Watch Strap Co-Extrusion Embedding Decorations

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Solution Overview

Problem

Current manufacturing processes for complex patterned bracelets are unsuitable for high-volume production due to multi-step batch processes, surface printing limitations, adhesion issues, and sensitivity to mechanical and chemical wear, which lead to aesthetic degradation over time.

Innovation Solution

A co-extrusion coating process that integrates printing or engraving of decorations on a substrate before coating with synthetic materials, allowing for complex patterns to be embedded within the bracelet, ensuring stability and adhesion, and using transparent or translucent outer layers to reveal the design while protecting it from external damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If digital printing is used on the surface of molded substrates, then design variety is improved, but mechanical wear resistance deteriorates and adhesion to low surface energy materials is poor

Engineering Contradiction:
Improvedesign varietyVSAvoidmechanical wear resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent embeds the printed decorative film within the substrate material itself, nesting the design between two protective layers of the substrate. This integration protects the design from mechanical wear while maintaining design variety through the printing process.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The printing process is performed on the substrate surface before the final molding process completes. This preliminary action allows the design to be embedded within the material structure, ensuring it is protected from wear from the outset rather than applied as a surface coating.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If injection molding process is used with printed film, then design integration is improved, but manufacturing complexity and production time increase

Engineering Contradiction:
Improvedesign integrationVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the printing process with the extrusion molding process by printing directly on the substrate as it is being formed, and then completing the molding in the same continuous operation. This merging eliminates separate steps for film application, positioning, and protective layer formation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substrate material serves multiple functions: it provides the structural base, the printing surface, and the protective encapsulation layer. This multi-functionality eliminates the need for separate protective films and simplifies the overall manufacturing process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If surface printing is used on silicone-type bracelets, then design application is simplified, but ink adhesion deteriorates due to low surface energy

Engineering Contradiction:
Improvedesign applicationVSAvoidink adhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The printing is performed on the substrate surface before the final molding encapsulates it. This preliminary printing on the raw substrate surface, before any protective coatings are applied, ensures better ink penetration and adhesion to the base material.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The printed design is embedded within the substrate structure, nested between layers of the molded material. This integration protects the ink from surface wear and chemical damage while maintaining adhesion to the substrate.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Adaptability or versatility

If multi-step batch manufacturing processes are used, then design complexity is improved, but production rate deteriorates

Engineering Contradiction:
Improvedesign complexityVSAvoidproduction rate
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements a continuous extrusion process where the substrate is formed and printed upon in a single continuous operation, rather than through discrete batch steps. This continuity maintains design complexity while dramatically increasing production rate by eliminating idle time between steps.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent merges the substrate formation and decorative printing steps into a single integrated process. By combining these operations that were previously separate batch steps, the process achieves both complex designs and high production rates.

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

Enables cost-effective, high-rate production of personalized bracelets with intricate designs that are durable and resistant to wear, maintaining aesthetic appeal over time by embedding patterns within the material and using compatible ink adhesion techniques.

Implementation Method 1

coating by co-extrusion of the first and second faces of the substrate

Methodology Applied
Scientific EffectCo-extrusion: Extrusion

Data Source

PatentEP3554305B1Method for manufacturing a trim panel with decoration for watch or jewel
Publication Date: 2024.09.25 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3554305B1 patent drawingFigure 1~2
  • EP3554305B1 patent drawingFigure 3
  • EP3554305B1 patent drawingFigure 4

AI summary

The present invention relates to a production method for a trim part for a watch or jewellery piece, in particular a bracelet or watch strap (5), comprising the steps of: - providing a substrate (1) comprising a first face opposite a second face, - coating by co-extrusion on the first face and on the second face of said substrate (1) with, respectively, a first and a second strip (2) of synthetic material; the first strip (2) forming on the first face a transparent or translucent layer allowing the substrate (1) to be held entirely or partially visible.