Fastener Stringer Plating Uniformity via Insulating Tape

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Solution Overview

Problem

Existing metal fastener electroplating methods, such as barrel plating and feeding drum methods, face challenges in achieving uniform plating film thickness and deposition properties, leading to variations in corrosion resistance, abrasion resistance, and sliding resistance, and result in waste of plating solution and potential deformation of elements.

Innovation Solution

A method where metal elements in a fastener chain are brought into contact with a plurality of conductive media flowably accommodated in insulating containers, allowing current to be applied via the conductive media while traveling in a plating solution, ensuring uniform plating on one main surface side without conductive media on the other side, enhancing plating film uniformity and deposition properties at engaged portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conductive yarns are knitted into element attachment portions to electrically connect elements for continuous electroplating, then uniform plating can be achieved, but the conductive yarn is expensive and easily cut during knitting, resulting in poor productivity

Engineering Contradiction:
Improveplating uniformityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention extracts and removes the conductive yarn component from the element attachment portions, replacing it with insulating tape. This eliminates the problems of expensive materials, easy cutting, and poor productivity while maintaining the electrical connection function through an alternative method using the fastener chain structure itself

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces insulating tape as an intermediary material that replaces conductive yarn. The insulating tape serves as a mediator to protect the metal elements during electroplating while allowing electrical connection through the fastener chain structure, resolving the contradiction between plating uniformity and productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If feeding drums are used to surface-treat elements by pressing and passing through, then electroplating can be performed without conductive yarn, but non-uniform contact results in large variation in plating film thickness

Engineering Contradiction:
Improveelectroplating feasibilityVSAvoidplating film thickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention introduces insulating tape as an intermediary that ensures uniform contact between elements and the electroplating solution. The tape acts as a mediator that distributes electrical current evenly across all elements while maintaining consistent contact pressure, eliminating the non-uniform contact problem of feeding drums

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention applies insulating tape uniformly across all element attachment portions, creating homogeneous conditions for electroplating. This ensures that all elements receive identical treatment during the electroplating process, resulting in uniform plating film thickness across the entire fastener chain

Inventive Principle:
Principle #33Homogeneity

3Productivity

If elements are plated while fixed to fastener tapes, then productivity is improved, but deformation and cracks occur during caulking

Engineering Contradiction:
Improveproduction efficiencyVSAvoidelement integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The insulating tape acts as a protective intermediary between the metal elements and the fastener tape during the caulking process. This intermediary layer prevents direct contact that would cause deformation and cracks, while still allowing the elements to be firmly fixed to the fastener tapes for high productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating tape provides beforehand cushioning protection to the metal elements before the caulking process occurs. By placing the protective tape in advance, the elements are shielded from deformation and cracking during subsequent manufacturing steps, ensuring element integrity while maintaining productivity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Manufacturing precision

If barrel plating is used to plate the entire surface of elements, then complete coverage is achieved, but plating solution is wasted on non-visible surfaces

Engineering Contradiction:
Improveplating coverageVSAvoidplating solution waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The invention extracts and removes the unnecessary plating from non-visible surfaces by using insulating tape to block the electroplating solution from contacting the back sides of elements. This eliminates waste of plating solution on surfaces that will not be visible in the final product while maintaining complete coverage on visible surfaces

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by differentiating the plating treatment between visible and non-visible surfaces. Insulating tape is applied selectively to block plating on non-visible surfaces, while visible surfaces receive complete plating coverage. This localized approach optimizes plating solution usage while maintaining product quality

Inventive Principle:
Principle #3Local quality

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 approach results in metal fasteners with improved thickness uniformity and enhanced plating deposition properties at engaged portions, reducing waste and providing high-quality, cost-effective products with varied color tones.

Implementation Method 1

electroplating is carried out while continuously conveying the elongated product in a plating bath

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

a method where metal elements in a fastener chain are brought into contact with a plurality of conductive media flowably accommodated in insulating containers, allowing current to be applied via the conductive media

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3556909B1Fastener stringer provided with metal element row having plating film, fastener chain, and slide fastener
Publication Date: 2023.04.19 YKK CORP
  • EP3556909B1 patent drawingFigure 1
  • EP3556909B1 patent drawingFigure 2
  • EP3556909B1 patent drawingFigure 3

AI summary

Provided is a fastener stringer including a row of metal elements having a plating film formed with improved thickness uniformity without waste, even if the elements are not electrically connected to each other in advance. For each of ten adjacent metal elements 3 of the fastener stinger, 0.6 ≤ D1 / A1 ≤ 2.0 is satisfied in which A1 represents an average value of thickness of the plating film for the ten metal elements 3 at element center on either one main surface side of the fastener tape 1, and D1 represents thickness of the plating film for each of the metal elements 3 at the element center on the one main surface side of the fastener tape 1.