Inkjet Surface Texture Application for Aerodynamic Drag Reduction

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Solution Overview

Problem

Existing surface modification techniques, such as appliqué, struggle to align and apply textured layers on curved surfaces like aircraft wings or fuselages, leading to inefficiencies and reduced aerodynamic or hydrodynamic performance due to wrinkles, misalignments, and sizing issues.

Innovation Solution

A method using inkjet printers to directly apply surface textures, such as riblets, by defining the geometry of the texture, generating paths for the inkjet printers, determining firing schedules, and depositing fluid droplets to create the desired texture pattern on curved surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If appliqué technique is used to apply textured layers on curved surfaces, then surface texture can be applied, but alignment precision deteriorates due to wrinkles and misalignments

Engineering Contradiction:
Improvealignment precisionVSAvoidapplication complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical appliqué system (which involves physically attaching pre-formed textured layers) with a direct deposition system that applies texture material layer-by-layer using controlled dispensing or printing mechanisms. This substitution eliminates the alignment issues inherent in mechanical appliqué while maintaining the ability to create complex textures on curved surfaces.

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

Solution Approach 2:

The system performs preliminary scanning and mapping of the curved surface geometry before texture application. This pre-characterization of the surface allows the deposition system to pre-calculate deposition paths, angles, and material volumes, ensuring precise alignment and eliminating wrinkles before the actual texture application begins.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If textured layers are applied on curved surfaces, then aerodynamic performance can be improved, but alignment precision deteriorates leading to reduced performance

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system employs dynamic adjustment mechanisms that allow the deposition head to adapt its position, angle, and deposition rate in real-time as it moves across the curved surface. This dynamic capability ensures that each layer of texture material is deposited with precise alignment regardless of the local surface curvature, maintaining aerodynamic performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms including sensors that monitor the deposited texture layer alignment and surface geometry in real-time. This feedback allows for continuous correction of deposition parameters, ensuring that alignment precision is maintained throughout the application process and that the final texture pattern achieves the desired aerodynamic performance.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If direct texture application is used, then alignment precision is improved, but device complexity increases due to inkjet printer requirements

Engineering Contradiction:
Improvealignment precisionVSAvoidprinter system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The inkjet printer system is designed to perform multiple functions: it not only deposits texture material with high precision but also integrates scanning, surface mapping, and real-time parameter adjustment capabilities. This multi-functionality reduces the need for separate dedicated devices for each function, thereby managing overall system complexity while maintaining high alignment precision.

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

4Reliability

If textured layers are applied on curved surfaces, then drag reduction can be achieved, but sizing accuracy deteriorates resulting in overlaps and gaps

Engineering Contradiction:
Improvedrag reductionVSAvoidsizing accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary scanning and mapping of the curved surface geometry before texture application. This pre-characterization of the surface allows the deposition system to pre-calculate deposition paths, angles, and material volumes, ensuring precise alignment and eliminating wrinkles before the actual texture application begins.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms including sensors that monitor the deposited texture layer alignment and surface geometry in real-time. This feedback allows for continuous correction of deposition parameters, ensuring that alignment precision is maintained throughout the application process and that the final texture pattern achieves the desired aerodynamic performance.

Inventive Principle:
Principle #23Feedback

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 allows for precise and controlled application of surface textures on complex, curved surfaces, enhancing aerodynamic or hydrodynamic performance by reducing drag through optimized texture patterns and alignment.

Implementation Method 1

The inkjet printer comprises a piezoelectric actuator in contact with fluid. The piezoelectric actuator is configured to change shape in response to an electrical pulse applied to the piezoelectric actuator, thereby generating a pressure wave in the fluid, and forcing a controlled amount of fluid out of the inkjet printer as the fluid droplets.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

depositing fluid droplets by the inkjet printers onto the surface to create the surface texture

Methodology Applied
Scientific EffectInkjet printing deposition: Deposition (physical)

Implementation Method 3

curing the fluid droplets, thereby causing materials in the fluid droplets to polymerize and bond with the surface

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP4556246A1Method for directly applying surface texture for improved aerodynamics using inkjet printers
Publication Date: 2025.05.21 THE BOEING CO
  • EP4556246A1 patent drawingFigure 1
  • EP4556246A1 patent drawingFigure 2A~2B
  • EP4556246A1 patent drawingFigure 3

AI summary

A method for directly applying surface texture on the surface of a part to reduce drag is provided. The method comprises defining a geometry of the surface texture on the surface of the part and generating paths for inkjet printers to move over the surface of the part. The method comprises determining the number of passes and firing schedules for the inkjet printers to create the surface texture. The method comprises locating and aligning the part in a work cell. The method comprises depositing fluid droplets by the inkjet printers onto the surface to create the surface texture.