Friction Stir Welding Tool for Deep Heat Exchanger Grooves
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Solution Overview
Problem
Existing friction stir welding methods face challenges in performing welds at deep positions due to increased load and friction, especially when dealing with thick metal members or large channel depths in heat exchanger plates, making it difficult to achieve air-tightness and water-tightness.
Innovation Solution
A method involving a rotary tool with a tapered stirring pin and a preliminary joining process to reduce friction by only the pin contacting the metal members, followed by a primary joining process that minimizes tool contact, allowing for reduced load application and efficient welding at deep positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the outer diameter of the shoulder is increased to accommodate larger stirring pin for deep position welding, then the stirring pin can reach deeper positions, but the friction between the shoulder and the base member and lid plate becomes larger, resulting in larger load on the friction stir device
Solution Approach 1:
The invention extracts the shoulder from the friction stir welding tool, using only the stirring pin for welding. This eliminates the friction between the shoulder and the workpiece that occurs in conventional friction stir welding, thereby reducing the load on the friction stir device while enabling deep position welding.
Solution Approach 2:
The invention introduces a preliminary joining process as an intermediary step before the primary friction stir welding. This preliminary process creates initial mechanical interlocking and thermal softening, which reduces the friction and load during the subsequent primary welding process at deep positions.
2Reliability
If conventional friction stir welding is performed with both shoulder and stirring pin contacting the workpiece, then stable welding can be achieved, but the friction and load become excessively large for deep position welding
Solution Approach 1:
The welding process is segmented into two distinct stages: a preliminary joining process that creates initial bonding, and a primary friction stir welding process that completes the joint. This segmentation allows each stage to be optimized independently, with the preliminary process reducing friction for the main welding operation.
Solution Approach 2:
The shoulder is removed from the friction stir welding tool, leaving only the stirring pin to contact the workpiece. This extraction eliminates the excessive friction and load that prevent deep position welding, while the two-stage process maintains welding stability.
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 easier friction stir welding at deep positions, improving air-tightness and water-tightness of heat exchanger plates by reducing the load on the friction stir device and preventing aperture formation during the welding process.
Implementation Method 1
a primary joining process to insert the stirring pin, which is rotating, from a front surface of the other metal member, and to perform friction stirring to the overlapped portion
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The object is to provide a method for manufacturing a heat exchanger plate capable of easily performing friction stir welding at a deep position of the heat exchanger plate, and capable of improving air-tightness and water-tightness. The method includes a lid groove closing process to insert a lid plate (5) into a lid groove (4) formed at a periphery of a concave groove (3) opening to a surface (2a) of a base member (2) ; and a primary joining process to perform friction stirring while relatively moving a primary joining rotary tool equipped with a stirring pin (F2) along a butting portion (J) of a side wall of the lid groove (4) and a side surface of the lid plate (5), and in the primary joining process, the rotating stirring pin (F2) is inserted into the butting portion (J), and the friction stirring is performed in a state of only the stirring pin (F2) being in contact with the base member (2) and the lid plate (5).