Otoplastics 3Dresyn OTO-HF – Hard & Flexible Resin (Shore D70)

Hard-flexible transparent photopolymer for otoplastics and hearing-related components (HF system)

Product description

3Dresyn OTO-HF is an advanced photopolymer engineered for the fabrication of clear, durable and hard-flexible ear molds and otoplastic components.

The material provides a unique balance between flexibility and rigidity, enabling comfortable yet mechanically resistant components with excellent optical clarity.

The formulation delivers high impact resistance and stable performance under repeated deformation, making it suitable for wearable audiology applications.

It is compatible with a wide range of SLA, DLP and LCD systems used in professional audiology and dental laboratories.

Application framework

Intended for professional use in vat photopolymerization (SLA, DLP and LCD) additive manufacturing for audiology and otoplastics workflows.

Final suitability of printed parts must be validated by the user according to the specific application, processing conditions and applicable regulatory requirements.

Typical applications

• Transparent ear molds and earmolds
• Custom ear shells and hearing aid housings
• Flexible-rigid in-ear components
• Wearable devices requiring clarity, comfort and durability

Material properties & test methods

Mechanical properties

• Tensile strength: <20 MPa (ISO 527-1 / ISO 527-2)
• Flexural strength: <20 MPa (ISO 178)
• Young’s modulus: <500 MPa (ISO 527)
• Elongation at break: <40% (ISO 527)
• Shore hardness: D70 (ISO 868)
• Impact resistance (Notched Izod): <85 J/m (ISO 180)

Thermal behaviour

• Stable performance under typical wearable conditions

Physical properties

• Optical behaviour: water-clear, high transparency, non-yellowing
• Water absorption: ultra-low (ULWA, hydrophobic)
• Shrinkage: very low (typical)
• Resolution capability: very high (features below 20 µm depending on process)
• Dimensional stability: high
• Structure: isotropic (minimizes light scattering and diffraction)

Functional performance characteristics

• Balanced hard-flexible behavior for comfort and durability
• High optical clarity for transparent components
• Excellent impact resistance and crack resistance
• Hydrophobic behavior with very low water absorption
• Suitable for thin-walled and complex geometries

Printing & processing guidelines

• Printing technologies: SLA, DLP and LCD
• Wavelength range: 385–405 nm
• Compatible with most commercial and professional systems when properly calibrated
• Optimized for high-resolution transparent parts
• Follow 3Dresyns IFU for exposure, washing and post-curing

Workflow recommendations

• Use validated cleaning and post-curing workflows to preserve optical clarity
• Optimize parameters to minimize haze and maximize transparency

Biocompatibility & quality framework

• Biocompatibility-related testing may be performed under controlled laboratory conditions
• Evaluation frameworks may include ISO 10993 methodologies
• Manufacturing aligned with ISO 13485 quality management systems
• Final biological performance depends on validated processing workflow

Important note

This material contains reactive components that may cause skin and eye irritation prior to full polymerization. Printed otoplastic components must undergo validated cleaning and post-curing workflows to ensure maximum achievable polymer conversion and reduction of residual extractables, leachables and byproducts. Final device qualification and regulatory compliance remain the responsibility of the legal manufacturer.

Testing & processing disclaimer

Material properties are measured on printed and post-processed specimens and may vary depending on printer type, printing parameters, build orientation, post-curing conditions and workflow validation. Reported values are indicative and provided for reference only.

Regulatory & legal notice

This material is supplied as a professional manufacturing material for audiology and otoplastics workflows and is not marketed as a finished medical device. The regulatory classification, conformity assessment and validation of any final device manufactured using this material remain the sole responsibility of the legal manufacturer in accordance with applicable regulations.

Why choose 3Dresyn® OTO-HF

• Hard-flexible balance for comfort and durability
• Excellent optical clarity and non-yellowing
• High impact resistance and dimensional stability
• Very low water absorption (ULWA)
• Very high resolution and low shrinkage
• Compatible with SLA/DLP/LCD systems

Document reference: TDS-OTO-HF-EN | Version: 1.0 | Last updated: March 2026