Woven Stent Strand End Coupling for Secure Nickel-Titanium Joining
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Solution Overview
Problem
Existing medical devices, such as stents and occluders, face challenges in securely joining strand ends made of nickel-titanium materials, particularly in maintaining structural integrity and consistency during insertion and expansion within anatomical structures.
Innovation Solution
The use of coupling structures, which are welded to the strand ends using laser welding, ensuring alignment and secure connection while maintaining the material's properties, with the length of the coupling structure being a fraction of the device's length, and positioned to define specific strand crossings that enhance the device's structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coupling structures are welded to strand ends using laser welding, then structural integrity and secure connection are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The device is divided into distinct components (strands, coupling structures, welded regions) that can be independently analyzed and manufactured. The coupling structures are separate elements that join strand ends, creating discrete secured regions rather than continuous welding along the entire strand length.
Solution Approach 2:
Welding is applied locally only at specific coupling regions where strand ends need to be joined, rather than along the entire length of the strands. This concentrates the structural reinforcement where needed while leaving the majority of the strands in their original state, maintaining flexibility and reducing overall complexity.
2Manufacturing precision
If coupling structures are used to secure strand ends, then securement consistency is improved, but the length of the device increases
Solution Approach 1:
The coupling structures extend slightly beyond the minimum required to secure the strand ends, ensuring consistent securement with adequate overlap and welded region formation. This partial excess in coupling structure dimensions guarantees reliable joining while the overall added length remains controlled and minimal relative to the total device length.
3Strength
If strand ends are welded to coupling structures, then structural stability is improved, but material properties may be altered
Solution Approach 1:
The laser welding process parameters (power, speed, pulse duration) are carefully controlled and optimized to achieve adequate welding strength while minimizing heat input to the nickel-titanium strands. This prevents unwanted phase transformations or microstructural changes in the shape memory alloy, preserving its elastic and superelastic properties in the welded regions while maintaining structural stability.
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 provides a robust and consistent securement of strand ends, allowing for effective deployment and expansion of medical devices within anatomical structures, maintaining structural integrity and ensuring uniform strand bend configurations.
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
A woven, self-expanding stent device has one or more strands and is configured for insertion into an anatomical structure. The device includes a coupling structure secured to two different strand end portions that are substantially aligned with each other. The two different strand end portions include nickel and titanium. The coupling structure is not a strand of the device.