Grooved Vacuum Coupling for Magnetron Sputtering
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Solution Overview
Problem
Existing coupling systems for cylindrical targets in magnetron sputtering systems face issues with misalignment, high stress concentrations, and water leaks due to screw-based fixation methods, leading to premature failure and increased downtime for target replacement.
Innovation Solution
A coupling system featuring a spindle with a flange portion and a cylindrical target with multiple separate circular grooves that engage with an interface ring, allowing for easy alignment and stress distribution, along with a clamping mechanism to secure the target without screw fixation, ensuring a watertight seal and easy attachment/detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a threaded spindle collar with screw movement is used to fix the target to the spindle, then the target can be securely attached, but misalignment between the target and spindle occurs leading to reduced coupling life and sealing issues
Solution Approach 1:
The patent replaces the threaded screw fixation system with a groove-based mechanical interlocking system. The interface ring engages with circular grooves on the target end portion through radial movement, eliminating the screw movement mechanism that caused alignment issues. This substitution maintains secure attachment while enabling precise alignment through simple radial insertion rather than rotational threading.
2Device complexity
If a single helical or circular groove is used for coupling, then the structure is simple, but stress concentration occurs leading to premature failure
Solution Approach 1:
The patent divides the single groove structure into multiple separate circular grooves (typically three) arranged circumferentially on the target end portion. The interface ring correspondsingly has multiple engagement surfaces that interact with these grooves. This segmentation distributes the mechanical stresses across multiple contact points rather than concentrating them in a single groove, significantly improving stress resistance while maintaining relatively simple overall structure.
3Strength
If a threaded coupling system is used, then the target can be firmly fixed, but water leaks occur at the interface between the spindle and target
Solution Approach 1:
The patent introduces an interface ring as an intermediary component between the target and the spindle/clamping mechanism. This interface ring serves multiple functions: it engages with the circular grooves to provide mechanical fixation, provides a sealing surface to prevent water leakage, and distributes clamping forces evenly. The intermediary interface ring thus simultaneously achieves firm fixation and leak prevention that were problematic in direct threaded coupling systems.
4Adaptability or versatility
If a clamp and retaining ring system is used to affix the target, then non-threaded targets can be mounted, but stress concentration in the groove area remains unacceptably high
Solution Approach 1:
The patent applies the segmentation principle by using multiple circular grooves instead of a single groove for the clamp and retaining ring system to engage. This multi-groove configuration distributes the clamping stresses across several contact points around the circumference of the target, significantly reducing stress concentration in any single groove area while maintaining the versatility of mounting non-threaded targets.
Data Source
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AI summary
The present invention relates to a coupling system (10) to releasably clamp a cylindrical target (12) to a spindle (14) by means of an interface ring (22) and a clamping ring (26), whereby the interface ring (22) and the cylindrical target (12) have engaging surfaces comprising two or more circular grooves (18). In another embodiment the clamping ring and the interface ring are the same piece. The advantage of the present coupling system is that it allows a square fitting and avoids high mechanical stresses.