Assembly molding presents an interesting approach to innovative product solutions. Here, individual components can be simultaneously positioned, affixed, and provided with a casing. However, while overmolding elements in the mold cavity with hot polymer melt, high mechanical loads occur on, in some cases, very sensitive components such as electronic devices. For the design of such systems, it is important to know these stresses, the influences on their quantities, and mathematical options for their prediction. In this article, a new measurement method for determining the forces acting on a small element in the cavity during the injection molding process in three dimensions is presented. Therefore, a new installation method for a force sensor was developed. The results in this article concentrate on force changes during one molding cycle. Our research shows that there are different mechanical load spectra in the different phases of the molding process. For example, the force component in flow direction on an element in the cavity is positive in the direction of the flow during filling. However, after the filling step, the force becomes negative due to the contraction of the injected material and results in a continuously increasing permanent force.

A deep understanding of the anisotropic, composite-, geometry-, and temperature-dependent coefficient of thermal expansion (CTE) of short-fiber-reinforced polymers is often needed in material development and at early stages of the design process of injection molded parts. Usually, the data available does not reflect the complex behavior and the knowledge about the influences and interactions are missing. This paper deals with a method for calculating the composite-, geometry-, and temperature-dependent anisotropic CTE of parts made from short-fiber reinforced polymers without respectively low preload to create an understanding of its origins and influential factors. Here, a good accordance between the measurements and calculations was achieved. POLYM.ENG. SCI., 55:2661SCI., 55: -2668SCI., 55: , 2015

A polymer's thermal conditions during processing in injection molding define the polymer's structure and with this the properties of the final part. Thus prediction of the temperature in the part during processing is of great interest here. One important value for calculating the temperature is the heat transfer coefficient (HTC), or the thermal contact resistance (TCR) between polymer and mold. Because of this, significant work has been done on this topic. This article gives an impression of the importance of HTC in injection molding and an overview over work conducted in measuring and calculating the HTC and the up to now known influences on it.

Due to the increasing number of electronics in several industrial sectors, especially in the automotive industry, there is a rising demand for flexible and adaptable electronic systems with high functional density and resilience. An efficient method for producing such parts is the encapsulation of metal inserts, for example lead frames, by means of assembly injection moulding. Often such parts are exposed to water and moist at the place of action. Thus, one major challenge is to provide electronics with enduring media tightness in a severe environment. The research work covered in this paper focuses on embossing surface structures in metal inserts for subsequent assembly injection moulding. The influence of geometrical parameters of the embossed profile on both the material flow and the accuracy of the created structure are investigated. For this purpose experimental as well as numerical results are presented. Furthermore, the performance of embossed inserts in subsequent assembly injection moulding is analysed.

Influence of micro formed edges of metal inserts on temperature cycling durability of tight polymer metal hybrids