Liquid-Cooling Jacket Joining with Stepped Dual-Pin Friction Stir Tool
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Solution Overview
Problem
The existing methods for manufacturing liquid-cooling jackets using different aluminum alloys face challenges in achieving sufficient mixing and joining, resulting in lower strength and cavity defects due to material hardness differences and friction-stir-welding limitations.
Innovation Solution
A method involving a rotary tool with a base side pin and a tip side pin, where the base pin has a larger taper angle and a staircase-shaped pin step portion, and the tip pin has a smaller taper angle and a spiral groove, is used to perform friction-stirring, focusing on the sealing body member to prevent the harder jacket body material from mixing excessively and ensuring adequate metal flow to enhance the joined portion's strength and water-tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction-stir-welding is performed with a single stirring pin on members of different aluminum alloys, then the joining process can be completed, but the stirring pin receives higher material resistance from the harder jacket body member, resulting in insufficient mixing and cavity defects
Solution Approach 1:
The single stirring pin is divided into two separate pins: a base side pin that contacts the jacket body member and a tip side pin that contacts the sealing body member. This segmentation allows each pin to be optimized for its specific material, reducing material resistance and improving mixing effectiveness.
Solution Approach 2:
Different portions of the stirring mechanism are given different properties: the base side pin has a larger taper angle for penetrating the harder jacket body member, while the tip side pin has a smaller taper angle for the softer sealing body member. This local differentiation optimizes the stirring action for each material type.
2Stability of the object's composition
If the stirring pin contacts both jacket body member and sealing body member, then mixing occurs, but the harder jacket body material mixes excessively with the softer sealing body material, creating cavity defects
Solution Approach 1:
The stirring mechanism is segmented into two pins with a gap between them, allowing controlled contact with each material. The base side pin stirs the jacket body member while the tip side pin stirs the sealing body member, preventing excessive mixing of the two materials while still achieving sufficient stirring for strength.
Solution Approach 2:
The taper angles of the two pins are differently optimized: the base side pin has a larger taper angle to penetrate the harder jacket body member, while the tip side pin has a smaller taper angle for the softer sealing body member. This parameter differentiation controls the mixing degree for each material.
3Ease of manufacture
If conventional friction-stir-welding is used on different aluminum alloys, then the joining process is simple, but cavity defects occur and the strength of the joined portion is lower
Solution Approach 1:
The stirring mechanism is divided into two pins that can be inserted through the same opening, maintaining the simplicity of the manufacturing process while significantly improving the quality of the joined portion by preventing cavity defects through optimized material interaction.
4Device complexity
If a single stirring pin is used, then the device structure is simple, but it cannot adequately handle the different material hardnesses of the two aluminum alloys
Solution Approach 1:
The rotary tool structure is segmented into two pins that rotate together, which slightly increases structural complexity but dramatically improves the ability to handle different material hardnesses by optimizing each pin's geometry for its specific material contact.
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 improves the strength and water-tightness of the joined portion by primarily stirring the softer sealing body material, reducing the risk of cavity defects and maintaining the integrity of the harder jacket body material, while also preventing metal deficiency and surface roughness.
Implementation Method 1
friction-stirring being performed by inserting the tip side pin and the base side pin of the rotary tool that is rotating into the sealing body member
Implementation Method 2
joining a jacket body member and a sealing body member through friction-stirring
Data Source
AI summary
A method for manufacturing a liquid cooling jacket has a feature of using a primary joining rotary tool provided with a tip side pin and a base side pin having a taper angle larger than a taper angle of the tip side pin and comprising a first primary joining process in which inserting the tip side pin and the base side pin of the rotary tool that is rotating into the sealing body member and moving the rotary tool along the first abutted portion with an outer circumferential face of the base side pin being in contact with a front face of the sealing body member and with the outer circumferential face of the tip side pin being kept off a step side face of the peripheral wall step portion while having a second aluminum alloy of the sealing body member flow into the gap.