Mandrel Local Diameter Changes for Coil Winding Precision
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Solution Overview
Problem
Existing methods for producing in vivo indwelling members with intricately spreading three-dimensional secondary coils face challenges such as difficulty in winding and shaping primary coils around cores with small diameters, intricate grooves, and maintaining quality control, particularly for aneurysm treatment where precise sizes and shapes are required.
Innovation Solution
A method involving the formation of multiple three-dimensional bodies by winding primary coils around mandrels with specific rod-shaped portions, allowing for spatial arrangement and inside arrangement of these bodies to create an intricately spreading secondary coil shape, which can be easily produced and controlled for various sizes and shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a smooth curved surface core is used for winding the primary coil, then the shaping process becomes difficult due to coil slipping, but adding intricate grooves to improve shaping difficulty creates another problem of difficulty in fitting the coil
Solution Approach 1:
The mandrel features rod-shaped portions with locally increased diameter at specific positions rather than uniform grooves or surface features. This local quality change provides discrete anchoring points for the primary coil at critical locations (ends and intermediate positions) while maintaining a relatively simple overall cylindrical shape, solving both the slipping problem and the manufacturing complexity problem
Solution Approach 2:
The mandrel is divided into multiple rod-shaped portions with different diameter characteristics - some with increased diameter at ends, others with increased diameter at intermediate positions. This segmentation allows different sections of the primary coil to be secured by different rod portions, enabling precise control of coil shape at multiple locations along the coil length
2Ease of manufacture
If metallic rods are arranged radially on a spherical core to facilitate coil winding, then winding becomes easier, but arranging rods on small diameter cores (1-10 mm) becomes very difficult
Solution Approach 1:
Instead of arranging multiple radial rods on a spherical core (complex structure), the invention inverts the approach by using a simple cylindrical mandrel with localized diameter increases. The rod-shaped portions protrude from the cylindrical surface at specific locations, providing the necessary anchoring function without requiring a complex spherical structure with multiple radial elements
Solution Approach 2:
The invention extracts only the essential function of radial rod support by implementing localized diameter increases on a cylindrical mandrel rather than using a full spherical structure with radial rods. This takes out the core functional requirement (protruding support elements) while eliminating the unnecessary complexity of a spherical geometry and multiple radial arrangements
3Manufacturing precision
If intricate grooves are provided on the core surface to match aneurysm size, then coil fitting precision improves, but forming grooves in small diameter cores (1-10 mm) becomes very difficult
Solution Approach 1:
Rather than forming intricate grooves across the entire core surface, the invention applies local quality changes by increasing the diameter of the mandrel at specific rod-shaped portions. This provides precise fitting points for the coil at critical locations (ends and intermediate positions) without requiring complex groove formation on the entire small-diameter core surface
Solution Approach 2:
The fitting precision is achieved through segmented rod-shaped portions at different locations along the mandrel rather than continuous intricate grooves. The first rod-shaped portion secures one end of the primary coil, the second rod-shaped portion secures an intermediate position, providing segmented control points that ensure precise coil configuration without requiring complex overall groove structures
Data Source
AI summary
A method for producing an in vivo indwelling member having a secondary coil in which a secondary shape is given to a linear primary coil with a primary shape given to a linear material, includes: a first three-dimensional body formation step of forming a first three-dimensional body by aligning in a loop a plurality of segments, each of the segments being formed by winding the primary coil at least once, so that a part of the primary coil is spatially arranged; a second three-dimensional body formation step of forming a second three-dimensional body by aligning in a loop a plurality of segments, each of the segments being formed by winding the primary coil at least once, so that at least a part of the rest of the primary coil is spatially arranged after the formation of the first three-dimensional body; and an inside arrangement step of arranging one of the first and second three-dimensional bodies inside a loop part formed of the plurality of segments aligned in a loop of the other three-dimensional body.