Simultaneous Brazing of Ferrule and Lead Pins Using Alignment Fixture
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Solution Overview
Problem
Existing methods for making feedthrough interconnects, particularly in medical devices, face challenges in efficiently and accurately aligning and brazing ferrules to ceramic insulators and lead pins, leading to potential errors and inconsistencies in forming reliable electrical connections within hermetically sealed devices.
Innovation Solution
A method involving a freestanding lead pin fixture that aligns and fixes lead pins with braze preforms to contact pads on a ceramic insulator, allowing simultaneous brazing of the ferrule to the insulator and lead pins, using a lead pin fixture with holes and a feedthrough insertion cutout, and heating the assembly to form robust brazed joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional separate brazing methods are used for ferrule to insulator and lead pins to pads, then each joint can be formed individually, but the process time increases and alignment accuracy decreases
Solution Approach 1:
The patent combines multiple brazing operations into a single simultaneous brazing process. The ferrule is brazed to the insulator while the lead pins are brazed to their respective pads in one heating cycle, eliminating the need for separate brazing steps and improving both time efficiency and alignment consistency
Solution Approach 2:
The lead pins are pre-positioned in the ferrule using a fixture before the brazing process begins. This preliminary alignment ensures that when simultaneous brazing occurs, all components are already in their correct positions, eliminating alignment errors that would occur with sequential positioning
2Manufacturing precision
If manual alignment methods are used for lead pins and contact pads, then flexibility is maintained, but repeatability and precision of alignment deteriorate
Solution Approach 1:
A specialized fixture serves as an intermediary tool between the operator and the components. The fixture contains precisely machined features that guide lead pins into correct alignment with contact pads and holds the ferrule in position, providing repeatable alignment without requiring complex manual manipulation
Solution Approach 2:
The fixture is designed to self-align components through its built-in geometric features. The lead pin holes and ferrule positioning features are machined to precise tolerances that automatically guide components into correct positions when assembled, eliminating the need for complex adjustment mechanisms
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 enables repeatable and efficient formation of reliable brazed joints between the ferrule, ceramic insulator, and lead pins, ensuring consistent electrical connections and allowing for the production of multiple feedthrough assemblies simultaneously with high precision.
Implementation Method 1
simultaneously brazing a ferrule to an insulator and lead pins to pads on the insulator using braze preforms
Implementation Method 2
heating the feedthrough assembly at a temperature and for a time sufficient to form brazed joints
Data Source
AI summary
A lead pin fixture is used to align and hold lead pins in place for brazing lead pins to metal contact pads of a ceramic insulator and brazing a ferrule to the ceramic insulator in a single step.