EDM Fixation Helix Fixturing for Precise High-Volume Lead Manufacturing
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Solution Overview
Problem
Current manufacturing techniques for active fixation implantable medical leads, particularly the fixation helix, face challenges in achieving precise and high-volume production, leading to imperfections such as non-flat proximal ends and misaligned profiles that affect the performance and functionality of the helix.
Innovation Solution
A novel fixture system comprising two interlocking members with semi-circular recesses and planar surfaces, aligned to secure workpieces for machining using a wire electrical discharge machine (EDM), ensuring precise machining of the fixation helix with flat proximal ends and sharpened distal tips, facilitating high-volume production without re-tooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional manufacturing techniques are used for fixation helix, then production volume can be increased, but manufacturing precision deteriorates resulting in non-flat proximal ends and misaligned profiles
Solution Approach 1:
The fixture is divided into multiple members (first fixture member, second fixture member) that can be selectively assembled and disassembled. Each member has specific features (semi-circular recesses, planar surfaces, fastener holes) that work together to provide precise positioning. This segmentation allows the fixture to be configured for different production needs while maintaining precision.
Solution Approach 2:
The fixture members are pre-configured with semi-circular recesses and planar surfaces that automatically position the fixation helix workpiece in the correct orientation before machining begins. The proximal end positioning feature and distal end support feature are built into the fixture structure, ensuring consistent positioning without requiring manual adjustment during high-volume production.
2Manufacturing precision
If precise machining of fixation helix is achieved, then manufacturing precision is improved, but device complexity increases due to specialized fixture requirements
Solution Approach 1:
The fixture members are designed with multiple features that serve different functions: semi-circular recesses for positioning, planar surfaces for support, fastener holes for assembly, and alignment features for precision. This multi-functionality reduces the need for multiple specialized fixtures, simplifying the overall device complexity while maintaining manufacturing precision.
Solution Approach 2:
The fixture members feature asymmetric design elements such as semi-circular recesses rather than circular holes, and specific planar surface orientations that match the asymmetric geometry of the fixation helix workpiece. This asymmetric configuration provides precise positioning while using simple geometric forms that are easy to manufacture.
3Productivity
If high-volume production is implemented, then productivity increases, but manufacturing precision deteriorates due to tool wear and fixture wear requiring frequent re-tooling
Solution Approach 1:
The patent employs wire electrical discharge machining (EDM) instead of conventional mechanical machining methods. This substitution eliminates mechanical contact between the cutting tool and the fixation helix, preventing tool wear and fixture wear that would otherwise accumulate during high-volume production. The electrical discharge process maintains consistent precision throughout the production run without requiring frequent re-tooling.
Solution Approach 2:
The fixture members are designed to be selectively assembled and disassembled without requiring specialized tools or complex procedures. The fastener holes and alignment features enable operators to quickly reconfigure or replace fixture members as needed, allowing the system to maintain precision through easy maintenance rather than through inherently wear-resistant materials or designs.
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
The solution enables precise and efficient manufacturing of fixation helices with consistent flat proximal ends and sharpened distal tips, enhancing the performance and functionality of active fixation implantable medical leads by improving tissue holding and mechanical attachment, while allowing for high-volume production without the need for frequent re-tooling.
Implementation Method 1
machining each workpiece using an EDM process to form a finished fixation helix
Data Source
AI summary
An apparatus for use in manufacturing a component of an implantable medical device comprises a fixture comprising a first fixture member having a plurality of semi-circular recesses in a lower surface thereof, and a second fixture member having a plurality of semi-circular recesses in an upper surface thereof, the first and second fixture members being configured to be selectively fastened together via a plurality of fasteners, wherein in an assembled state of the fixture, each of the semi-circular recesses of the first fixture member lower surface is aligned with an opposing semi-circular recess in the second fixture member upper surface to define a plurality of workpiece openings each dimensioned to receive and secure a respective work piece to be machined to the fixture.