Energy Dissipative Nozzles for Drop-on-Demand Printing
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Solution Overview
Problem
Drop-on-demand printing systems, such as ink-jet or liquid metal-jet, face challenges in printing speed and accuracy due to unpredictable droplet speed, shape, and volume, which are influenced by the dynamics of the liquid in the tank and the time it takes for the meniscus to settle, leading to irregularities and deviations from designed geometries.
Innovation Solution
A nozzle design with a constricted dissipative section and a shaping tip, where the dissipative section obstructs fluid flow and includes multiple internal channels or porous media to control the relaxation time and droplet characteristics, allowing for consistent droplet ejection by decoupling the control of relaxation time from droplet shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nozzle ejects droplets at high frequency to improve printing speed, then productivity increases, but droplet consistency deteriorates due to meniscus instability
Solution Approach 1:
The nozzle is divided into functionally independent sections: a dissipative section for energy dissipation and meniscus stabilization, and a shaping section for droplet formation. This segmentation allows each section to optimize its specific function without interfering with the other, enabling high-frequency operation while maintaining droplet consistency.
Solution Approach 2:
The dissipative section acts as an intermediary element between the fluid supply and the droplet formation zone. It absorbs kinetic energy and dampens meniscus oscillations, creating stable initial conditions for subsequent droplet ejection at high frequencies.
2Manufacturing precision
If the nozzle design focuses on droplet shaping to improve manufacturing precision, then droplet characteristics improve, but relaxation time increases reducing productivity
Solution Approach 1:
The nozzle is divided into functionally independent parts: a dissipative section for energy dissipation and meniscus stabilization, and a shaping section for droplet formation. This segmentation allows each section to optimize its specific function without interfering with the other, enabling high-frequency operation while maintaining droplet consistency.
Solution Approach 2:
The dissipative function is extracted from the droplet formation process and placed in a separate upstream section. This removes the conflict between energy dissipation time and droplet shaping time, allowing the shaping section to focus solely on precision while the dissipative section handles relaxation independently.
3Ease of manufacture
If the nozzle uses a simple geometry to reduce device complexity, then ease of manufacture improves, but droplet characteristics become unpredictable
Solution Approach 1:
Different sections of the nozzle have different geometric qualities optimized for their specific functions. The dissipative section has a constricted geometry with specific length-to-diameter ratios for energy dissipation, while the shaping section has geometry optimized for droplet formation. This local optimization achieves precise droplet control without requiring complex overall design.
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 nozzle design achieves stable drop-to-drop behavior with consistent droplet characteristics, reducing drop-to-drop variation and enabling faster firing frequencies while maintaining droplet uniformity and accuracy, thus improving printing quality and efficiency.
Implementation Method 1
a constricted dissipative section in communication with the tank and configured to obstruct fluid flow... The constricted dissipative section may further include at least three internal channels not in communication with one another
Data Source
AI summary
A nozzle for a printing system is disclosed. The nozzle includes a tank in communication with a source of printing material. The nozzle also includes a constricted dissipative section in communication with the tank, which may include an elongated internal channel. The nozzle may also include a shaping tip in communication with the constricted dissipative section may include an exit orifice. The constricted dissipative section may be axisymmetric and may include at least three internal channels not in communication with one another. Also disclosed is an array of nozzles for a printing system including a plurality of nozzles, with each nozzle including a tank in communication with a source of printing material, a constricted dissipative section in communication with the tank and configured to obstruct fluid flow and having an elongated internal channel, and a shaping tip in communication with the constricted dissipative section may include an exit orifice.