Luminescent Braze Preform Coating for Assembly Detection
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Solution Overview
Problem
Automating brazing procedures is challenging due to the difficulty in confirming whether braze preforms are assembled onto components before heating, as existing methods require sophisticated and expensive sensors or are incompatible with brazing processes, potentially leading to contamination and joint failures.
Innovation Solution
A braze preform with a luminescent material covering at least a portion of the filler metal, which is applied as a thin coating and evaporates below the melting temperature, allowing for detection using a light source and sensor to verify assembly without contaminating the braze joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If sophisticated optical or mass sensors are used to detect braze preforms, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies luminescent material to the braze preform that changes its optical properties under UV illumination. The luminescent material absorbs UV light and emits visible light, creating a detectable signal that indicates preform presence. This simple optical change enables detection without complex sensors.
Solution Approach 2:
The luminescent material acts as an intermediary between the UV light source and the detection system. It converts UV illumination into visible luminescence that can be easily detected by simple optical sensors or even visual inspection, bridging the gap between the preform and detection capability.
2Difficulty of detecting and measuring
If inks are applied to make braze preforms visually conspicuous, then detection capability is improved, but contamination of flux or filler metal occurs
Solution Approach 1:
The patent changes the concentration parameter of luminescent material to extremely low levels (0.01-0.15% by weight). At these diluted concentrations, the material provides sufficient luminescence for detection while being inert enough not to contaminate the flux or filler metal during brazing.
Solution Approach 2:
The luminescent material is applied as a thin coating only on the surface of the braze preform, concentrating the detection function at the interface where it is needed, while the bulk filler metal remains pure and uncontaminated.
3Difficulty of detecting and measuring
If luminescent material is applied as a coating, then detection capability is improved, but the coating may contaminate the brazing process
Solution Approach 1:
The patent optimizes the weight percentage of luminescent material in the coating to a specific range (0.01-0.15% of total preform weight). This parameter control ensures the coating is thin enough to burn off completely or vaporize without contaminating the brazing process, while still providing detectable luminescence.
Solution Approach 2:
The luminescent coating is designed as a temporary, consumable element that serves its detection purpose and then is completely consumed during the brazing process through burning off or vaporization, leaving no harmful residue.
4Productivity
If automated detection systems are implemented, then productivity is improved, but device complexity and cost increase
Solution Approach 1:
The luminescent material provides a simple binary optical signal (luminesces or does not luminesce) that can be detected by basic optical sensors integrated into automated systems. This simple signal type enables automation without requiring complex analysis or processing systems.
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
Enables automated detection of braze preform presence, reducing the risk of contamination and ensuring strong, reliable brazed joints by using a highly diluted luminescent material that does not introduce imperfections into the braze pool, allowing for efficient and accurate assembly verification.
Implementation Method 1
a luminescent material that covers at least a portion of the filler metal
Implementation Method 2
The luminescent material is burned off at or below the melting temperature of the filler metal
Data Source
AI summary
A braze preform includes a filler metal, a flux in communication with the filler metal, and a luminescent material covering at least a portion of the filler metal. The luminescent material is equal to or less than 0.15% total weight of the braze ring. Further, the luminescent material includes at least one of a luminescent ink, a solvent, and a binder. The solvent may be one of a bromide-based solvent or a non-chlorine-based solvent. The binder may be an acrylic resin.