Composite Part Fastening Using Vibration-Cured Resin Bonding

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Solution Overview

Problem

Conventional methods for fastening objects, particularly in industries using lightweight materials like fiber composites, face challenges such as limited mechanical strength, precision issues in positioning, and slow curing times of adhesives, which hinder efficient industrial production.

Innovation Solution

A method utilizing mechanical vibration to distribute and cure resin between objects, allowing for a strong adhesive bond without weakening the materials and enabling rapid curing, even on complex surfaces with structures like undercuts, thereby overcoming the limitations of traditional fastening techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional riveting techniques are used to fasten objects to fiber composite materials, then mechanical connection is achieved, but the small ductility of fiber composite materials limits the effectiveness and requires pre-drilling which compromises positioning precision

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidpositioning precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical riveting system with an adhesive bonding system. Instead of using rigid mechanical connectors that require pre-drilled holes, the invention uses adhesive material that can be applied directly to the surface, eliminating the need for pre-drilling and preserving positioning precision while achieving strong mechanical connection through chemical bonding.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the bonding mechanism from mechanical (rigid connection through holes) to chemical (adhesive bonding). This parameter change allows the adhesive to flow and conform to the surface geometry, compensating for positioning tolerances and achieving both strong connection and high positioning precision.

Inventive Principle:
Principle #35Parameter changes

2Strength

If adhesive connections are used to fasten objects, then strong bonding is achieved, but the curing time is extended which reduces production efficiency

Engineering Contradiction:
Improvebond strengthVSAvoidproduction speed
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent employs periodic ultrasonic vibration during the adhesive bonding process. The ultrasonic energy is applied in a periodic manner to accelerate the curing reaction, reducing the overall curing time from minutes to seconds while maintaining strong bond strength, thus resolving the contradiction between bond strength and production speed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses mechanical vibration (ultrasonic frequency) to accelerate the curing process of the adhesive. The vibrational energy activates the adhesive material, causing rapid cross-linking and curing without compromising the final bond strength, thereby significantly increasing production efficiency.

Inventive Principle:
Principle #18Mechanical vibration

3Loss of time

If UV curable adhesives are used to reduce curing time, then faster curing is achieved, but transparent connectors are required which limits design flexibility and UV penetration is needed which adds complexity

Engineering Contradiction:
Improvecuring timeVSAvoidtransparency and penetration requirements
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent replaces UV light-based curing with mechanical vibration-based curing. Instead of requiring transparent connectors and UV penetration, the invention uses ultrasonic mechanical vibration that can penetrate opaque materials, eliminating the transparency constraint and simplifying the design while achieving rapid curing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If adhesive bonds are used to connect objects, then mechanical strength is achieved, but the bond strength is limited by the outermost layer strength and glue line sensitivity

Engineering Contradiction:
Improvebond strengthVSAvoidbond reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent uses mechanical vibration to enhance the adhesive bonding process, creating a more reliable bond. The vibration energy promotes better adhesive flow, wetting, and penetration into the substrate, creating a more robust connection that overcomes the limitations of outermost layer strength and glue line sensitivity, thereby improving bond reliability.

Inventive Principle:
Principle #18Mechanical vibration

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 provides a strong, reliable mechanical bond that accelerates the curing process by an order of magnitude, reduces the need for precise positioning, and eliminates the requirement for pre-drilled openings, making it suitable for industrial production.

Implementation Method 1

a method of fastening a second object (2) to a first object (1), comprising the step of placing the second object (2) relative to the first object (1), with a resin material (3) between the attachment surfaces, causing mechanical vibration to act on the resin material (3)

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Implementation Method 2

resin denotes any substance that is flowable at least during one stage of the process (generally a viscous liquid) and is capable of hardening permanently by covalent bonds generated between molecules of the resin

Methodology Applied
Scientific EffectCuring: Chemical Bonding

Data Source

PatentEP3442778B1Fastening objects to each other
Publication Date: 2023.12.20 WOODWELDING AG
  • EP3442778B1 patent drawingFigure 1a~1c
  • EP3442778B1 patent drawingFigure 1d~3
  • EP3442778B1 patent drawingFigure 4~7

AI summary

Method of fastening a second object (2) to a fiber composite part (1) comprising a structure of fibers embedded in a matrix material is provided, the method comprising: - providing the fiber composite part comprising an attachment surface, with a portion of the structure of fibers being exposed at the attachment surface; - providing the second object; - placing the second object relative to the fiber composite part, with a resin (3) in a flowable state between the attachment surface and the connector; - pressing the second object and the fiber composite part against each other and causing mechanical vibration to act on the second object or the fiber composite part or both, thereby causing the resin to infiltrate the exposed structure of fibers and activating the resin to cross-link; - whereby the resin, after cross-linking, secures the second object to the fiber composite part.