Atraumatic Braided Stent Manufacturing With Controlled Braiding Angles
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Solution Overview
Problem
Existing braided stents face issues with variations in braiding angle and material waste, particularly when using expensive materials like nitinol, leading to inconsistent stent configurations and increased costs.
Innovation Solution
The use of braiding mandrels with specifically designed grooves and projections, combined with constant force braiding carriers, allows for controlled braiding angles and efficient use of discrete wire lengths to produce atraumatic stents with consistent specifications, minimizing material waste and optimizing manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wire is fed from a spool onto the mandrel during braiding, then multiple stents can be formed continuously, but excess wire material is wasted and trimmed after braiding
Solution Approach 1:
The patent applies preliminary action by pre-cutting the wire into specific lengths before braiding begins. The wire is cut to match the exact mandrel circumference plus minimal excess, so that after braiding, the wire ends align perfectly with the mandrel end without requiring trimming. This eliminates material waste while maintaining continuous production capability.
Solution Approach 2:
The patent changes the wire feeding parameter from continuous spool feeding to discrete pre-cut length feeding. By adjusting the wire length parameter to precisely match the mandrel dimensions, the system eliminates excess material generation while maintaining production efficiency.
2Strength
If metallic wires are used in braiding, then stents can be formed with structural strength, but wires may shift or move during braiding resulting in variation of braiding angle
Solution Approach 1:
The patent introduces an intermediary element - a mandrel with circumferential grooves - that mediates between the wire and the braiding process. The grooves act as guides that constrain wire movement and maintain consistent braiding angles, while the wire retains its structural strength properties in the final stent.
Solution Approach 2:
The mandrel with grooves provides self-service by automatically guiding the wire placement and maintaining braiding angle consistency throughout the process, eliminating the need for external monitoring or adjustment mechanisms.
3Ease of manufacture
If wires are gathered beyond the mandrel end and secured by tying or taping, then braiding can commence, but the ends are not atraumatic and require additional securing steps
Solution Approach 1:
The patent applies preliminary action by pre-forming the wire ends into loops or bends before braiding begins. These pre-formed ends are designed to be atraumatic and self-containing, eliminating the need for post-braiding tying or taping operations.
Solution Approach 2:
The patent extracts the harmful securing steps (tying or taping) from the manufacturing process by redesigning the wire ends to be self-containing and atraumatic, eliminating the need for additional securing operations.
Data Source
AI summary
A method of braiding a stent includes braiding a number of elongate filaments around a mandrel using tensioned braiding carriers without spooling the filaments to the tensioned braiding carriers to form a braided stent having atraumatic ends.