EB-PVD Tooling for Uniform Coating of Multiple Workpieces
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Solution Overview
Problem
Electron Beam Physical Vapor Deposition (EB-PVD) processes face challenges in uniformly coating irregularly shaped workpieces and multiple workpieces due to issues with vapor cloud edges and overlapping vapor plumes, leading to irregular or uneven coating applications.
Innovation Solution
The use of tooling such as shields and crucibles with specific configurations within a deposition chamber to optimize heating and prevent overlap of vapor clouds, combined with controlled deposition chamber pressures and crucible shapes to achieve uniform coating, ensures each workpiece receives a dedicated vapor plume for consistent deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple workpieces are coated in a chamber with multiple feedstocks, then productivity increases, but coating uniformity deteriorates due to overlapping vapor plumes
Solution Approach 1:
The deposition chamber is divided into multiple separate deposition zones, each with its own feedstock source and isolated vapor plume. Physical barriers and spatial arrangement prevent vapor plume overlap, allowing each workpiece to receive uniform coating from its dedicated feedstock while multiple workpieces are processed simultaneously in different zones.
2Productivity
If feedstocks are distributed throughout the chamber to coat multiple workpieces, then productivity increases, but coating precision deteriorates due to irregular vapor cloud edges
Solution Approach 1:
Each deposition zone is configured with localized heating and vapor generation specifically tailored to the geometry and coating requirements of the workpiece in that zone. The vapor plume characteristics, heating power, and feedstock delivery are optimized locally for each workpiece position, ensuring uniform coating thickness control despite processing multiple different workpieces simultaneously.
3Productivity
If vapor plumes are allowed to overlap to increase coating coverage, then productivity improves, but coating quality deteriorates due to irregular deposition
Solution Approach 1:
The harmful overlapping effect is eliminated by extracting or removing the vapor plumes from each other's space through physical barriers and zone isolation. Each vapor plume is confined to its designated deposition zone, preventing interaction with other plumes while maintaining full coverage of the assigned workpiece area, thus preserving coating regularity.
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 approach enables predictable and uniform coating of multiple and complex workpieces, maintaining coating quality and consistency even under varying vacuum conditions, reducing the likelihood of irregular deposition thickness and overlapping vapor plumes.
Implementation Method 1
Vaporized material for deposition can be generated by energizing feedstock material which can be retained in a conductive crucible
Implementation Method 2
Electron Beam Physical Vapor Deposition (EB-PVD) processes and apparatus utilize a cloud of vaporized material which is solidified upon at least one workpiece surface
Implementation Method 3
a cloud of vaporized material which is solidified upon at least one workpiece surface in a deposition chamber
Data Source
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AI summary
An embodiment of an apparatus (10) includes a first crucible (72A;200;250;300) in communication with a deposition chamber (18), an energy source (68A), and a workpiece fixture (20). The first crucible (72A;200;250;300) includes a plurality of walls (110) defining an upper recess (210;260;310) and a first lower recess (212;262,312), at least the upper recess (210;260;300) open to an interior of the deposition chamber (18). The energy source (68A) is configured to selectively apply and direct energy (69A) within the deposition chamber (18), including toward the first crucible (72A;200;250;300). The workpiece fixture (20) includes tooling (78) and a plurality of workpiece holders (67) configured to retain at least one workpiece (22) selectively within the deposition chamber (18). The tooling (78) includes at least one wall (80) separating at least a first of the plurality of workpiece holders (67A) from a second of the plurality of workpiece holders (67B).