Nothing lasts forever – at least not in endoprosthetics – and even the highest quality implant has a limited life, mainly because of poor surface finish quality. OTEC Präzisionsfinish GmbH engineers have developed a range of applications for automated grinding and polishing processes to offer a new dimension in medical implant surface finishing.

Implant surface finish requirements depend on the field of application with quality determined by a highly accurate fit, a homogeneous surface, and pronounced or minimal edge rounding.

A perfect surface extends the life of replacement joints
Disc finishing machine from OTEC
Precise edges and a mirror finish is achieved using a process developed by OTEC

Consistent quality

OTEC engineers developed parameters for drag-finishing and disc-finishing processes to meet implant manufacturing requirements, supporting fast and economical surface finishing with consistent quality. Workpieces of varying shapes and weights can be deburred, ground, smoothed, and polished by placing workpieces loose or tiered in a rotating holder and moving them through customized abrasive media.

Bone plates

Bone plates usually require considerable edge rounding, and the surface should be as smooth and homogeneous as possible. Using a disc-finishing machine with different process parameters, traces of stamping and chip removal operations can be eliminated in a short time while producing a smooth, high-quality surface.

Ear molds

Otoplastic parts for hearing aids or hearing protectors are made from special plastics in a rapid manufacturing process that creates a rough surface. OTEC’s process quickly grinds ear molds in a disc-finishing machine. The machine delivers a smooth surface finish in a process that is gentle on the material – sensitive workpieces can be processed quickly and reliably without damage, cutting manual polishing processes where finish variations can occur.

Joint replacements

Hip or knee joints require a homogeneous, smooth, highly polished surface for all contact areas. OTEC engineers developed a dry process for drag finishing where workpieces are clamped in holders and dragged through the right grinding and polishing media in stages. Clamping the workpieces prevents them from damaging each other. The processing results depend on use of the ideal clamping angle, enabling 0.03µm Ra values.

Bone screws, dental implants

Bone screws and dental implants are made of stainless steel or titanium alloys and require unrounded, burr-free edges with a smooth, polished surface for easy insertion/removal. The smooth surface simplifies disinfection before insertion. Using a disc-finishing machine it is possible to create a smooth, highly polished surface without significant edge rounding. After this single-stage process, workpieces are light in color and have a pristine finish with Ra values as fine as 0.03µm.

Consultation to production

To determine the ideal combination of process parameters of each application, OTEC engineers work with customers to determine process choices, processing media compositions, rotation speed, processing time, and (in the case of drag finishing) the clamping angle.