Radially Flared Metal Member Assembly in Brittle Silicon Parts

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Solution Overview

Problem

Current assembly methods for silicon-based parts with metal components are prone to breakage due to axial stresses and inadequate bonding, leading to costly and inefficient operations.

Innovation Solution

A method involving an adhesive-free assembly where a radially flared metal member is elastically and plastically deformed within a silicon-based part's aperture, applying uniform radial stress to secure the assembly without axial stress, using tools to deform the flared portion and create micro-grooves for securement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bonding is used to secure silicon-based parts to metal components, then the assembly is secured, but the operation becomes extremely delicate and expensive

Engineering Contradiction:

Improveassembly securityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the chemical bonding system with a mechanical deformation system. A metal member with a flared portion is inserted into the silicon part, and the flared portion is radially deformed to create friction-based mechanical interlocking. This substitution eliminates the need for delicate bonding operations while maintaining secure assembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If axial stress is applied to assemble the intermediate part folded over the silicon part, then the parts are bound, but the silicon part breaks due to purely axial stresses

Engineering Contradiction:

Improveassembly bindingVSAvoidsilicon part integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent transitions from uniaxial (axial) stress application to multiaxial stress by introducing radial deformation. The flared portion of the metal member is deformed radially outward against the inner wall of the silicon part, creating friction-based binding without axial compressive loads on the silicon. This dimensional change in stress application prevents silicon breakage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If faceting is used to bind the parts, then the parts are secured, but the stress distribution becomes non-uniform and the silicon part breaks

Engineering Contradiction:

Improveparts bindingVSAvoidstress distribution uniformity

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies local quality by creating a circumferential friction interface through radial deformation of the flared portion. Instead of localized faceting contacts, the entire circumferential surface of the flared portion contacts the silicon part wall, distributing stress uniformly around the circumference. This local friction-based contact prevents stress concentration and silicon breakage.

Inventive Principle:

Principle #3Local quality

4Reliability

If the member is rigidly fixed in the aperture, then the assembly is secure, but the part cannot adapt to manufacturing dispersions

Engineering Contradiction:

Improveassembly securityVSAvoidmanufacturing dispersion tolerance

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamics by using elastic deformation of the flared portion during assembly. The flared portion is radially deformed elastically to expand against the silicon part wall, creating friction-based holding. This elastic compliance allows the assembly to adapt to manufacturing tolerances and dispersions while maintaining secure connection, unlike rigid fixed designs.

Inventive Principle:

Principle #15Dynamics

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 securely assembles silicon-based parts with metal components without breakage, allowing for higher stress tolerance beyond previous limits, up to 1.5-2 GPa, and adapts to manufacturing dispersions, ensuring non-destructive assembly and precision without bonding.

Implementation Method 1

elastically and plastically deforming the flared portion of said member in the aperture by moving two tools towards each other axially

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

elastically and plastically deforming the flared portion of said member in the aperture

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

exert a radial stress against the wall of the part surrounding the aperture

Methodology Applied

Scientific EffectRadial stress: Stress Relaxation

Data Source

PatentUS8707536B2Assembly of a part that has no plastic domain

Publication Date: 2014.04.29 NIVAROX FAR SA

AI summary

A method of assembling a member made of a first material in a part made of a second material having no plastic domain, includes forming the part with an aperture, inserting a radially flared portion of the member into the aperture, without any stress, and elastically and plastically deforming the flared portion of the member in the aperture by moving two tools towards each other axially, respectively on the top and bottom parts of the flared portion, so as to exert a radial stress against the wall of the part surrounding the aperture, causing the elastic deformation of the part, to secure the assembly in a manner that is not destructive for said part. The member can be a timepiece.