Friction Stir Welding Head with Elastic Force Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Friction stir welding using machine tools poses risks to the spindle due to significant forces exerted during the process, and variations in part distance can compromise weld quality, as existing machining spindles are not designed to handle these forces and may deform or fail prematurely.
Innovation Solution
A friction stir welding head with an outer frame fixed to the machine, featuring a drive part mounted on a rotatable axis, a tool holder with a shaft, and elastic elements to absorb axial forces and vibrations, allowing force transfer to the machine frame while isolating the spindle, and incorporating a compliance system to maintain constant welding quality despite geometric defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If friction stir welding is performed using a machine tool spindle, then the welding process can be automated and controlled, but the spindle is damaged by the significant forces exerted during welding
Solution Approach 1:
The welding head is segmented into separate functional components: the spindle remains in the machine tool while the welding tool, holder, and force-absorbing structures form a separate assembly. This segmentation allows the spindle to provide rotation without bearing welding forces, resolving the contradiction between automation and spindle durability.
Solution Approach 2:
An intermediary welding head assembly is introduced between the spindle and the workpiece. This intermediary structure includes the tool holder, shaft, and elastic elements that absorb welding forces, protecting the spindle while enabling automated welding through the spindle's rotational drive.
2Manufacturing precision
If the welding tool exerts large forces on the parts to ensure constant penetration, then weld quality is maintained, but the spindle is subjected to damaging reaction forces
Solution Approach 1:
The force-bearing function is extracted from the spindle and transferred to the welding head assembly. The tool holder and shaft are designed to withstand and transmit welding forces to the workpiece, while the spindle only provides rotational motion, eliminating the harmful reaction forces on the spindle.
Solution Approach 2:
The mechanical parameters of the welding head are optimized: the tool holder and shaft are designed with appropriate stiffness and strength to maintain constant penetration depth, while the elastic elements provide compliance to absorb force variations, achieving precision without overloading the spindle.
3Adaptability or versatility
If the distance between parts and machine tool varies due to dimensional inaccuracies or positioning errors, then positioning flexibility is improved, but weld quality deteriorates
Solution Approach 1:
The welding head incorporates dynamic compliance through elastic elements that allow automatic adjustment of the tool position relative to the workpiece. This dynamic adaptation compensates for distance variations caused by positioning errors or dimensional inaccuracies, maintaining weld quality while preserving positioning flexibility.
Solution Approach 2:
The welding head performs self-alignment and self-adjustment through its compliant mechanism. The elastic elements automatically compensate for distance variations without requiring external control systems or programming, enabling the system to adapt to positioning variations while maintaining consistent weld quality.
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 protects the spindle from excessive forces and vibrations, ensures constant welding quality by adapting to variations in part distance, and maintains a stable forging force range, thereby extending spindle lifespan and improving weld quality without requiring additional machine tool programming.
Implementation Method 1
at least one elastic element (9) for transferring the axial forces being interposed between the slider (5) and the frame (2)
Implementation Method 2
at least one flexible member (8) for absorbing vibrations is interposed between the coupling part (6) and the shaft (3)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a friction stir welding head (1) comprising a part (7) for driving the tool holder (4) in rotation. The tool holder (4) is secured to a shaft (3) mounted so as to rotate about the axis in a slide (5), guided in translation along the axis of the frame (2). A coupling part (6) is guided in translation along the axis on the part (7). The parts (6, 7) have first and second members (61, 71), respectively, for coupling one to the other in terms of rotation, the coupling part (6) and the shaft (3) being coupled in terms of rotation about the axis in order to drive the shaft (3) in rotation from the coupling part (6). And a resilient element (9) for transferring axial forces is interposed between the slide (5) and the frame (2).