Stent Strand End Welding Using Coupling Structures for Axial Integrity
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Solution Overview
Problem
Existing medical devices, such as stents, face challenges in securely joining strand ends made of nickel-titanium materials, particularly in maintaining structural integrity and consistency across device ends, especially when subjected to axial compression.
Innovation Solution
The use of coupling structures that are welded to strand end portions, with the coupling structure being positioned in direct contact before welding, and configured to form separate welded regions without direct connection, ensuring alignment and stability while allowing for axial offset or alignment along the device's longitudinal axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If coupling structures are welded to strand end portions to secure them, then structural integrity is improved, but device complexity increases due to additional components and welding processes
Solution Approach 1:
The device is divided into distinct components: strand portions, coupling structures, and welded regions. This segmentation allows each component to be optimized independently while maintaining overall structural integrity through controlled joining points.
Solution Approach 2:
The coupling structure serves as an intermediary element between strand end portions, providing a controlled interface for joining. This mediator enables secure connection while managing the complexity of the welding process by standardizing the joining mechanism.
2Manufacturing precision
If coupling structures are positioned in direct contact before welding, then manufacturing precision is improved, but ease of manufacture decreases due to stricter positioning requirements
Solution Approach 1:
The coupling structures are positioned in direct contact with strand end portions before the welding process begins. This preliminary positioning ensures precise alignment is achieved prior to welding, establishing the correct geometric relationship before permanent joining occurs.
Solution Approach 2:
The direct contact positioning method replaces more complex mechanical alignment systems. By using the coupling structure's geometry and direct contact to establish alignment, the need for additional alignment fixtures or complex positioning mechanisms is eliminated.
3Reliability
If separate welded regions are created without direct connection, then reliability is improved by isolating weld defects, but device complexity increases due to multiple discrete welding zones
Solution Approach 1:
The welded structure is segmented into separate welded regions that are not directly connected. This segmentation isolates potential defects in one welded region from affecting other regions, improving overall reliability by containing failure modes to specific localized zones.
Solution Approach 2:
Each welded region is treated as a distinct zone with its own quality characteristics. By creating separate welded regions rather than continuous welds, the patent applies local quality control to each zone, allowing defects to be isolated and managed on a regional basis rather than compromising the entire structure.
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 method enhances the structural integrity and consistency of medical devices like stents by securely joining strand ends, maintaining device shape and functionality, even under axial compression, and allows for precise control of device dimensions and welding processes.
Implementation Method 1
The securing may be accomplished by welding (e.g., laser welding) the coupling structure to the first strand end portion to create a first welded region and by welding the coupling structure to the second strand end portion to create a second welded region.
Data Source
AI summary
Methods for securing strand ends of devices configured for insertion into an anatomical structure, and the resulting devices.