Robotic Inkjet Printhead Alignment for Aircraft Livery Printing

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Solution Overview

Problem

The painting of aircraft is a time-consuming and complex process due to the unique geometry and large surface area, requiring precise application of multi-colored images with complex geometric shapes, which conventional methods struggle to achieve efficiently and effectively.

Innovation Solution

An automated image forming system using a robotic mechanism with an inkjet printhead and high-bandwidth actuators, capable of printing image slices with overlapping image gradient bands and reference lines to ensure precise alignment and uniformity, allowing for the application of complex and multi-colored images in a single pass on large-scale surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional painting methods are used, then the painting process can be performed with simple equipment, but the production time is excessive and manufacturing precision is insufficient

Engineering Contradiction:
Improvepainting speedVSAvoidpainting system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces conventional spray painting equipment with a robotic inkjet printing system. The robotic mechanism precisely positions an inkjet printhead to deposit paint droplets directly onto aircraft surfaces, eliminating the need for complex masking and manual spraying operations. This substitution of mechanical spray systems with automated inkjet deposition technology achieves faster painting speed and better precision while managing system complexity through automation.

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

Solution Approach 2:

The patent changes the fundamental parameters of the painting process by using digital control to precisely manage droplet deposition. The system controls droplet size, spacing, and placement with high precision through digital signaling to the inkjet printhead. This parameter control enables complex geometric shapes and color combinations to be applied efficiently without requiring multiple manual masking steps, thereby increasing productivity while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple masking and painting steps are performed for each color, then manufacturing precision can be maintained, but the production time increases significantly

Engineering Contradiction:
Improveimage alignment precisionVSAvoidpainting cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent segments the painting process into digital image data that can be processed and applied in a single pass. Instead of treating each color as a separate requiring masking step, the system divides the final image into controllable droplet patterns that are deposited sequentially by the inkjet printhead. This segmentation of the image into digital coordinates allows all colors and geometric shapes to be applied in one continuous operation, dramatically reducing cycle time while maintaining precision through digital control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple painting operations into a single integrated robotic printing process. The inkjet printhead combines the functions of multiple spray guns that would otherwise require separate masking and painting steps for different colors. By merging these operations into one automated process with continuous droplet deposition, the system achieves both high precision image alignment and reduced production time, eliminating the need for repeated masking and demasking cycles.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If paint is applied with high control for coating thickness, then performance requirements are met, but the complexity of the painting process increases

Engineering Contradiction:
Improvecoating thickness controlVSAvoidpaint application control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical spray control systems with a more manageable inkjet droplet deposition system. The robotic inkjet printhead inherently provides precise control over coating thickness through digital control of droplet size, volume, and placement frequency. This substitution simplifies the control mechanism compared to traditional spray systems that require complex airflow, pressure, and nozzle positioning control to achieve the same level of thickness precision.

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

Solution Approach 2:

The inkjet printhead system provides self-regulating control over coating thickness through its digital deposition mechanism. The system automatically adjusts droplet parameters based on programmed instructions, eliminating the need for complex external control systems. The robotic mechanism precisely positions the printhead and the inkjet technology inherently controls droplet placement, creating a self-service system that maintains consistent coating thickness without requiring elaborate control hardware or manual intervention.

Inventive Principle:
Principle #25Self-service

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

The system enables precise, cost-effective, and timely application of aircraft liveries by preventing gaps between image slices, ensuring high-quality, uniform images on complex aircraft surfaces, reducing production time and costs.

Implementation Method 1

a printhead having a plurality of nozzles for ejecting droplets of ink or paint

Methodology Applied
Scientific EffectInkjet ejection: Jet

Data Source

PatentEP3628501B1Method for printing an image on a surface
Publication Date: 2021.08.04 THE BOEING CO
  • EP3628501B1 patent drawingFigure 1
  • EP3628501B1 patent drawingFigure 2
  • EP3628501B1 patent drawingFigure 3

AI summary

A method for printing an image (400) on a surface (102), comprising: printing, using a printhead (300) mounted to an arm (210) of a robot (202), a new image slice (406) on the surface (102) while moving the printhead (300) over the surface (102) along a rastering path (350); printing a reference line (322) on the surface (102) when printing the new image slice (406); sensing, using a reference line sensor (326), the reference line (322) of an existing image slice (408) while printing the new image slice (406); and adjusting the lateral position of the new image slice (406) based on a sensed position of the reference line (322) in a manner aligning a side edge (416) of the new image slice (406) with the side edge (416) of the existing image slice (408).