High precision micro components by the use of dynamically tempered injection molding

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The aim of the project is the investigation of the time-temperature-pressure conditions for amorphous thermoplastics for the realization of micro components with optimal surface shaping and minimized orientations and residual stresses, while achieving the highest possible dimensional accuracy over the entire component geometry at the same time. The novel process combination, the dynamically tempered injection stamping, combines the advantages of the dynamically tempered injection molding process and injection stamping. Dynamically tempered injection molding allows high surface aspect ratios while injection stamping allows highest dimensional stability over the entire constructional length. On the application side, it is the aim to optimize surface replication, the dimensional stability as well as to minimize residual stresses and orientations taking into account an economic cycle time.Basis of the research project is the knowledge about the various process-specific properties of the dynamically tempered injection molding and the injection stamping process. In the case of conventional dynamically tempered injection molding, volume shrinkage is compensated by melt injection taking place during the holding-pressure phase, resulting in limited dimensional tolerances due to inhomogeneous pressure distributions over the flow path. Injection stamping normally takes place at temperatures below the glass transition temperature of the material. Because of the fast solidification close to the edge of the part, this results in limitations in the shaping of fine surface structures. By combining both manufacturing processes, the advantages of the processes are not only to be used synergistically for the dynamically tempered injection stamping, but by means of the use of process-relevant material parameters and a temperature- and pressure-dependent process simulation, a maximum utilization of the component properties is to be achieved.