Friction Stir Spot Welding Tool Dynamic Control
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Solution Overview
Problem
In friction stir spot welding, serial spot welding processes often result in impaired external appearances of objects due to heat accumulation in the welding tool, causing material softening and uneven deposition during multiple welds.
Innovation Solution
A friction stir spot welding device and method that include a pin member and a shoulder member, both rotatable and retractable, with a position detector and controller to manage the axial positions and forces applied during welding, ensuring the tip end surfaces of the pin and shoulder members remain coplanar and adjust forces and speeds based on detected positions to maintain a consistent welding quality across multiple welds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If serial spot welding is performed using friction stir welding, then productivity is improved through continuous welding operations, but heat accumulates in the welding tool causing material softening and degradation of external appearance
Solution Approach 1:
The patent implements dynamic control of the welding tool's axial position and pressing force during serial welding operations. The controller adjusts the axial position of the pin member and shoulder member based on detected positions, and dynamically modifies pressing force parameters between welds to prevent heat accumulation while maintaining continuous productivity.
Solution Approach 2:
The patent changes welding parameters (axial position, pressing force, rotational speed) between serial welding operations. The controller modifies these parameters based on detected tool positions and heat accumulation patterns, allowing continuous welding while preventing material softening and external appearance degradation.
2Manufacturing precision
If high pressing force and rotational speed are maintained during serial welding, then welding quality is improved, but heat accumulation causes material to soften and move outward deforming the external appearance
Solution Approach 1:
The patent uses a detection device to monitor the axial position of the welding tool during serial welding operations. The controller receives this feedback and adjusts pressing force and axial position parameters to maintain welding quality while preventing excessive heat accumulation that would cause material deformation and poor external appearance.
Solution Approach 2:
The system dynamically adjusts pressing force and axial position between welds based on real-time detection data. This dynamic control maintains consistent welding quality across serial operations while preventing heat-induced material softening and external appearance degradation.
3Productivity
If the welding tool operates continuously without parameter adjustment, then productivity is maintained, but heat accumulation causes the pin and shoulder member tip surfaces to become non-coplanar deforming the weld
Solution Approach 1:
The detection device monitors the axial positions of the pin member and shoulder member tip surfaces during continuous welding. The controller uses this feedback to adjust axial positions and pressing forces, maintaining coplanarity of the tip surfaces throughout serial welding operations while preserving productivity.
Solution Approach 2:
The system implements dynamic adjustment of axial positions for the pin and shoulder members during continuous welding operations. Based on detected positions and heat accumulation patterns, the controller modifies these parameters to maintain tip surface coplanarity while sustaining continuous welding productivity.
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 ensures a good welding quality by preventing material softening and deposition issues, maintaining a consistent external appearance during serial spot welding by adjusting forces and speeds dynamically based on detected positions.
Implementation Method 1
a friction stir spot welding device, which welds an object to be welded, by softening the object by friction heat and by stirring the object
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A friction stir spot welding device of the present invention comprises a pin member (11), a shoulder member (12), a rotation driving unit (57), a tool driving unit (53), a position detector (21), and a controller (51), wherein the controller (51) sets as a reference position the position of the tip end surface of the pin member (11) or the shoulder member (12) at a time point when the tip end surface of the pin member or the shoulder member contacts an obverse surface (60c) of an object (60), and controls the tool driving unit (53) to reduce a pressing force applied to the object by the pin member (11) and a pressing force applied to the object by the shoulder member (12) in a next welding process, and/ or controls the rotation driving unit (57) to reduce a rotational speed of the pin member (11) and a rotational speed of the shoulder member (12) in the next welding process, in a case where a first position which is the position of the tip end surface of the pin member (11) or the shoulder member (12) is within a first region.