Research projekt MeKuMed - Hofmann Impulsgeber

Rendering eines Mehrfach-Spritzguss-Werkzeugs für Bördelkappen mit Handling

Research project MeKuMedShortened production chain for medical crimp caps

Turning five into three: Until now, there used to be five different individual manufacturing steps necessary for the production of medical crimp claps. As part of the state-funded “MeKuMed” research project, Hofmann has worked with project partners to develop a more efficient production in three steps only.

Decisive for this: The mould developed by Hofmann, including a handling system for time-saving and automated production.

Discover our project partners

What is a crimp cap?

A crimp cap closes ampoules filled with liquid with the matching rubber stopper for the medical sector in a sterile and airtight manner.

The cap is made of thin aluminium and plastic, which is partially detached at a pre-damaged area during use, thus exposing the rubber stopper. This can then be pierced with a needle for extracting the medication.

Previous production process

Five individual steps have been required in the conventional production of medical crimp caps:

Punching the blank (sheet metal cap) from a sheet metal coil
Forming the blank into an aluminium cap
Pre-damaging the aluminium cap
Injection moulding of the plastic component
Pushing the injection-moulded plastic component into the aluminium cap

This results in many different individual steps, which is associated with a high level of handling, cleaning and requirements for machines and moulds. As this product involves large quantities to be produced, the main aim of the MeKuMed project was to reduce the duration of cycles times.

Darstellung verkürzte Fertigungsketter von Bördelkappen

Previous production chain for the manufacturing of a medical crimped cap. © IKV Aachen.

From pilot mould to automated series mould

In the first stage of tool development, Hofmann created a new forming punch with different polishes and coatings for an existing test injection mould of the Institute for Plastics Development.
Following, a pilot tool with a single mould cavity was then designed, manufactured and further optimized to develop the combined process.
Using the resulting findings on the process and mould design, we then constructed and manufactured the final 4-cavity mould.

Spritzguss-Werkzeug mit Handling für Forschungsprojekt MeKuMed

Injection mould features

Cycle time of just 38 seconds
Direct, metallic sealing on the aluminium component
Forming of the sheet metal ends using a separate hydraulic cylinder or alternatively via the machine ejector
Complete article production
- without repositioning
- without turntable
- without index plate
- without turning plate

Handling System

The handling system consists of a table, which is used on the one hand for providing the blanks and on the other for depositing the finished parts. The blanks are arranged in four open-topped magazines.

The blanks are extracted using a gripper with lifting suction cup and then transferred to the mould using a vacuum.

The finished parts are removed after the injection moulding process using spring-loaded vacuum suction cups. The suction cups then place the crimp caps on a chute for prefabricated parts on the handling table.

Handling System für Bördelkappen Spritzguss-Werkzeug

New production chain

With the new production chain, the time and equipment requirements can be significantly reduced thanks to our injection moulding tool. This results in a more efficient production with higher quality and which is less prone to errors.

New manufacturing process

Microstructuring, pre-damaging and cutting out the blanks using a laser by project partner Fraunhofer ILT: circular pre-damaging allows the aluminium to be precisely removed. The rubber stopper can then be pierced with a needle.
Forming the metal blank into a crimped cap, followed by injection moulding the plastic component within the combined mould from Hofmann.

Traditionelle Fertigungskette für Bördelkappen

New production chain for manufacturing a medical crimped cap. © IKV Aachen.

Shorter cycle times

The complete injection moulding process with our tool has a minimal cycle time of just 38 seconds – for seven different individual steps. Our series mould therefore saves a lot of production time, effort and costs. In addition, the mould concept and process are scalable to an even higher numbers of cavities.

1. Inserting blends
2. Forming into a cup
3. Closing the mould
4. Injection moulding of the plastic component
5. Mould cooling
6. Opening the mould
7. Removal of the finished crimp caps via handling and simultaneous insertion of new sheet metal ends