Inkjet Printing Encoder Pattern Alignment
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Solution Overview
Problem
Current inkjet printing technologies face challenges in achieving high positional accuracy on large-scale, complex surfaces such as aircraft fuselages, requiring improvements in robotic precision and handling of curved geometries to produce seamless graphic images without distortion.
Innovation Solution
The implementation of an encoded pattern system where a dedicated print head deposits both the graphic swathe and an encoder pattern simultaneously, allowing the control circuit to precisely align subsequent swathes based on the encoder pattern, thereby achieving high accuracy without relying on the absolute accuracy of the robotic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current inkjet printing technology is used on flat surfaces, then printing accuracy is maintained, but the system cannot handle complex curved surfaces
Solution Approach 1:
The system performs preliminary actions by projecting a laser line onto the surface and capturing it with a camera to map the surface geometry before printing. This pre-mapping allows the system to compensate for surface curvature and maintain printing accuracy on complex geometries.
Solution Approach 2:
The patent replaces reliance on mechanically precise robotic positioning with an optical measurement and compensation system. Instead of depending on the robotic arm's absolute positioning accuracy, the system uses laser line projection and camera capture to determine actual surface geometry and adjusts printing accordingly.
2Manufacturing precision
If robotic positioning accuracy is improved to achieve high precision printing, then printing accuracy increases, but system complexity and cost increase
Solution Approach 1:
The system substitutes complex mechanical precision requirements with an optical measurement and software compensation approach. The laser line projector and camera system replaces the need for high-precision mechanical positioning, allowing standard robotic arms to achieve high printing accuracy through software-based geometric compensation.
Solution Approach 2:
The patent introduces an intermediary measurement system consisting of the laser line projector and camera that acts as a mediator between the robotic arm and the surface. This intermediary captures surface geometry information and enables the control system to compensate for positioning variations without requiring the robotic arm itself to be highly precise.
3Manufacturing precision
If multiple paint coats are applied to achieve complete coverage on complex surfaces, then coverage quality improves, but processing time increases
Solution Approach 1:
The system performs preliminary mapping of the surface geometry using laser line projection and camera capture before the actual printing process. This pre-characterization of the surface allows the system to plan and execute single-pass or reduced-pass printing with accurate droplet placement, eliminating the need for multiple coats while maintaining complete coverage quality.
Data Source
AI summary
Large area inkjet printing includes the precise deposition of a number of graphic swathes on complex surface to form a continuous graphic image. Each of the graphic swathes should be aligned such that no spaces, gaps, or discontinuities exist within the final graphic image. A large area inkjet printing system provides the requisite accuracy for each graphic swathe forming the final graphic image through the use of an encoder pattern. An encoder pattern is deposited on the surface in a known location with respect to the most recently deposited graphic swathe. The high-accuracy inkjet printing system locates the print head with respect to the encoder pattern thereby permitting the precise positioning of the current graphic swathe.