Stimulation Lead Wire Wrapping Die for Residual Stress Control
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Solution Overview
Problem
The complex process of manufacturing stimulation leads for neurostimulation systems, particularly in wrapping conductor wires around a core material, often results in residual stress and deformation due to uneven winding tension, which can affect the consistency and durability of the final product.
Innovation Solution
A system comprising a payout assembly, take-up assembly, turntable, and a die with asymmetric features that control the wrapping of conductor wires in an axially repeating pattern with controlled tension and back twist compensation, ensuring consistent spacing and minimizing residual stress during the wrapping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wire wrapping methods are used to manufacture stimulation leads, then the manufacturing process can be completed, but residual stress and deformation occur due to uneven winding tension
Solution Approach 1:
The die is segmented into multiple opening sections that can be independently adjusted, allowing each section to control the spacing of wire groups separately. This segmentation enables precise control over wire placement patterns, creating consistent spacing between wire groups while reducing uneven tension distribution during the wrapping process.
Solution Approach 2:
The die preforms the wires as they pass through its opening sections before the wires are wrapped around the core. This preliminary shaping action ensures wires are properly positioned and tensioned in advance, preventing deformation and residual stress that would occur during the wrapping process.
2Shape
If wires are wrapped tightly around the core, then the lead structure is maintained, but residual stress accumulates affecting the final product consistency
Solution Approach 1:
The die creates local variations in wire spacing by defining specific opening sections for groups of wires. This local quality control allows certain wire groups to be closely spaced while other groups are separated by larger distances, creating a controlled repeating pattern that maintains lead shape while distributing stress uniformly.
Solution Approach 2:
The die opening sections are asymmetrically arranged to create a repeating pattern of closely spaced wire groups separated by larger gaps. This asymmetric arrangement prevents uniform stress distribution that would occur with evenly spaced wires, thereby reducing residual stress while maintaining consistent lead profile.
3Stability of the object's composition
If force is applied to permanently deform wires to maintain wrapping, then wires stay in position, but the manufacturing process becomes complex requiring additional equipment
Solution Approach 1:
The die is extracted from complex preforming equipment and integrated directly into the wrapping system. By incorporating the preforming function into the existing die structure, the system eliminates the need for separate wire deformation equipment, reducing overall system complexity while maintaining wire position stability.
Solution Approach 2:
The die serves multiple functions: it guides wires, preforms them, controls spacing, and maintains tension all in a single component. This multi-functionality eliminates the need for multiple separate devices, simplifying the manufacturing system while ensuring stable wire positioning throughout the wrapping process.
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 approach allows for the fabrication of stimulation leads with reduced residual stress, enabling elastic elongation and maintaining the original shape and profile, even after stretching forces are applied, thus enhancing the durability and consistency of the lead bodies.
Implementation Method 1
force is applied to the wires as the wires are served onto the mandrel to permanently deform or 'preform' the wires to maintain the wires around the mandrel when the winding tension is released
Implementation Method 2
conductor wires are let out in controlled manner by a plurality of 'payout carriers.' The plurality of payout carriers are rotated as a group about the mandrel
Data Source
AI summary
In one embodiment, a system for wrapping biomedical conductor wires about core material, comprises: a payout assembly and a take-up assembly for controllably paying out the core material and taking up the core material with the wrapped conductor wires; a turntable; a plurality of carriers, disposed on the turntable, for letting out the conductor wires; and a die for applying force to the conductor wires as the wires are wrapped about the core material, the die adapted to rotate according to group rotation of the plurality of carriers by the turntable during operation of the system, wherein the die comprises one or more features asymmetrically arranged about a circumference of the die, the one or more features adapted to direct the conductor wires from the plurality of carriers onto the core material in an axially repeating pattern of groups of closely spaced wires with each group separated by a distance larger than the spacing between adjacent wires within each group.