Implantable Feedthrough Single Brazing Gold Preform
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Solution Overview
Problem
Historically, implantable medical device feedthroughs required multiple manufacturing steps due to the different thermal properties of gold and solder, leading to increased complexity, time, and cost, as well as challenges in bonding between these materials.
Innovation Solution
The use of gold components instead of solder allows for a single brazing step to secure components in the feedthrough, with capacitors metalized with niobium to promote bonding with gold, and an insulative assembly with a specific liquidus temperature to ensure secure bonding during a single heat application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If solder and gold are used together in feedthrough construction, then bonding versatility is improved, but manufacturing complexity increases due to different thermal properties requiring separate heating steps
Solution Approach 1:
The patent merges the bonding functions of solder and gold into a single gold-based brazing system. By using gold preforms with controlled composition and a single heating step, the invention eliminates the need for separate soldering and gold bonding operations, thereby reducing manufacturing complexity while maintaining bonding versatility through appropriate preform formulation
Solution Approach 2:
The patent changes the thermal parameters of the bonding process by using a single heating cycle that reaches temperatures sufficient for gold brazing (approximately 900-1100°C). This parameter change eliminates the need for multiple heating steps at different temperatures, simplifying the manufacturing process while achieving reliable bonds between dissimilar materials
2Reliability
If solder and gold are used together in feedthrough construction, then bonding properties are improved, but manufacturing time increases due to twice the heating steps
Solution Approach 1:
The patent combines multiple bonding operations into a single gold-based brazing process. By using gold preforms that can bond to both the ferrule and the capacitor lead simultaneously in one heating cycle, the invention eliminates the time required for separate soldering and gold bonding steps, reducing total manufacturing time while maintaining reliable electrical and mechanical connections
3Ease of manufacture
If silver-palladium coating is used on capacitors, then bonding with solder is promoted, but reliability decreases at temperatures below gold melting point
Solution Approach 1:
The patent replaces the silver-palladium coating (which deteriorates at brazing temperatures) with a gold preform that is specifically designed for high-temperature brazing. The gold preform acts as a temporary bonding medium that is consumed during the brazing process, forming permanent, thermally stable gold bonds that can withstand the high temperatures of the brazing cycle without deteriorating
Solution Approach 2:
The patent uses composite gold preforms with controlled composition and microstructure to achieve both ease of bonding and thermal stability. The preform material is formulated to be soft and formable at brazing temperatures for easy bonding, yet maintains structural integrity and reliability at service temperatures, combining properties that would be difficult to achieve with a single material
4Reliability
If multiple heating steps are used for gold and solder, then bonding reliability is improved, but productivity decreases
Solution Approach 1:
The patent merges multiple heating steps into a single brazing operation. By using gold preforms that can simultaneously bond all components (ferrule, capacitor, insulator) in one heating cycle, the invention eliminates the need for sequential heating steps, thereby improving manufacturing efficiency and productivity while maintaining reliable bonds through controlled preform composition and geometry
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 simplifies the manufacturing process, reduces complexity and cost, and ensures reliable fluid isolation and electrical connectivity with reduced risk of surface arcing in high-voltage environments.
Implementation Method 1
a single brazing step may be utilized to secure components in the feedthrough with respect to one another
Implementation Method 2
applying heat to bond the components together
Data Source
AI summary
Implantable medical device having a feedthrough, a feedthrough and method for making such feedthrough. The feedthrough has a ferrule, an electrically conductive pin, a preform having a preform liquidus temperature, a capacitor, positioned within the ferrule abutting the preform, having a coating having a coating liquidus temperature and being configured to electrically couple with the preform, and an insulative assembly configured, at least in part, to seal against passage of a liquid through the ferrule, and having an insulative assembly liquidus temperature. The coating liquidus temperature is greater than the preform liquidus temperature and the coating liquidus temperature being greater than the insulative assembly liquidus temperature.