MeKuMed - Production of hybrid pharmaceutical crimp caps using a combined thermoforming/reverse injection molding process with microform closure

As part of a research project (MeKuMed) we investigated the production of a pharmaceutical crimped cap using a combined thermoforming and reverse injection molding process as well as the insertion of microstructure.

The crimp caps consist of a metal and a plastic component that are used to keep the medication securely closed and sealed with the help of a rubber stopper. Until now, these crimp caps have been manufactured with a high level of machine and handling effort. It is not possible to achieve a media seal by joining the two parts together.

In this research project, an improved production of crimp caps in a single process chain was introduced and further investigated.
In this project, a 4-cavity mold was built that can produce flared caps with sealed metal and plastic caps using microstructures in a fully automated process. The aluminum caps were thermoformed and reverse-injected.

FEM simulations were used to optimize the thermoforming process. We used a two-dimensional, axisymmetric simulation model that was able to reproduce the results much more quickly than 3D simulations. The simulation results were used to optimize the process and the geometry of the metal cap as well as the pre-damage.
Therefore, we further investigated the production of the plastic caps with overmolding on microstructured metal caps using injection molding simulations in the Moldex3D software.
We then investigated how the process parameters affect the bond strength between the metal and the plastic caps. Both the experiments and the simulations showed that increasing the pressure and temperature leads to a higher filling of the microstructures and thus to a higher bond strength.

The project was carried out in collaboration with the Fraunhofer ILT, the IKV Institute at RWTH Aachen University, Pulsar Photonics, Siegfried Hofmann GmbH, KraussMaffei and Röchling Medical. The project was funded by the Federal Ministry of Education and Research (BMBF) under the contract number 03XP0291. If you have an exciting topic that you would like to investigate in more detail as part of a research project, please contact us - we look forward to working with you.