Stapes bone
Potential for tiny implants:

The stapes bone, the smallest bone in the human body, manufactured by use of micro metal injection molding.

The "stapes bone" (lat. stapes) belongs to the auditory ossicles (hammer, anvil, stirrup) of the human middle ear. It transmits oscillations produced by sonic waves to the vestibule of the ear. However, this highly important part of the ear can also fail to function due to illnesses, for instance, which then requires the use of implants, for example made of titanium or titanium alloys.

The stapes bone is not only the smallest bone within the auditory ossicles, but also the smallest bone in the whole human body.
We have built the suitable mold for metal injection molding (MIM) and proved our skills with the manufacturing of metallic implants in cooperation with the Fraunhofer Institute for Manufacturing and Advanced Materials (IFAM) in Bremen.

Our molds for metal and plastic parts stand out due to a high level of precision and the smallest dimensions. Furthermore, medical technology, and especially the processing of biomaterials, is one of our most important business areas. We have based the design of the stapes bone on the size and form of the human original.

In order to produce the corresponding metal injection molds for such items, we are using completely new concepts, process chains and manufacturing procedures.
Steady development enables us to advance to smaller and smaller structures. The developed high precision mold was then manufactured by use of a special micro injection mold machine, both in stainless steel and titanium alloys. The part volume after injection molding amounts to 1.25 mm³.
After successful further processing (process steps necessary for MIM: Debinding and sintering), metallic parts with minimal dimensions of 280 µm and a weight of around 9 mg (stainless steel) and 5 mg (titanium) were produced.