Friction Stir Spot Welding Tool Wear Detection via Annular Recess
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Solution Overview
Problem
Existing friction stir spot welding methods fail to provide a means to judge the abrasion state of the tool from the surface of the joined object, necessitating periodic tool removal for inspection.
Innovation Solution
The apparatus and method involve forming a joint structure with an annular recess on the joining part, allowing visual inspection of the surface to determine tool wear by observing the shape transferred onto the surface during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the tool is used for friction stir spot welding, then the joining quality is improved, but the abrasion state of the tool cannot be judged from the surface of the to-be-joined object
Solution Approach 1:
The invention creates a copy or imprint of the tool's tip-end part shape on the surface of the to-be-joined object. By forming an annular recess with a bottom surface that reflects the tool's shape characteristics, the surface serves as a visual record of the tool's condition. This allows operators to inspect the surface and infer tool abrasion state without removing the tool, resolving the contradiction between maintaining good joining quality and enabling easy tool condition detection.
2Difficulty of detecting and measuring
If the tool is periodically removed for inspection, then the tool abrasion state can be judged, but the productivity is reduced due to interruption of welding operation
Solution Approach 1:
The welding process itself creates the inspection feature on the workpiece surface. The annular recess formed during friction stir spot welding inherently contains shape information about the tool's tip-end part. This self-service mechanism allows the workpiece to simultaneously serve as both the welded component and the inspection medium, eliminating the need to stop welding operations for tool inspection and thereby maintaining high productivity while enabling easy tool condition assessment.
3Reliability
If the tip-end part of the shoulder member is worn, then the joining quality deteriorates, but there is no visible indication on the surface of the to-be-joined object
Solution Approach 1:
The invention creates a copy or imprint of the tool's tip-end part shape on the surface of the to-be-joined object. By forming an annular recess with a bottom surface that reflects the tool's shape characteristics, the surface serves as a visual record of the tool's condition. This allows operators to inspect the surface and infer tool abrasion state, preventing information loss about tool wear that would otherwise go undetected until joining quality deteriorates.
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
Enables non-invasive, real-time assessment of tool wear by inspecting the surface of the joined object, facilitating continuous operation without manual tool inspection.
Implementation Method 1
joining a to-be-joined object by softening the object with frictional heat
Data Source
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AI summary
A friction stir spot welding apparatus according to the present disclosure includes a pin member (11) formed in a solid cylindrical shape, a shoulder member (12) formed in a hollow cylindrical shape, the pin member (11) being inserted in the shoulder member (12), a rotary actuator (57) that rotates the pin member (11) and the shoulder member (12) on an axis (Xr) that is in agreement with an axial center of the pin member (11), and a linear actuator (53) that linearly moves each of the pin member (11) and the shoulder member (12) along the axis. A tip-end part (120) of the shoulder member (12) is formed in a tapered shape.