Crimping Tool Mandrel and Collars for Stent Graft Uniformity
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Solution Overview
Problem
The unpredictable behavior of excess fabric in stent grafts during compaction and deployment due to non-uniform crimping methods, which can lead to misalignment of fenestrations and interference with guide wires or other components.
Innovation Solution
A crimping tool with a mandrel and collars featuring chamfered abutment faces and ends, used in conjunction with a method of forming crimps by sliding the mandrel into an aperture, folding the fabric over collars, and heat-setting to create uniform crimps or pleats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If axial compression is applied to a tubular or cone-shaped device to obtain crimps or pleats, then the device can be compacted, but uniformity of the pleats is difficult to achieve
Solution Approach 1:
The crimping tool is divided into multiple collars (first collar, second collar, third collar) that can be independently positioned on the mandrel. Each collar creates a separate crimping zone, allowing individual control over the formation of pleats in different sections of the fabric, thereby achieving uniformity while maintaining compactness
Solution Approach 2:
Each collar is designed with specific dimensions and positioning to create crimps of uniform quality in localized regions. The collars have different outer diameters and are spaced at specific intervals, ensuring that each crimping zone produces consistent pleats tailored to the local requirements of the stent graft
2Adaptability or versatility
If excess fabric is provided in the adjustment region to allow fenestration position adjustment, then adaptability to different patients is improved, but unpredictable behavior during compaction and deployment occurs
Solution Approach 1:
The excess fabric in the adjustment region is pre-crimped using the multi-collar tool before the stent graft is deployed. This preliminary crimping action stabilizes the fabric structure in advance, ensuring that when the device is compacted and deployed, the fabric behaves predictably and the fenestration remains properly aligned, thus resolving the contradiction between adaptability and reliability
3Adaptability or versatility
If excess material is present in the adjustment region, then fenestration alignment flexibility is improved, but interference with guide wires or other stenting components may occur
Solution Approach 1:
The excess fabric is crimped in advance using the multi-collar tool, which consolidates and stabilizes the fabric structure before deployment. This preliminary action ensures that the crimped fabric does not unfold or shift during subsequent procedures, preventing interference with guide wires or other stenting components while maintaining the necessary flexibility for fenestration alignment
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
Ensures uniformity and predictability of crimps or pleats, enhancing the compactness and deployment behavior of stent grafts, thereby improving the alignment of fenestrations and reducing interference with other components.
Implementation Method 1
apply axial compression to a tubular or cone-shaped device in order to obtain the desired crimps or pleats
Implementation Method 2
the excess material may fold in one direction and in another instance it may fold in a different direction
Implementation Method 3
heat setting the fabric whilst trapped between the abutment face and first and second collars
Data Source
AI summary
A crimping tool is provided, where the tool comprises a mandrel (1) having a first portion (3) with a first outer diameter, and a second portion (5) with a second outer diameter which is greater than the first outer diameter. A chamfered abutment face (7) is provided between the first and second portions (3,5). At least one first collar (9) is mountable on the first portion (3) of the mandrel (5) and has a chamfered first end (11) which in use abuts the abutment face (7). At least one second collar (13) is mountable on the second portion (5) of the mandrel (1) and has a chamfered second end (15) which in use abuts the first end (11) of the first collar (9). A method of using the tool to form one or more crimps in a piece of fabric is also disclosed.