Vapour Flow Control in Vacuum Evaporation
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Solution Overview
Problem
Existing methods for zinc plasma evaporation galvanization struggle with controlling zinc vapour flow, leading to zinc loss and non-uniform coating due to lack of regulation when substrates are not present, and inability to adapt to varying substrate orientations and thicknesses.
Innovation Solution
A device with movable obturation elements that can be opened or closed to control zinc vapour flow between the vapour source and the treatment zone, allowing for isolation when no substrate is present and adjusting flow according to substrate orientation and position, using a tubular passage with adjustable slats or slides to regulate vapour distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vapour source continuously evaporates coating material, then the coating process can proceed without interruption, but zinc vapour is lost when no substrate is present and contamination occurs
Solution Approach 1:
The system performs preliminary detection of substrate presence using detectors positioned to sense when a substrate enters the treatment zone. Based on this detection, the control system preliminarily adjusts the vapour flow regulation means before actual coating begins, and shuts off vapour supply in advance when substrate leaves, preventing both continuous operation waste and interruption delays
Solution Approach 2:
The system implements feedback control by using detectors to continuously monitor substrate presence and feeding this information back to the control means. The control means automatically adjusts the vapour flow regulation means based on this feedback signal, ensuring vapour is supplied only when substrate is present in the treatment zone, thus eliminating zinc vapour loss while maintaining continuous coating capability
2Manufacturing precision
If the vapour flow is increased to coat large or complex substrates, then complete coverage is achieved, but non-uniform coating occurs on substrates with varying orientations and thicknesses
Solution Approach 1:
The vapour flow regulation means is segmented into multiple independently controllable elements (such as adjustable slats or slides) positioned at different locations. Each segment can be individually adjusted based on the specific geometric requirements of the substrate, allowing differential vapour distribution across different zones to achieve uniform coating on complex geometries
Solution Approach 2:
The system applies local quality by allowing different portions of the vapour flow regulation means to have different opening degrees or flow characteristics tailored to local substrate requirements. Areas requiring more coating receive higher vapour flux while sensitive areas receive reduced flux, achieving uniform coating thickness across substrates with varying orientations and thicknesses
3Loss of substance
If the vapour source is shut off when no substrate is present, then zinc loss is minimized, but coating interruption occurs when substrate enters or leaves the treatment zone
Solution Approach 1:
The system uses detectors to detect substrate approach in advance and preliminarily opens the vapour flow regulation means before substrate enters the treatment zone. Similarly, it detects substrate departure and preliminarily shuts off vapour supply in advance, creating seamless transitions that maintain coating continuity while minimizing zinc vapour loss during transition periods
Solution Approach 2:
The system ensures continuity of useful coating action by coordinating detector signals with vapour flow regulation to maintain vapour supply throughout the entire substrate presence duration. The regulation means responds continuously to substrate position changes, ensuring no interruption in coating while avoiding waste during transition periods between substrates
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
This solution minimizes zinc vapour loss, ensures uniform coating by adapting vapour flow to substrate geometry, and prevents contamination by maintaining vapour at a controlled temperature, even when substrates are not present, thus optimizing the galvanization process.
Implementation Method 1
a source of vapour of the coating material is present and having a treatment zone communicating with the source of vapour through at least one treatment opening. The source of vapour makes it possible to generate a flow of vapour for coating a substrate.
Implementation Method 2
regulation means for controlling the flow of said vapour between the vapour source and the treatment zone through said treatment opening
Implementation Method 3
it is necessary to be able to adapt the electrical power delivered to the plasma and dissipated, via bombardment by ions issuing from the plasma, on the surface of the liquid zinc in the retention vessel
Implementation Method 4
The plasma produced in the zinc vapour is generally obtained by means of a magnetron discharge by means of a magnetic circuit disposed under the retention vessel. The zinc vapour tension above the retention vessel depends on the electrical power dissipated at the surface of the liquid zinc
Implementation Method 5
The zinc coating is therefore obtained by condensation of the zinc vapour, directly in the solid state on the cold surface of the substrate passing through the confinement enclosure. The temperature of the surface of the substrate is typically below 150° C.
Data Source
AI summary
A method and a device for the coating of running substrates moving along a run direction through a treatment zone, in which the vapor of a coating material is generated in a chamber, this vapor passing through g a treatment aperture towards the treatment zone where the coating material condenses on the surface of the substrates. The vapor flow through the treatment aperture is controlled by adjusting the extent to which the treatment aperture is shut off by at least one shutter, between an open position, in which the vapor flows through the treatment aperture towards the treatment zone, and a closed position, in which the vapor is prevented from flowing towards the treatment zone through the treatment aperture.