With the rapid development of 3D printing and biocompatible materials industry, titanium customized hearing aids have become an important innovation in the field of hearing. In addition to providing a more reliable and comfortable wearing experience for the hearing impaired, it has also realized a comprehensive upgrade in terms of precision, durability and health and safety. The following is a step-by-step introduction to the manufacturing process and maintenance of titanium customized hearing aids.
1Hearing aid shell design
In the personalized customization of hearing aids, the “shape” directly determines the fit of the hearing aid shell with the ear canal, which is crucial to the subsequent wearing comfort and acoustic effect.
1.1 Earmold Sampling
(1) Auricular mold sampling staff use professional auricular mold sampling material (usually silicone) to cast an auricular mold in the ear canal of the hearing impaired person, trying to capture the shape and curved structure of the ear canal. Before sampling, it is necessary to check the health condition of the external ear canal to exclude inflammation and abnormalities of the ear canal.
(2) Preliminary cutting and shaping After the ear mold is cured, the ear mold is preliminarily cut and shaped or trimmed according to the condition of the user’s ear canal. Excess parts are removed for subsequent digital scanning.
(3) Scanning of ear mold Using 3D impression scanner to scan the processed ear mold with high precision. The data is imported into 3D software for shape design and optimization to ensure a high degree of fit with the anatomical structure.
Earmould Scanner
1.2 Direct scanning and shape taking using a scanner
(1) The 3D ear canal scanner uses endoscopic or laser scanning equipment to directly acquire three-dimensional data of the ear canal without the need for a physical ear mold. Compared with traditional methods, it can reduce the error, shorten the operation cycle, and view the scanning results in real time.
Ear Canal Scanner
(2) The 3D modeling software imports the real-time output 3D data of the ear canal into the modeling software, and the shell design is carried out by combining the needs of the hearing-impaired people (e.g., the type of deafness and the degree of hearing loss), so as to achieve a balance between accuracy and comfort.
1.3 Ear canal CT shape taking
(1) Medical imaging 3D reconstruction Suitable for special cases such as abnormal ear canal and postoperative reconstruction. Through medical imaging such as CT or MRI, three-dimensional data reconstruction is performed to restore the anatomical details of the ear canal to the greatest extent possible. It is more helpful to detect ear canal lesions, narrowing, deformities, etc., and can be targeted for correction during shell design.
CT scan of the ear canal
(2) Shell design and optimization: Import the reconstructed 3D model into CAD/CAM software, and design the shell according to the structural characteristics of the ear canal and the acoustic requirements of the hearing aid. Optimize wearing comfort and sealing, as far as possible to avoid the generation of acoustic feedback (whistling).
2 hearing aid shell 3D printing
2.1 Molding method: selective laser melting (SLM) Working principle: SLM technology uses a high-energy laser beam to selectively melt metal powder layer by layer on a bed of metal powder, fused into a dense entity, and with the help of the platform layer by layer down to ultimately form three-dimensional parts.
Advantages: Can achieve high-precision, high-complexity structures without the use of molds; Adaptable to a wide range of metal powders, including biocompatible titanium; Short production cycles and iterative flexibility.
Selective Laser Sintering
2.2 Printing material: medical titanium metal powder
Biocompatible medical titanium metal is corrosion-resistant, not easy to produce chemical reactions with body fluids, reducing the risk of allergies and rejection. Excellent mechanical properties titanium alloy has a high specific strength, the shell can conform to the ear canal curvature but also durable, not easy to deform or break. Lightweight titanium alloy density is relatively low, so that the hearing aid in the wear almost no burden feeling.
2.3 3D Metal Printer
(1) Main Components Powder Spreader: spread titanium powder evenly on the molding platform; Laser Scanner: accurately control the laser alignment and heat input according to the slicing data; Molding Platform: can realize the layered descent for layer-by-layer molding.
(2) Process monitoring real-time monitoring of powder thickness, laser power, internal temperature and other parameters to ensure stable print quality.
2.4 Printing process
(1) Model slicing processing The 3D CAD model is cut into a number of layers to generate X-Y plane geometry information and laser scanning path.
(2) layer by layer sintering 3D metal printer powder spreader first layer of powder, laser scanner according to the set movement instructions in the powder on the local sintering; molding platform down a layer, and then lay a new layer of powder, and so on, until the sintering of the complete hearing aid shell.
(3) The overall molding is completed to remove the excess unsintered powder for recycling; the molded shell for the initial inspection to ensure structural integrity without defects.
(4) Post-processingAfter the hearing aid shell has been printed, it needs to pass through a fully automated polishing process in order to meet the requirements of comfort and aesthetics.
3 Hearing aid testing
In order to evaluate and optimize the working performance of hearing aids in the actual use environment, professional acoustic equipment and hearing test instruments are usually required for further adjustment and confirmation.
3.1 Sound field evaluation
Passive sound field with the help of loudspeaker unit and adjustment bracket, test the wearer’s hearing experience under different volume and frequency; commonly used in basic assessment.
passive sound field
The active sound field simulates more complex sound environments, such as background noise or echoes, to evaluate hearing aid noise reduction and speech recognition performance.
active sound field
3.2 Audiometric equipment
Audiometer
Determine the individual’s sensitivity to various frequencies of sound waves, clarify the type and degree of hearing loss, and provide reference for the adjustment of hearing aids.
audiometer
The True Ear Analyzer measures the actual sound pressure level output from the hearing aid through a miniature microphone in the ear canal, allowing for precise tuning and improved wearing comfort.
Real Ear Analyzer
Coupling chamber
Accurately test the power and amplification of different hearing aids to provide a basis for selecting appropriate amplification parameters.
Coupling chamber
3.3 Audiometric Room and Pure Tone Audiometry Impedance Meter
Audiometric Room
With excellent sound insulation, it can accurately assess the actual hearing condition of the hearing impaired person and assist in fitting and effect testing.
audiological laboratory
Pure Tone Audiometry Acoustic Impedance Meter is used for hearing diagnosis of patients with hearing loss and helps professionals to develop a reasonable hearing compensation program.
Pure tone audiometry acoustic impedance meter
4 Hearing aid accessories
4.1 Magnetic steel needle brush
Cleaning earwax, battery installation, volume fine-tuning all-in-one; small and portable, providing convenience for daily maintenance.
Magnetic Steel Pin Brush
4.2 Dry box
Prevent the hearing aid from moisture, supplemented by drying cakes and other water vapor can be adsorbed; long-term to keep the internal circuit and metal parts dry and stable.
dry box
4.3 Soft earplugs
Available in a variety of sizes to better seal the ear canal, reduce whistling, improve wearing stability and optimize acoustics.
soft earplug
4.4 Anti-static tweezers Prevent static electricity from damaging the internal circuitry of the hearing aid when replacing precision components or batteries.
Antistatic Tweezers
4.5 Battery
Provide stable power supply for hearing aids; need to be replaced regularly according to power consumption and usage habits to ensure sound quality and multi-functional applications. Rechargeable batteries are under development at a later stage.
button cell
5 Hearing aid cleaning and maintenance
Hearing aids are often in contact with the ear canal, earwax, sweat and grease are easy to block the sound hole, attached to the shell, if not cleaned in time, it will affect the sound quality and equipment life.
5.1 Hearing aid cleaning program
Basic cleaning with a dry, soft cloth to gently wipe away surface dirt; use small brushes, ferromagnetic steel needle brushes, etc. to clean up the periphery of the sound hole and crevices, to ensure that the sound channel is smooth.
Deep Cleaning Cleaning Line and Air Hole Pass Rod: Apply to the customized machine ventilation holes and sound guide tubes in the dirt dredging; earwax suction remover: use instant suction to remove stubborn cerumen and foreign objects, to avoid secondary damage to the ear canal and the internal precision components of the hearing aid.
Earwax Remover
Cleaning aids dry wipes: surface moisture or grease wiping of the housing and components; magnet steel pin brushes: installation of batteries, volume fine-tuning and small crevice cleaning multi-functional all-in-one.
Magnetic Steel Pin Brush
5.2 Hearing aid moisture program
Dry box and dry cake
When the hearing aid is not worn at night, put it into the drying box and use the drying cake to absorb excess moisture; check and replace the drying cake frequently to prevent the humid environment from accelerating the oxidation of metal parts or producing mold.
Drying kit
Includes drying box, drying cake, cleaning balloon, LCD meter, dry wipes, magnet and steel needle brush, etc. A complete set of tools for more comprehensive maintenance.
6 Conclusion
The rise of titanium customized hearing aids not only stems from the fusion of material science and 3D printing technology, but also from the in-depth insight into the core needs of the hearing impaired. From the precise measurement of the ear canal taking shape, to the SLM metal molding and post-surface treatment, to the final professional inspection and maintenance, every step reflects the rigor of contemporary industrial and medical engineering.
As a cutting-edge hearing compensation device, titanium customized hearing aids are biologically safe, highly durable, and comfortable to wear, and at the same time, they can also be accurately matched to individual hearing with professional equipment such as real ear analyzers and audiometers. In the future, with the popularization of smarter AI algorithms and wearable sensors, hearing aids may further realize real-time environment recognition, automatic noise reduction and remote commissioning, bringing smarter and higher quality overall hearing solutions for the majority of people with hearing impairment. Let everyone be able to listen at a higher level and receive the world’s splendor and warmth again.
