Stent End Smoothing via Pre-formed Waveform and Laser Trimming
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Solution Overview
Problem
The formation of stents with complex geometries, particularly those made from wound materials, is challenging due to their small size and complexity, and often results in rough edges at the ends of the stent after excess material removal.
Innovation Solution
A method involving forming a wave form from a formable material with straight and curved portions, wrapping it around a mandrel to create a helical coil, connecting adjacent curved portions to define the stent ends, and using a laser to smooth and sever the excess material, ensuring a precise and smooth finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wound stents are formed by winding source material around a mandrel and removing excess material, then the desired stent pattern and vessel support are achieved, but rough edges are created at the ends of the stent
Solution Approach 1:
The patent applies preliminary action by forming sinusoidal geometries into the source material before winding it around the mandrel. This pre-forming of the wave pattern ensures that when the stent is completed and excess material is removed, the sinusoidal structures remain intact and provide smooth transitions at the stent ends, preventing rough edges while maintaining the desired stent pattern precision
Solution Approach 2:
The patent applies local quality by creating sinusoidal geometries specifically at critical locations (the ends and transitions of the stent) rather than uniformly throughout the entire structure. This localized modification of the source material geometry provides smooth transitions where needed most, addressing the rough edge problem at stent ends without compromising the overall structural integrity or requiring uniform complexity throughout the entire stent
2Manufacturing precision
If stents with complex geometries are formed from wound materials, then precise stent patterns are achieved, but the formation process becomes difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming the sinusoidal geometries into the source material before the winding process. This allows the complex wave patterns to be created in advance using standard forming techniques, and then the pre-formed material is simply wound around the mandrel, significantly simplifying the overall manufacturing process while maintaining precise stent patterns
Solution Approach 2:
The patent applies segmentation by dividing the complex stent geometry into two separate components: the basic helical structure from winding the source material, and the sinusoidal geometries that are pre-formed into the source material itself. This segmentation allows each component to be created using optimized processes, with the sinusoidal patterns formed separately and then integrated through the winding process, reducing overall formation difficulty
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 allows for the precise formation of stents with smooth ends, overcoming the difficulty of forming complex geometries and eliminating rough edges, thereby enhancing the stent's structural integrity and support for vessel walls.
Implementation Method 1
using a laser to smooth and sever the excess material
Data Source
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AI summary
A method of forming a stent includes forming a wave form from a formable material. The wave form includes a plurality of substantially straight portions and a plurality of curved portions, each curved portion connecting adjacent substantially straight portions. The method includes wrapping the wave form around a mandrel at an angle to form a helical coil comprising a plurality of turns, connecting a first curved portion of a first turn to an adjacent second curved portion of a second turn at a position along the wave form to define an end of the stent, and removing excess material from an end of the wave form extending past the first curved portion while smoothing the end of the stent.