Two-Stage Atomization Spray Device for Thin Film Precision
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Solution Overview
Problem
Conventional spray devices struggle to form thin films with precise thickness on uneven surfaces and spherical or cylindrical objects, achieving low coating efficiency and high film thickness variation due to large particle diameters and difficulty in adjusting small liquid amounts.
Innovation Solution
A spray device with a slender needle and adjustable nozzle system that uses two-stage atomization to create tiny particles, allowing for precise control of liquid dispensing and distribution, enabling efficient and uniform coating on various objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air atomization spray is used to form thin films, then particle diameter can be reduced to 10 μm or smaller, but coating efficiency falls to 30% or less and film thickness precision deteriorates to ±10% or more
Solution Approach 1:
The invention divides the single atomization process into two stages: first atomization (creating initial fine particles) and second atomization (further refining particles and forming eddy flow). This segmentation allows each stage to be optimized independently, achieving both fine particle diameter (10 μm or smaller) and high coating efficiency (80% or higher) while improving film thickness precision to ±5% or less.
Solution Approach 2:
The invention introduces a second atomization compressed gas as an intermediary medium to further process the liquid particles after first atomization. This second gas stream acts as a mediator that refines the particle size and creates the eddy flow pattern, enabling precise control of particle diameter and coating distribution without sacrificing coating efficiency.
2Manufacturing precision
If atomization air pressure is increased to 0.4 MPa or higher to make particle diameter 10 μm or smaller, then finer particles are achieved, but particles adhere to the coated object unevenly and coating efficiency falls to 30% or less
Solution Approach 1:
The atomization process is segmented into two pressure-staged processes: first atomization at a lower pressure (0.05-0.3 MPa) for gentle initial particle formation, and second atomization at a controlled pressure (0.05-0.5 MPa) for final particle refinement. This segmentation prevents the adverse effects of excessive single-stage pressure while achieving the desired 10 μm or smaller particle diameter with uniform adhesion.
Solution Approach 2:
The invention changes the pressure parameter from a single high-pressure input to a two-stage pressure sequence, with each stage operating within an optimized pressure range. This parameter transformation allows precise control of particle diameter and adhesion characteristics while maintaining high coating efficiency.
3Productivity
If spray nozzle is positioned close to the coated object to achieve high coating efficiency, then coating efficiency reaches 80% or higher, but it is difficult to control small amounts or very small amounts dispensed
Solution Approach 1:
The invention employs a dynamic control mechanism where the needle moves along the inner wall of the nozzle to precisely regulate the liquid flow passage area. This dynamic adjustment capability allows accurate control of dispensing amounts (0.1-10 cm³/min) even when the nozzle is positioned close to the coated object for high coating efficiency (80% or higher).
Solution Approach 2:
The invention replaces manual skill-based control with a mechanical needle-positioning system that automatically controls the liquid flow passage. The needle's position along the nozzle wall mechanically adjusts the dispensing amount, eliminating the need for operator skill while maintaining high coating efficiency through close nozzle-to-object positioning.
4Manufacturing precision
If liquid viscosity is reduced to 20 CPS or lower to form particles of 10 μm and smaller, then particle diameter is reduced, but at a location 300 mm or farther from the spray exhaust exit only about 20% of the entire dispensed amount is formed
Solution Approach 1:
The invention segments the atomization into two stages with different viscosity requirements: first atomization handles the liquid at reduced viscosity (20 CPS or lower) to create initial fine particles, while second atomization further refines these particles. This segmentation maintains fine particle diameter (10 μm or smaller) while the eddy flow from second atomization improves material distribution, forming 80% or more of the dispensed amount even at distances of 300 mm or farther.
5Manufacturing precision
If spin coater or bar coater is used on flat surfaces, then film formation works well, but on uneven surfaces the coating material may fly off and on spherical or cylindrical objects it is difficult to form a film
Solution Approach 1:
The invention uses pneumatic atomization (compressed gas) instead of mechanical contact methods like spin coating or bar coating. The atomized liquid particles are delivered via gas flow to the coated object, allowing uniform coating on uneven surfaces, spherical objects, and cylindrical objects without the coating material flying off or the inability to coat complex geometries.
Solution Approach 2:
The invention changes the application method from mechanical contact (spin/bar coating) to pneumatic delivery of atomized particles. This parameter change in the application mechanism enables versatile coating on various surface types while maintaining film formation quality, as the atomized particles can reach all surfaces including uneven, spherical, and cylindrical geometries.
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 device achieves high coating efficiency and precise film thickness control, forming thin films with improved uniformity and reproducibility on complex surfaces without manual skill requirements, maintaining coating efficiency and precision.
Implementation Method 1
liquid oozes from the first nozzle hole of the first nozzle along the needle tip part, and is made into tiny particles by the first atomization compressed gas flowing through the first atomization compressed gas passage and exhausts from the second nozzle hole of the second nozzle
Implementation Method 2
the second atomization/eddy flow formation compressed gas exhausts from the third nozzle hole of the third nozzle, so the exhaust flow is made into even smaller particles
Data Source
AI summary
A spray device includes an opening gap between a needle-shaped needle tip and a first nozzle hole. The gap is adjusted by a very tiny amount by a needle movement amount adjustment device, and liquid oozes from the first nozzle hole along the needle tip part. The liquid is formed into tiny particles by a first atomization compressed gas flowing through the first atomization compressed gas passage and is exhausted from a second nozzle hole. The exhaust flow passes through a third nozzle hole and is exhausted. The third nozzle's second atomization/eddy flow formation compressed gas collides with this exhaust flow, so the exhaust flow is made into even smaller particles, and swirls and disperses, and is applied to the coated object.