Replaceable Shield for Atmospheric Plasma Coating
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Solution Overview
Problem
Existing atmospheric plasma coating techniques are not suitable for in-line coating of continuous substrates with irregular surfaces, nor do they allow for easy cleaning, long-term maintenance, or coating of non-metallic substrates like plastic and glass with low melting temperatures.
Innovation Solution
A method and apparatus for atmospheric pressure plasma coating using a replaceable shield with a nozzle outlet edge congruent to the object profile, allowing for in-line coating of all types of substrates with a low-temperature, oxygen-free plasma at slightly higher than atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature plasma spray techniques are used to coat substrates, then coating material particles are softened for enhanced coating adhesion, but substrates with low melting temperatures (below 1000°C, especially below 200°C) cannot be coated without damage
Solution Approach 1:
The invention changes the temperature parameter of the plasma from high temperature (1000°C or more) to low temperature (below 200°C, preferably below 100°C). This is achieved by using a dielectric barrier discharge plasma jet instead of conventional high-temperature plasma spray, allowing coating of temperature-sensitive substrates while maintaining coating adhesion through chemical activation of the plasma
Solution Approach 2:
The invention utilizes the phase transition properties of coating materials by providing them in vapor or aerosol form rather than solid particles. The coating material is deposited in a condensed phase directly onto the substrate, eliminating the need for high-temperature softening of particles while ensuring proper adhesion through controlled condensation
2Productivity
If atmospheric pressure plasma coating is performed without a shield, then the process can be performed in-line without vacuum chambers, but ambient air enters the plasma zone causing oxidation and poor coating quality
Solution Approach 1:
The invention introduces a shield as an intermediary component between the plasma jet generator and the substrate. The shield creates a controlled atmosphere zone that prevents ambient air from reaching the plasma-activated substrate surface, eliminating oxidation while allowing atmospheric pressure operation. The shield acts as a physical barrier that mediates between the plasma process and ambient environment
Solution Approach 2:
The shield creates an inert or controlled atmosphere environment within the coating zone by preventing ambient air ingress. This allows the plasma process to proceed at atmospheric pressure while maintaining conditions suitable for high-quality coating deposition, combining the advantages of atmospheric pressure operation with protected atmosphere benefits
3Device complexity
If a fixed nozzle design is used for plasma coating, then the apparatus structure is simple, but it cannot accommodate substrates of different shapes and sizes
Solution Approach 1:
The invention makes the nozzle system dynamic and adaptable by allowing the shield to be adjusted or replaced based on substrate requirements. The shield geometry can be modified to match different substrate shapes, and the plasma jet parameters can be dynamically adjusted to accommodate various coating scenarios, transforming a static nozzle design into a flexible system
Solution Approach 2:
The invention segments the nozzle system into modular components, particularly the shield, which can be independently adjusted or replaced. This segmentation allows different shield configurations to be used for different substrate types while maintaining a common plasma jet generator, reducing overall system complexity while increasing versatility
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
Enables homogeneous coating on various substrates, including metallic and non-metallic ones, with improved adhesion and stability, and allows for easy replacement of shields for different substrate shapes and sizes.
Implementation Method 1
providing a plasma jet in the shield via the plasma jet generator
Implementation Method 2
plasma coating the object with a low-temperature, oxygen-free plasma at an operating pressure which is higher than the atmospheric pressure
Implementation Method 3
providing a plasma jet in the shield via the plasma jet generator and injecting coating precursors in the plasma jet in the shield, thereby creating an overpressure in the shield with respect to the environment
Implementation Method 4
the nozzle outlet comprises an edge essentially congruent to at least part of the object profile, preferably by manufacturing said replaceable shield
Data Source
AI summary
A plasma coating an object has an object profile, and includes the steps of: providing a replaceable shield including a jet inlet, a nozzle outlet and a sidewall extending from the jet inlet to the nozzle outlet; detachably attaching the replaceable shield to a jet outlet of a plasma jet generator; placing the object at the nozzle outlet such that the object profile fits closely to the nozzle outlet edge to within a distance of at least 0.1 mm and at most 5 mm; plasma coating the object with a low-temperature, oxygen-free plasma at an operating pressure which is higher than the atmospheric pressure by providing a plasma jet in the shield via the plasma jet generator and injecting coating precursors in the plasma jet in the shield; identifying the provided shield prior to providing the plasma jet.