation of semiconductors can be estimated.