Additive Manufacturing Conformal Heating Circuit Assembly

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Solution Overview

Problem

Existing heating circuit manufacturing methods in the automotive and aviation industries face issues such as insufficient repeatability, photoresist alignment problems, delamination, poor adhesion, and chemical waste, with limited applicability to three-dimensional components and weight restrictions.

Innovation Solution

The method involves additive manufacturing of a thermoplastic, non-planar substrate with a conforming topology and printing an electrically conductive element, followed by the addition of a thermally conductive layer, using techniques like fused deposition modeling, to create a heating circuit assembly that aligns with the component's shape and enhances structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photochemical etching is used to manufacture heating circuits, then heating circuits can be produced on substrate, but repeatability is insufficient due to over or under-etching and alignment issues

Engineering Contradiction:
Improveetching precisionVSAvoidrepeatability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the photochemical etching process with a direct additive manufacturing process where conductive material is deposited layer-by-layer to form heating circuit traces. This eliminates photoresist alignment issues, over/under-etching problems, and chemical waste generation while achieving precise trace geometry through controlled material deposition.

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

Solution Approach 2:

The invention changes the manufacturing approach from subtractive (etching away material) to additive (building up conductive material). The conductive material is deposited in a controlled manner with precise control over trace width, height, and pattern, achieving consistent repeatability without the alignment and etching control issues of photochemical methods.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If photochemical etching method is used, then heating circuits can be manufactured, but the process is time and labor intensive with significant chemical waste

Engineering Contradiction:
Improvemanufacturing capabilityVSAvoidchemical waste
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent replaces the multi-step photochemical process (photoresist application, exposure, development, etching, rinsing) with a single additive manufacturing process that directly deposits conductive material. This eliminates all chemical waste associated with photoresists and etchants while reducing manufacturing time and labor requirements.

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

Solution Approach 2:

The invention extracts and eliminates the harmful chemical components (photoresists, etchants, rinsing solutions) from the manufacturing process. The additive manufacturing approach uses only the necessary conductive material, significantly reducing substance loss and chemical waste while maintaining manufacturing capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If traditional heating circuit assembly is used, then heating function is provided, but application to three-dimensional component is limited

Engineering Contradiction:
Improveapplication flexibilityVSAvoidcomponent geometry compatibility
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The patent transitions from planar heating circuit traces to three-dimensional conformal structures. The additive manufacturing process builds up conductive material in multiple layers that can conform to complex 3D surfaces, enabling application to curved, irregular, and three-dimensional components while maintaining heating functionality.

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

Solution Approach 2:

The invention enables heating circuits to conform to curved and irregular surfaces by depositing material in layers that follow the underlying 3D geometry. This allows adaptation to spherical, cylindrical, or any complex curved surfaces, greatly expanding application versatility beyond flat planar substrates.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Strength

If conventional manufacturing methods are used, then heating circuits can be produced, but structural integrity and weight restrictions present challenges

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent uses composite structures where a substrate (potentially lightweight material) is combined with precisely deposited conductive heating elements. The additive manufacturing process allows optimization of material distribution, placing conductive material only where needed for heating function, reducing overall weight while maintaining structural integrity through the layered construction approach.

Inventive Principle:
Principle #40Composite materials

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 improves the repeatability and structural integrity of heating circuits, allows for complex three-dimensional designs, reduces material consumption, and minimizes weight while providing effective thermal conductivity and adhesion, suitable for de-icing and comfort applications.

Implementation Method 1

the substrate is formed through a fused deposition modeling technique

Methodology Applied
Scientific EffectFused deposition modeling:

Implementation Method 2

the method includes the step of curing the printed element before additive manufacturing the layer

Methodology Applied
Scientific EffectCuring:

Implementation Method 3

the layer includes at least one of boron nitride, aluminum oxide, aluminum nitride, silicon carbide, and diamond particles to control thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3328158B1Heating circuit assembly and method of manufacture
Publication Date: 2022.08.31 RTX CORP
  • EP3328158B1 patent drawingFigure 1~2
  • EP3328158B1 patent drawingFigure 3~4
  • EP3328158B1 patent drawingFigure 5

AI summary

A heating circuit assembly (20) and method of manufacture includes an electrically conductive heating element (26) having a pattern (30). An electrically non-conductive substrate (22) is additive manufactured and secured to the element (26) for structural support. The substrate (22) has a topology (37) that generally aligns with the pattern (30) of the element (26) thereby reducing the assembly weight and minimizing substrate (22) material waste.