Friction Stir Welding Pin With Annular Friction Surface for Stability
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Solution Overview
Problem
Friction pins in friction stir welding systems are prone to breakage due to local material variations, such as hardness changes in cast materials, leading to operational inefficiencies and reduced tool service life.
Innovation Solution
A device and method that incorporate a tool drive with a conical tool dome, a tool shoe with a smoothing and compacting surface, and an annular friction surface surrounding a conveying screw, which heats the materials to increase welding speed and stability, while a lifting device with rolling rollers addresses burrs and unevennesses, optimizing the breakaway edge and reducing internal friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the welding pin operates through local material variations with high contact pressure, then material transport is achieved, but pin breakage occurs due to hardness variations and reduced service life
Solution Approach 1:
The patent changes the geometric parameters of the pin tip by introducing an annular friction surface at a specific distance from the pin tip, and modifies the conveying screw thread direction to counter the pin tip thread. These parameter changes optimize material transport while reducing stress concentrations that lead to pin breakage, thereby improving both welding speed and pin reliability simultaneously.
2Productivity
If the contact pressure between tool and material is increased to improve material transport, then welding speed increases, but self-heating of the tool increases and service life decreases
Solution Approach 1:
The patent segments the tool structure by introducing a distinct annular friction surface separated from the pin tip by a specific distance. This segmentation allows the friction heating to occur at the annular surface rather than directly at the pin tip, reducing self-heating of the tool while maintaining effective material transport, thus increasing welding speed without excessive temperature rise.
3Ease of manufacture
If the pin tip geometry is simplified for ease of manufacture, then manufacturing cost decreases, but material transport efficiency and welding performance are reduced
Solution Approach 1:
The annular friction surface serves multiple functions: it generates friction heat for material softening, provides a seating surface for the conveying screw, and creates a geometric feature that enhances material transport efficiency. This multi-functional design improves material transport without requiring complex additional components, maintaining ease of manufacture while enhancing welding performance.
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 solution enhances welding speed and tool service life by minimizing contact pressure, reducing self-heating, and effectively managing material transport, thereby preventing pin breakage and ensuring consistent welding performance.
Implementation Method 1
the annular friction surface (9) heats the parts (5) to be joined by friction and thus increases the speed of the welding operation
Implementation Method 2
a conveying screw (8) for the output of the material transport from the pin tip (10), the thread of which conveying screw runs counter to the thread of the pin tip (10)
Implementation Method 3
a lifting device (18) for the possible swiveling of a rolling-roller arm (17) into the region of the abutment edge (19) of the parts (5) to be joined, and in that the half radius (15) of the smoothing and compacting surface (11) adjoins the pin shank (6)
Data Source
AI summary
The invention relates to a device and method for increasing the speed and increasing the stability of the welding pin in friction stir welding with the following device features: a) a tool drive (1) has a retaining flange (2) for a cone-shaped tool cover (3) with a union nut (4); b) an annular retaining ring (12) surrounds a pin shank (6) with a tool shoe (7) secured to the diameter of the retaining ring (12), wherein the tool shoe (7) has a smoothing and compressing surface (11) in the region of the pin tip (10) for smoothing the weld seam, wherein the pin shank has the width of the tool shoe (7); c) the pin tip (10) has an annular friction surface (9) which surrounds a screw conveyor (8) for the output of material transport from the pin tip (10), which has a thread running in the opposite direction to the thread of the pin tip (10).