Flexible Flux-Coated Brazing Material for Continuous Length Applications
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Solution Overview
Problem
Current flux-coated and flux-cored brazing materials are brittle, limiting their ability to be bent, curled, or deformed, and are restricted to shorter lengths due to post-cure baking requirements, which increases manufacturing costs and reduces their versatility in forming complex shapes or continuous lengths.
Innovation Solution
A flux composition comprising a solvent, binder, and plasticizer, with a non-hygroscopic flux content between 30-50% by weight, a binder between 10-30% by weight, and a plasticizer between 1-20% by weight, applied as a coating or core that is flexible and durable, allowing for continuous length brazing materials that can be coiled, spooled, or formed into various shapes without requiring post-cure heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional flux-coated brazing materials are used, then the flux provides adequate oxide removal, but the material becomes brittle and cannot be bent or deformed
Solution Approach 1:
The patent changes the physical and chemical parameters of the flux composition by incorporating specific plasticizers (e.g., dibutyl phthalate, dioctyl phthalate) and binders (e.g., polyvinyl chloride, polyacrylonitrile) in controlled ratios. These parameter changes transform the flux from a brittle state to a flexible state that can be bent and deformed without cracking, while maintaining its oxide removal capability during brazing.
Solution Approach 2:
The patent creates a composite flux material combining traditional fluxing agents (borates, fluorides, chlorides) with polymers and plasticizers. This composite structure integrates the oxide removal function of traditional fluxes with the flexibility properties of polymer-plasticizer combinations, resulting in a material that exhibits both chemical reactivity and mechanical flexibility.
2Ease of manufacture
If post-cure baking is required to harden the flux coating, then the flux becomes durable, but manufacturing costs increase and continuous lengths are limited
Solution Approach 1:
The flux coating is formulated to self-harden through ambient conditions or controlled drying without requiring post-cure baking. The plasticizer-polymer system is designed to achieve adequate hardness and durability through evaporation of solvents and self-organization of polymer chains, eliminating the need for energy-intensive baking processes and enabling continuous length production.
Solution Approach 2:
The patent uses cost-effective plasticizers and binders that provide sufficient durability without requiring expensive post-cure processing. The formulation achieves adequate flux durability through careful selection of affordable polymer-plasticizer combinations, reducing manufacturing costs while maintaining functional performance.
3Adaptability or versatility
If the flux coating is made flexible to allow bending, then complex shapes can be formed, but the flux may crack or detach
Solution Approach 1:
The patent optimizes the plasticizer-to-polymer ratio and selects specific plasticizer types (e.g., phthalates, citrates) that provide flexibility without compromising coating integrity. By controlling the molecular weight, concentration, and chemical structure of the plasticizer, the flux achieves a balance between flexibility for shape formation and stability to prevent cracking or detachment during handling and brazing.
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 provides a flexible and durable flux coating that prevents cracking and detachment, enabling continuous length brazing materials to be effectively used in complex geometries and reducing manufacturing costs by eliminating the need for post-cure baking, while ensuring a strong and clean brazing joint.
Implementation Method 1
the flux must be capable of removing metal oxides at pre-selected brazing temperatures
Implementation Method 2
the brazing material melts, wetting the surfaces of the components being joined, and is drawn or held in the joint gap by capillary action
Implementation Method 3
A flux composition comprising a solvent, binder, and plasticizer... allowing for continuous length brazing materials that can be coiled, spooled, or formed into various shapes
Data Source
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Figure 3
Figure 4A~4F
AI summary
A flux coated brazing material wherein the flux coating composition is suitable for continuously coating a continuous length of brazing material. Aspects include a flux coating composition for coating or coring a brazing material useful as a flux coating for preparing a continuous length brazing material according to the described method.