Hearing Device Metal Shell Manufacturing with Sacrificial Elements

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Solution Overview

Problem

The existing methods for manufacturing metal shells for hearing devices face challenges in providing a readable identification label without occupying space and preventing grinding materials from entering the internal cavity, especially with harder materials like metals, and in ensuring the label does not damage functional components during assembly.

Innovation Solution

A method involving a 3D printing process using Selective Laser Sintering (SLS) to create a preform with a movable label and a protective element, where the label is attached externally and the protective element occupies the internal cavity, allowing for easy identification and preventing grinding materials from entering during surface smoothing, and both can be removed without interfering with the assembly of functional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an identification label is printed on the inside of the metal shell, then the shell can be identified, but the label occupies space and may damage functional components during assembly

Engineering Contradiction:
Improveidentification accuracyVSAvoidspace occupation
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The identification label is moved from the internal surface (2D plane inside the shell) to an external dimension (hanging outside the shell via chain), eliminating space occupation within the device while maintaining identification functionality

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The label is separated from the main shell body and connected via a chain, allowing it to hang externally without interfering with internal components during assembly

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If vibratory grinding is applied to smoothen the preform surface, then the surface quality is improved, but grinding materials enter the internal cavity and are difficult to remove

Engineering Contradiction:
Improvesurface smoothnessVSAvoidgrinding material contamination
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A protective element is placed inside the internal cavity before the vibratory grinding process to prevent grinding materials from entering, and then removed after grinding is complete

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The protective element is a temporary, disposable component used only during the grinding process, then discarded after serving its protective function

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If a plastic plug is pushed into the opening to protect the contour during tumbling, then the contour is protected, but this method is not applicable to harder materials like metals

Engineering Contradiction:
Improvecontour protectionVSAvoidmaterial compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

A protective element made of metal-compatible material is used temporarily during the tumbling process to protect the opening contour, then removed after the process

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The protective element's material properties are selected to be compatible with metal shells, unlike the plastic plugs used for plastic shells, demonstrating adaptability to different material hardness levels

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables efficient and reliable manufacturing of metal shells with easily readable identification and prevents damage to functional components, ensuring accurate assembly and enhanced manufacturing processes without occupying space within the hearing device.

Implementation Method 1

A metal shell for the hearing device is produced from metal powder using the SLS process

Methodology Applied
Scientific EffectSelective Laser Sintering: Selective Laser Sintering

Implementation Method 2

forming the preform by a 3D printing process, which is a Selective Laser Sintering (SLS) process

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 3

The surface of the preform is then smoothened by vibratory grinding

Methodology Applied
Scientific EffectVibratory grinding: Vibration

Implementation Method 4

The surface of the preform is then smoothened by vibratory grinding

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3588978B1Method for manufacturing a metal shell for a hearing device
Publication Date: 2024.08.07 SONOVA AG
  • EP3588978B1 patent drawingFigure 1~2
  • EP3588978B1 patent drawingFigure 3~4B

AI summary

The present invention provides a method for manufacturing a metal shell for a hearing device, the metal shell comprising a first opening and a second opening, wherein the second opening is smaller than the first opening, the method comprising: fabricating a preform of the metal shell, the preform comprising a main body defining an internal cavity and at least one sacrificial element formed on the main body, the main body having a first position where the first opening is located and a second position where the second opening is located; smoothening a surface of the preform; and finishing the preform to obtain the metal shell, characterized in that finishing the preform comprises removing the at least one sacrificial element. According to the present invention, it is possible to manufacture simply, efficiently and reliably the metal shell for the hearing device.