OTEC optimizes automated finishing for 3D-printed earmolds and titanium ear pieces

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March 4, 2026 Applications 9840

Custom earmolds (otoplastics) are now often produced via additive manufacturing because geometries from an ear scan can be manufactured directly as one-off parts.

However, a downside of common 3D-printing processes remains the typical surface roughness of the raw parts. Especially for pieces that sit in the ear canal, this affects wearing comfort, hygiene, and appearance—and in many businesses still leads to manual rework.

A recent report from the OTEC Finishing Center describes how automated surface finishing in vibratory finishing processes can be further developed for earmolds and now also includes titanium ear pieces. The focus is on process adaptations for plastics such as acrylic and silicone, where conventional finishing steps often cause haze, a milky appearance, or loss of geometry. OTEC states that the goal is a surface quality that does not require additional hand polishing, and points to extensive test series to match process media and machine parameters in the CF series.

For titanium, the boundary conditions are different: material removal must remain minimal because the parts are delicate and the fit allows hardly any tolerance. According to the report, a specific mix of media and compounds was developed and the process control fine-tuned so that a mirror-like finish is possible without significantly altering the geometry. In parallel, repeatability was addressed so that results remain stable for printed and milled parts, and so that residues in channels or drill holes can be avoided.

In practice, the approach aims at a more industrialized process chain for 3D-printed ear pieces. If transparency in plastics and high gloss on titanium can be achieved in an automated way, the share of manual work drops while fit and surface integrity become easier to control. For manufacturers and users, this primarily means more predictable quality while maintaining individualized geometries.