Closed Loop Filament Stent Braiding
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Solution Overview
Problem
Existing stents face challenges in uniformity and safety due to irregular wire distances and difficulties in welding exposed end portions, especially with fine filaments, which can lead to damage during implantation.
Innovation Solution
A stent with a hollow tubular structure formed by alternately woven closed-loop filaments, where both ends are connected to guide lines to prevent sharp edges and facilitate pre-welding, allowing for uniformity and safety through braiding and heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a braiding apparatus is used to produce stents, then productivity is improved, but the end portions have exposed metal filaments requiring additional welding processes
Solution Approach 1:
The patent applies preliminary action by pre-welding the metal filaments into closed loops before the braiding process. This eliminates the need for post-braiding welding of exposed end portions, resolving the manufacturing complexity issue while maintaining high productivity through automated braiding.
Solution Approach 2:
The patent discards the conventional approach of leaving end portions exposed and instead recovers the metal filaments by welding them into closed loops. This eliminates the harmful exposed ends that require additional welding processes, solving both the productivity and manufacturing ease contradiction.
2Ease of operation
If fine filaments with small diameter are used, then stent flexibility is improved, but welding of end portions becomes almost impossible
Solution Approach 1:
The patent performs the welding action preliminarily, before the filaments are braided into the final stent structure. By welding fine filaments into closed loops while they are still accessible and manageable, the patent overcomes the welding infeasibility of fine filaments while preserving the flexibility benefits of using thin-diameter materials.
Solution Approach 2:
Instead of welding after braiding (the conventional approach), the patent inverts the sequence by welding before braiding. This reversal makes welding of fine filaments feasible while maintaining the desired stent flexibility, resolving the contradiction between ease of operation and ease of manufacture.
3Object-affected harmful factors
If beads are welded at the ends of filaments, then sharp tip exposure is prevented, but welding of fine particles to fine filaments is difficult
Solution Approach 1:
The patent extracts the welding operation from the post-braiding stage and performs it separately on the filaments before braiding. This separation allows for proper welding of fine filaments into closed loops without the complexity of welding beads to fine filaments after braiding, preventing sharp tip exposure while maintaining manufacturing ease.
Solution Approach 2:
The patent applies preliminary action by creating closed-loop structures from the filaments before the braiding process. This preliminary formation of closed loops eliminates sharp exposed ends without requiring difficult bead welding operations on fine filaments, resolving the contradiction between safety and manufacturing ease.
4Manufacturing precision
If hand-made stents are produced, then uniform characteristics are difficult to achieve, but productivity is significantly low
Solution Approach 1:
The patent applies preliminary action by pre-welding filaments into closed loops with precise, uniform dimensions before braiding. This preliminary precision work, combined with automated braiding, achieves uniform stent characteristics while maintaining high productivity, resolving the contradiction between manufacturing precision and productivity.
Solution Approach 2:
The patent replaces the hand-made mechanical process with an automated system that performs preliminary welding and subsequent braiding. This substitution enables consistent, uniform stent characteristics to be produced at high rates, resolving the contradiction between manufacturing precision and productivity.
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
The solution ensures uniform stent characteristics and safety by preventing sharp edges and enabling easier manufacturing, allowing for improved self-expandability and drug delivery capabilities while minimizing adverse interactions with blood vessels.
Implementation Method 1
Each of the filaments has at least one elongated closed-loop wire
Implementation Method 2
a stent which is self-expandable
Data Source
AI summary
Disclosed is a stent having a hollow tubular structure with open ends which tubular structure is formed by a plurality of filaments woven alternately, wherein each of the filaments has at least one elongated closed-loop wire and both ends of each of the filaments are positioned at the open ends, and a method for fabricating the stent.