Friction Stir Welding Tool with Movable Counterholder
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Solution Overview
Problem
Friction stir welding faces challenges with wear of counterholders, complex control systems, and reduced weld quality due to varying component thicknesses and thermal expansion in spherically shaped components, especially in aircraft fuselage shell elements, where the distance between the stirring pin and counter-holder is critical and prone to fluctuations.
Innovation Solution
A method and device where the stirring pin dips into a carriage that supports the components and moves along the joining zone, allowing for automatic adjustment of immersion depth and eliminating the need for precise depth setting, using a tool with a rotating shoulder surface and a rotatable stirring pin that penetrates the carriage, ensuring consistent support and heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stationary counterholder is used to support components during friction stir welding, then the components are supported in the joining zone, but the counterholder is subject to high wear and must be replaced sporadically
Solution Approach 1:
The patent applies the dynamics principle by making the counterholder movable instead of stationary. The counterholder is designed to move in the welding direction, allowing it to automatically adjust its position and maintain optimal contact with the component surface throughout the welding process, thereby reducing wear and eliminating the need for frequent replacements while maintaining stable support.
Solution Approach 2:
The movable counterholder system enables self-adjustment during welding. As the welding progresses and the component moves relative to the tool, the counterholder automatically follows the component's contour and position changes, providing continuous adaptive support without requiring external intervention or manual adjustment, thus reducing maintenance requirements.
2Manufacturing precision
If the distance between the stirring pin and counterholder is precisely controlled, then sufficient stirring of plasticized material is enabled, but the system becomes sensitive to thickness fluctuations and gap width variations
Solution Approach 1:
The patent resolves this contradiction by making the counterholder movable, which dynamically adjusts the distance between the stirring pin and counterholder during welding. This dynamic adjustment automatically compensates for thickness fluctuations and gap width variations, maintaining optimal stirring depth without requiring complex control systems or sacrificing adaptability to dimensional variations.
Solution Approach 2:
The movable counterholder acts as a passive feedback mechanism. As the component thickness or gap width changes, the counterholder position automatically adjusts in response, maintaining the correct stirring depth. This mechanical feedback system eliminates the need for active sensing and control systems while ensuring consistent stirring quality.
3Manufacturing precision
If a sensing device and actuator are used to control stirring pin immersion depth, then thickness fluctuations are compensated, but the control system becomes complex in terms of device and control technology
Solution Approach 1:
The patent eliminates complex sensing and control systems by using a movable counterholder that passively self-adjusts to maintain optimal stirring depth. The system uses the welding process itself to drive the counterholder movement, requiring no external sensors, actuators, or control electronics, thus dramatically simplifying the overall system while maintaining precision.
Solution Approach 2:
The movable counterholder serves as a mechanical intermediary that translates component position and thickness variations into automatic adjustments of the stirring pin immersion depth. This mechanical mediation replaces complex electronic control systems with a simple, reliable mechanical linkage that automatically compensates for variations.
4Ease of operation
If the stirring pin is pressed with constant force against components, then the process is simplified, but the immersion depth changes with component thickness variations
Solution Approach 1:
The patent combines constant force application with dynamic counterholder movement. The stirring pin is pressed with constant force, simplifying process control, while the movable counterholder simultaneously adjusts its position to compensate for thickness variations, maintaining consistent immersion depth. This dynamic adaptation allows simple force control to achieve precise stirring results.
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 solution enables high-quality weld seams by automatically compensating for component thickness variations and reducing wear on the counter-holder, simplifying control and maintaining consistent heat input, thus improving the robustness and reliability of the welding process.
Implementation Method 1
The friction between the shoulder surface and the components generates heat, which plasticizes the material in the butt joint
Implementation Method 2
a rotating stirring pin for stirring plasticized material or for plasticizing and stirring the components in the area of the joining zone
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a method for friction stir welding two components, comprising a rotating tool, which has a rotating or not rotating shoulder surface for applying a process force to the components in the region of a joining zone and a stirring pin for stirring plasticized material or for plasticizing and stirring the components in the region of the joining zone, wherein a section of a stirring pin slidably enters a carriage on which the components are supported and which is guided along the joining zone on a side of the components which faces away from the tool such that, during welding, an automatic relative movement is made possible between the stirring pin and the carriage or the shoulder surface of the tool and a support surface of the carriage which supports the components, and to a device for carrying out such a method.