Z-axis Printhead Position Control via Test Pattern Dispersion
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Solution Overview
Problem
Current three-dimensional printing systems face challenges in accurately identifying and controlling the relative position of printheads with respect to a substrate along the z-axis, which affects the precision and reliability of the printing process, leading to potential clogging and misfiring of jets.
Innovation Solution
A method and system that utilize a controller and image sensor to form test patterns on a substrate, measure the dispersion of marks, and adjust the z-axis distance between printheads and the substrate using actuators to maintain precise positioning, generating a profile for future printing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the printhead is positioned close to the substrate for precise drop placement, then manufacturing precision is improved, but the risk of clogging and misfiring increases
Solution Approach 1:
The system uses an image sensor to capture images of test patterns printed on the substrate, measures the actual drop placement positions, and feeds back this information to the controller. The controller then adjusts the printhead position or ejection parameters to optimize both precision and reliability, preventing clogging and misfiring through continuous monitoring and adjustment.
2Device complexity
If the z-axis distance is not accurately controlled, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The system replaces complex mechanical positioning systems with an optical measurement system. An image sensor captures images of test patterns, and software algorithms calculate the actual z-axis distance based on drop placement dispersion, eliminating the need for complex mechanical encoders and position sensors while maintaining high precision.
3Measurement precision
If test patterns are printed and measured to identify z-axis distance, then measurement precision is improved, but productivity is reduced
Solution Approach 1:
The system performs z-axis distance measurement and optimization only when necessary, such as during initial setup, after maintenance events, or when quality deviations are detected. During normal production, the optimized parameters are used without repeated measurement cycles, balancing measurement precision needs with productivity requirements.
Data Source
AI summary
A method of operating a three-dimensional object printer includes generation of a printed predetermined test pattern on a substrate in the printer with a plurality of ejectors in a printhead. An image sensor generates image data of the printed test pattern and a controller identifies a z-axis distance between the printhead and the substrate that receives the test pattern with reference to an identified dispersion between cross-process direction distances separating printed marks in the test pattern.