Segmented Conductive Element for Wide Induction Welding

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Solution Overview

Problem

Existing induction welding technologies fail to produce a wide, robust weld seam, particularly when joining fiber-reinforced thermoplastic materials, which limits the strength and reliability of the bond.

Innovation Solution

The method involves arranging conductive elements with specific configurations, such as parallel, angularly offset, or concentric loop geometries next to the surfaces of thermoplastic bodies, to generate eddy currents that excite fibers and produce a wider weld seam during induction welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional single-segment conductive element is used for induction welding, then the welding process is simple, but the weld seam is narrow and not robust

Engineering Contradiction:
Improveweld seam robustnessVSAvoidconductive element configuration
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The conductive element is divided into multiple segments (first conductive element segment, second conductive element segment, etc.) that can be independently configured. Each segment targets specific fiber orientations, allowing the weld seam to engage multiple fiber directions simultaneously, thereby producing a wider and more robust weld than a single conventional conductive element could achieve.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive elements are arranged in a three-dimensional configuration where at least one conductive element segment is positioned vertically above another segment. This vertical stacking creates multiple engagement zones with the workpiece at different heights, enabling the induction welding system to simultaneously heat fibers oriented in different directions and produce an expanded, multi-dimensional weld seam.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the conductive element is arranged to match multiple fiber orientations, then the weld seam width increases, but the alignment precision required increases

Engineering Contradiction:
Improveweld seam widthVSAvoidconductive element alignment
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

Each conductive element segment is specifically oriented to match particular fiber directions (e.g., first segment parallel to first fibers, second segment parallel to second fibers). This local optimization allows each segment to efficiently engage its target fiber orientation while the collective arrangement of multiple segments achieves broad coverage across different fiber directions, maintaining alignment precision for each individual segment while achieving overall wide seam coverage.

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 a more robust and wider weld seam, enhancing the strength and reliability of the bond between fiber-reinforced thermoplastic materials, improving the overall joining process.

Implementation Method 1

The conductive element includes a first segment and a second segment. The first segment is at least substantially parallel with the plurality of parallel first fibers. The second segment is at least substantially parallel with the plurality of parallel second fibers.

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

The first thermoplastic body is induction welded to the second thermoplastic body using the conductive element.

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

The induction welding may include exciting some of the parallel first fibers and some of the parallel second fibers with eddy currents generated by the conductive element.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4397474A1Induction welding thermoplastic bodies with multiple fiber orientations
Publication Date: 2024.07.10 ROHR INC
  • EP4397474A1 patent drawingFigure 1
  • EP4397474A1 patent drawingFigure 2
  • EP4397474A1 patent drawingFigure 3

AI summary

During a manufacturing method, a first thermoplastic body is arranged with a second thermoplastic body. The first thermoplastic body and/or the second thermoplastic body includes a plurality of fibers embedded within a thermoplastic matrix. The fibers include a plurality of parallel first fibers and a plurality of parallel second fibers that are angularly offset from the parallel first fibers. A conductive element is arranged vertically next to a surface of the first thermoplastic body. The first thermoplastic body is induction welded to the second thermoplastic body using the conductive element. The conductive element includes a first segment and a second segment. The first segment is at least substantially parallel with the plurality of parallel first fibers. The second segment is at least substantially parallel with the plurality of parallel second fibers. A first portion of the conductive element is vertically above and overlaps a second portion of the conductive element.