Friction Stir Welding Head Control for Constant Weld Depth
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Solution Overview
Problem
Conventional friction stir welding methods face issues in maintaining the depth-direction position of the welding tool leading end part consistently, leading to variations in the welded part's depth, which affects welding quality, especially when welding composite materials with different thicknesses.
Innovation Solution
A friction stir welding apparatus and method that control the Z-direction position of the welding tool holder unit by integrating a control unit to adjust the height and swing mechanism, allowing for precise alignment and maintaining a constant depth of the welded part throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the welding tool is swung with a swing axis as fulcrum while fixing the hold position of the welding head, then the welding tool can cover a wider welding area, but the leading end part of the welding tool draws an arc causing position variation and reducing welding quality
Solution Approach 1:
The patent applies dynamics by making the hold position of the welding head movable in the depth direction during the swinging motion. Instead of fixing the hold position, the system dynamically adjusts it to compensate for the arc drawn by the welding tool leading end, thereby maintaining position accuracy while preserving the swinging motion's ability to cover wider welding areas
Solution Approach 2:
The patent implements feedback control by continuously monitoring the position of the welding tool leading end and adjusting the hold position of the welding head in real-time. The control unit calculates the required hold position based on swinging parameters and feedback information, ensuring the leading end maintains accurate position throughout the welding process
2Device complexity
If the hold position of the welding head is fixed during swinging, then the control system is simpler, but the depth-direction position of the welding tool leading end varies from start to end of welding
Solution Approach 1:
The patent applies preliminary action by pre-calculating and setting the hold position of the welding head before the swinging motion begins. The control unit determines the appropriate hold position based on the swinging parameters and welding requirements, preparing the system in advance to maintain consistent welding depth throughout the process
Solution Approach 2:
The system transitions from a static fixed hold position to a dynamic adjustable hold position that changes during the welding process. This dynamic adjustment is controlled by the control unit which modifies the hold position in the depth direction to compensate for swinging-induced position variations, maintaining welding quality consistency
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
Ensures high welding reliability and quality by maintaining a consistent depth of the welded interface, particularly in composite materials like steel and aluminum, and allows for complex shapes with curved surfaces to be welded accurately.
Implementation Method 1
Friction stir welding (FSW) which welds together welded materials by softening the welded materials with friction heat which is generated by rotating a columnar welding tool and stirring that part
Data Source
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AI summary
Provided are a friction stir welding apparatus and a friction stir welding method which make it possible to maintain a depth of a welded part constant without varying a depth-direction (Z-direction) position of a welding tool leading end part relative to welded members from start of friction stir welding to end of friction stir welding. The friction stir welding apparatus which welds together welded members by friction stir welding includes an apparatus main body, a control device which controls an operation of the friction stir welding apparatus, a swing mechanism unit which is connected to the apparatus main body via an up/down motion drive mechanism section, a holder unit which is connected to the swing mechanism unit via a revolving mechanism section, and a welding tool which is held to the holder unit, in which the control device has a first welding mode in which friction stir welding is performed on the basis of a welding condition signal for deciding a welding condition of the welding tool, a swing control signal for controlling the swing mechanism unit, and a first hold position decision signal for deciding a hold position of the welding tool by the up/down motion drive mechanism section, and a second welding mode in which friction stir welding is performed on the basis of the welding condition signal, the swing control signal, and a second hold position decision signal which is obtained by correcting the first hold position decision signal so as to control a depth of a welded part constant in accordance with a state of the welded members, and includes the first welding mode and the second welding mode in one welding pass from insertion of the welding tool into between the welded members to draw-out thereof.