Liquid-Cooling Jacket Friction Stir Joining With Reduced Groove Roughness
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Solution Overview
Problem
Conventional methods for manufacturing liquid-cooling jackets using friction stir welding result in large recessed grooves and surface roughness due to the adherence of plastically fluidized material, leading to reduced joining quality and increased burr formation.
Innovation Solution
A method involving a rotary tool with a base side pin and a tip side pin, where the base side pin has a larger tapered angle and a stair-like step part on its outer surface, allowing for controlled plastic fluidization and reduced adherence, and additional friction stir welding to a second overlapped part for enhanced joining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a rotary tool with a shoulder part is used to push into the metal member during friction stir welding, then plastically fluidized material can be held to reduce burr generation, but a large recessed groove is generated and surface roughness increases
Solution Approach 1:
The rotary tool is divided into two separate pins: a base pin that contacts the first metal member and a tip pin that contacts the second metal member. This segmentation allows each pin to perform its specific function independently - the base pin holds plastically fluidized material to reduce burrs, while the tip pin controls the welding process without creating large recessed grooves or excessive surface roughness.
2Adaptability or versatility
If plastically fluidized material enters the groove on the tapered surface, then joining can be stably performed even when thickness or height position changes, but the groove does not work and friction stirring quality lowers due to adhered material
Solution Approach 1:
The single tapered pin is segmented into a base pin with a first tapered surface contacting the first metal member and a tip pin with a second tapered surface contacting the second metal member. This prevents plastically fluidized material from entering between the pins, allowing the grooves to function properly while maintaining joining stability across different thickness variations.
Solution Approach 2:
The base pin acts as an intermediary that contacts the first metal member and controls the plasticization process, preventing material from flowing into the gap between pins. This intermediary structure maintains stable joining across thickness variations while preventing the quality degradation caused by material adherence in grooves.
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 method effectively minimizes recessed groove size and surface roughness, stabilizes joining quality, and enhances the strength and deformation resistance of the liquid-cooling jacket while improving production efficiency.
Implementation Method 1
friction stir welding is performed by rotating a rotary tool provided with a base side pin and a tip side pin, and moving the rotary tool once around the recessed part along a first overlapped part where a back surface of the sealing body (3) and an end surface of the peripheral wall part (11) are overlapped each other
Implementation Method 2
a base side pin and a tip side pin, wherein a tapered angle of the base side pin is larger than another tapered angle of the tip side pin, wherein a stair-like step part is formed on an outer peripheral surface of the base side pin
Data Source
AI summary
A method for manufacturing a liquid-cooling jacket (1) where heat transfer fluid flows in a hollow part (14) defined by a jacket body (2) and a sealing body (3) includes: an overlapping process in which the sealing body (3) is placed on an end surface (11a) of a peripheral wall part (11) in such a way that the end surface (11a) and a back surface of the sealing body (3) are overlapped each other to form a first overlapped part (H1); and a primary joining process in which primary joining is performed by friction stirring in such a way that a rotary tool (F1) is moved once around a recessed part (13) along the first overlapped part (H1). In the primary joining process, the first overlapped part (H1) is joined in a state where the tip side pin is in contact with only the sealing body (3) or with the jacket body (2) and the sealing body (3) while the base side pin is in contact with the sealing body (3).