Liquid Cooling Jacket Friction Stir Joining With Reduced Groove Defects
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Solution Overview
Problem
Conventional methods for manufacturing liquid cooling jackets result in larger recessed grooves and coarser joined surfaces due to the flow of plastically fluidized material into tapered surfaces, leading to reduced joining quality and increased burr formation.
Innovation Solution
A method involving a primary joining rotary tool with a base end pin and distal end pin of different taper angles, where the base end pin has a stepped portion and the distal end pin has a flat surface with a protrusion, is used to perform friction stirring in a manner that reduces the size of the recessed groove and prevents material adherence, thereby stabilizing the joined surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction stir joining is performed with a conventional rotary tool having a shoulder portion and stirring pin, then joining can be performed, but plastically fluidized material flows into the groove formed in the tapered surface, causing the groove to malfunction and deteriorating joining quality
Solution Approach 1:
The invention removes the problematic groove structure from the rotary tool design. Instead of having a groove in the stirring pin that gets filled with plastically fluidized material, the patent uses a simple cylindrical stirring pin without any grooves, channels, or hollow structures that could trap material. This extraction of the problematic feature eliminates the malfunction while preserving the joining function.
Solution Approach 2:
Conventional designs use grooves to control material flow, but this backfires when material fills the groove. The invention inverts the approach by using a solid, grooveless stirring pin that prevents material accumulation through its simple geometry, allowing material to flow smoothly around it without being trapped.
2Ease of manufacture
If friction stir joining is performed with a rotary tool having a stirring pin with a spiral groove, then joining can be performed, but the joined metal members are rubbed with adhered material causing deterioration of joining quality
Solution Approach 1:
The invention extracts and removes the spiral groove feature from the stirring pin design. By using a smooth, grooveless cylindrical pin, the patent eliminates the surface where material adheres and subsequently rubs against the joined pieces, thereby preventing quality deterioration while maintaining the friction stir joining processability.
3Productivity
If friction stir joining is performed with a rotary tool having a stirring pin with a spiral groove, then joining can be performed, but recessed grooves are formed larger and joined surfaces are made coarser
Solution Approach 1:
The invention removes the spiral groove structure that causes material accumulation and surface roughening. The smooth cylindrical stirring pin allows plastically fluidized material to flow uniformly without being trapped and extruded as coarse surface features, thereby maintaining joining efficiency while significantly improving surface finish quality.
Solution Approach 2:
The invention changes the geometric parameters of the stirring pin from a grooved structure to a smooth cylindrical form. This parameter change in the tool geometry fundamentally alters material flow patterns, preventing the formation of large recessed grooves and coarse surfaces while preserving productive joining operation.
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 reduces the size of recessed grooves, minimizes burr formation, and enhances the joining quality by controlling the flow of plastically fluidized material and increasing the joining strength of the liquid cooling jacket components.
Implementation Method 1
performing friction stirring to a first overlapped portion, where the peripheral wall end surface of the peripheral wall portion is overlapped with a rear surface of the sealing body
Implementation Method 2
plastically fluidized material flows into the groove
Implementation Method 3
the plastically fluidized material flows into the groove formed in the tapered surface
Data Source
AI summary
Provided is a method for manufacturing a liquid cooling jacket including a jacket body and a sealing body joined to the jacket body. The method includes steps of: preparing; placing; first primary joining with a rotary tool; and second primary joining with the rotary tool. A rotary tool includes a base end pin and a distal end pin. The distal end pin includes a flat surface and a protrusion extending from the flat surface. In the first primary joining and the second primary joining, friction stirring is performed in a state where a front surface of the sealing body is brought in contact with an outer peripheral surface of the base end pin, the sealing body is brought in contact with the flat surface of the distal end pin, and the jacket body is brought in contact with the protrusion.