Thermoplastic Bicycle Frame Fusion via Compression Molding

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Solution Overview

Problem

Conventional methods for forming bicycle frame components from carbon reinforced composites are time-consuming, provide insufficient support leading to uneven surfaces and unstable structural rigidity, and are not suitable for mass production due to the use of thermosetting materials that are irreversible and difficult to repair or recycle.

Innovation Solution

A method involving the use of thermoplastic composite laminates formed into multiple shells that are heated and compressed to fuse together without additional adhesives, allowing for rapid connection and forming of bicycle frame components through compression molding, which can be repaired and recycled.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If thermosetting composite laminates are used with foam core and bladder, then the bicycle frame component can be formed, but the production time is long (50-60 minutes) and not suitable for mass production

Engineering Contradiction:
Improveproduction speedVSAvoidforming time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent changes the material parameter from thermosetting composite to thermoplastic composite, which allows the material to be melted and reformed. This parameter change enables faster production cycles since thermoplastic materials can be quickly reheated and remolded without the long curing times required for thermosetting materials, directly addressing the productivity and time loss issues

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the phase transition property of thermoplastic composite laminates, which can transition from solid to molten state and back. During molding, the thermoplastic material is heated to melt and then cooled to solidify, enabling rapid formation and demolding. This phase transition capability allows for much faster production cycles compared to thermosetting materials that require lengthy hardening processes

Inventive Principle:
Principle #36Phase transitions

2Manufacturing precision

If conventional cores are used, then the pre-structure can be formed, but the support is insufficient leading to uneven surfaces and unstable structural rigidity

Engineering Contradiction:
Improvesurface uniformityVSAvoidstructural rigidity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent employs a composite core structure combining foam material with a rigid frame. The foam provides bulk support while the rigid frame ensures structural stability and surface uniformity. This composite approach leverages the advantages of both materials: foam for volume and rigid frame for structural integrity, solving the insufficiency of conventional single-material cores

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The core is divided into two functional segments: an inner foam core for volume support and an outer rigid frame for structural stability. This segmentation allows each part to perform its specialized function - the foam maintains overall shape while the rigid frame ensures surface uniformity and structural rigidity, overcoming the limitations of using a single core type

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If thermosetting composite laminates are used, then the component can be formed, but the material cannot be repaired or recycled due to irreversible hardening

Engineering Contradiction:
ImproverepairabilityVSAvoidirreversible hardening
Core Design Contradiction:
Ease of repairVSStability of the object's composition

Solution Approach 1:

The patent changes the material composition from thermosetting to thermoplastic composite laminates. This parameter change is crucial because thermoplastic materials can be repeatedly heated to melt and cooled to solidify, enabling repair and recycling. The material's ability to undergo reversible phase changes allows for multiple processing cycles, unlike thermosetting materials that permanently harden

Inventive Principle:
Principle #35Parameter changes

4Strength

If additional adhesive or welding strips are used to connect shells, then the connection can be strengthened, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improveconnection strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the connection function into the molding process itself. Multiple thermoplastic composite laminates are molded simultaneously with overlapping sections that fuse together during the heating and pressing stage. This merging eliminates the need for separate adhesive application or welding steps, reducing process complexity while maintaining connection strength through the inherent bonding of thermoplastic materials

Inventive Principle:
Principle #5Merging (Combining)

5Strength

If additional adhesive or welding strips are used to connect shells, then the connection can be strengthened, but the production time increases

Engineering Contradiction:
Improveconnection strengthVSAvoidconnection time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent combines the shell formation and connection operations into a single molding process. Multiple laminates are positioned with overlapping sections and molded simultaneously, allowing the thermoplastic materials to fuse together during the heating and pressing cycle. This merging of operations eliminates sequential adhesive application or welding steps, significantly reducing production time while ensuring strong connections through thermal bonding

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces production time, enhances structural rigidity, and makes the process suitable for mass production while enabling the bicycle frame components to be lightweight, eco-friendly, and recyclable.

Implementation Method 1

The molecules of the polymers of the multiple shells are diffused for connection of the multiple shells

Methodology Applied
Scientific EffectMolecular diffusion: Diffusion

Implementation Method 2

the multiple shells are enclosed in molds for being heated and compressed

Methodology Applied
Scientific EffectThermal melting: Melting

Implementation Method 3

the multiple shells are enclosed in molds for being heated and compressed

Methodology Applied
Scientific EffectCompression molding: Compression

Data Source

PatentEP3670158B1Method for forming a bicycle frame component made of thermoplastic composite laminates and the bicycle frame for the same
Publication Date: 2022.12.28 ASTRO ENG
  • EP3670158B1 patent drawingFigure 1
  • EP3670158B1 patent drawingFigure 2
  • EP3670158B1 patent drawingFigure 3

AI summary

A method for forming a bicycle frame component (20) made of thermoplastic composite laminates has: a shell forming step: manufacturing multiple shells (20A) by compression molding; an overlapping step: overlapping two corresponding connecting margins (23) of each two of the multiple shells (20A) to form an overlapping section of the two of the multiple shells (20A) and deploying a supporting unit (30) within the multiple shells (20A) for supporting; a hot compressing connection step: heating and compressing the multiple shells (20A) to diffuse polymers of the multiple shells (20A) and to turn the multiple overlapping sections into multiple fusion areas for connection; a supporting unit removal step: removing the supporting unit (30) disposed within the bicycle frame component (20).