Braze Joining Thermal Shrink Fit Workpiece Alignment
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Solution Overview
Problem
Conventional brazing processes require tight tolerances in joint clearance to achieve a satisfactory braze joint, which increases manufacturing costs and complexity due to the need for precise concentricity of workpieces.
Innovation Solution
The method involves forming an interior or exterior annular thermal shrink seating region with a specific cross-sectional perimeter, allowing for a thermal shrink fit that enables the metal filler to flow into a braze region without requiring tight tolerances, using heat sources like magnetic flux fields to melt and flow the filler metal into the joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tight tolerances are maintained in joint clearance to achieve satisfactory braze joint, then joint integrity is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent applies preliminary action by performing thermal shrink fitting of the first workpiece to the second workpiece before applying filler metal. The first workpiece is heated to expand it, allowing easy insertion, then cooled to create a tight interference fit that establishes proper joint clearance. This preliminary mechanical alignment eliminates the need for tight tolerance control during subsequent brazing operations, resolving the contradiction between joint integrity and manufacturing complexity
Solution Approach 2:
The patent utilizes parameter changes by exploiting thermal expansion and contraction of the first workpiece. The workpiece is heated to raise its temperature and expand its dimensions, enabling straightforward assembly with the second workpiece. Upon cooling, the workpiece contracts to create the desired interference fit and joint clearance. This dynamic parameter change allows tolerance compensation without affecting final joint quality
2Manufacturing precision
If tight tolerances are maintained in concentricity of workpieces, then filler metal flow is controlled, but manufacturing cost increases
Solution Approach 1:
The patent applies parameter changes by heating the first workpiece to expand it radially, allowing insertion of the second workpiece without precise concentricity alignment. As the workpiece cools, it contracts to establish proper radial clearance around the second workpiece. This thermal parameter change compensates for concentricity variations, eliminating the need for expensive tight tolerance manufacturing equipment and processes
3Device complexity
If thermal shrink fit is applied to allow loose tolerances, then manufacturing complexity is reduced, but joint clearance control becomes challenging
Solution Approach 1:
The patent performs the thermal shrink fit as a preliminary action before applying filler metal. The first workpiece is heated and expanded, the second workpiece is inserted with minimal alignment requirements, then the first workpiece is allowed to cool and contract, automatically establishing uniform joint clearance. This preliminary mechanical assembly with tolerance compensation simplifies manufacturing while ensuring proper clearance control for subsequent 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
This approach allows for a satisfactory braze joint to be formed without the need for precise concentricity, reducing manufacturing costs and complexity while maintaining joint integrity.
Implementation Method 1
The interior wall of an end of the second article is seated around the thermal shrink region by a thermal shrink process
Implementation Method 2
bring the articles around the filler region into the presence of a magnetic flux field to inductively heat at least one of the articles and melt the metal filler
Implementation Method 3
bring the articles around the filler region into the presence of a magnetic flux field to inductively heat at least one of the articles
Implementation Method 4
melt the metal filler so that it flows at least into the braze region to establish the braze joint
Data Source
AI summary
A braze joint is made between two workpieces by first forming a thermal shrink fit region between the two workpieces adjacent to, or around, a braze or filler region in which a filler metal is located adjacent to, or within. The filler metal is suitably heated so that it flows in the braze or filler region to form the braze joint of the two workpieces. Cutouts may be formed in the thermal shrink fit region adjacent to the braze or filler region to extend the braze joint region or provide paths for gas byproducts in the brazing process.