Floating-Axle FSW Head With Load Cell for Axial Force Sensing
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Solution Overview
Problem
Existing friction stir welding (FSW) heads face challenges in accurately measuring axial forces, which are crucial for proper calibration and control of the welding process, often requiring multiple setups and increased costs due to the need for separate heads for rotating and stationary shoulder configurations.
Innovation Solution
A compact FSW head design featuring a floating axle and a load cell positioned beneath the head housing, allowing for accurate axial force measurement and easy transition between rotating and stationary shoulder configurations with a single operation, eliminating the need for external spindle actuators and reducing setup time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional FSW head design with fixed axle is used, then the structure is simple and easy to manufacture, but the axial force measurement accuracy is poor and collision risk increases
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed axle into a floating axle that can move axially relative to the head housing. This dynamic configuration allows the axle to self-adjust its position, reducing collision risk while enabling accurate axial force measurement through the load cell. The floating axle moves freely in the axial direction while maintaining rotational capability, resolving the contradiction between measurement precision and structural simplicity.
Solution Approach 2:
The load cell serves as an intermediary element between the floating axle and the head housing. It mediates the transmission of axial forces from the welding tool to the measurement system, enabling accurate force measurement without requiring direct rigid connection. This intermediary component resolves the contradiction by providing precise measurement capability while maintaining the flexibility of the floating axle structure.
2Adaptability or versatility
If separate heads are used for rotating and stationary shoulder configurations, then each configuration can be optimized, but the device complexity and cost increase
Solution Approach 1:
The patent applies universality by designing a single FSW head with a floating axle that can accommodate both rotating shoulder and stationary shoulder configurations. The motor assembly can drive either the axle directly (rotating shoulder) or a separate drive mechanism (stationary shoulder), making the head versatile. This eliminates the need for multiple specialized heads, reducing device complexity while maintaining configuration flexibility.
Solution Approach 2:
The floating axle design enables dynamic reconfiguration between rotating and stationary shoulder modes. The axle can transition from being directly driven to being stationary while the drive mechanism changes, allowing a single head to perform multiple functions. This dynamic adaptability resolves the contradiction between versatility and device complexity.
3Measurement precision
If the load cell is positioned far from the FSW tool, then the head housing structure is simpler, but the axial force measurement accuracy decreases
Solution Approach 1:
The patent extracts the load cell from the traditional position within the head housing and positions it externally, attached to the floating axle. This extraction allows the load cell to be positioned optimally close to the welding tool for accurate measurement while keeping the head housing structure simple. The load cell measures axial forces directly on the floating axle, eliminating the need for complex internal mounting structures.
4Productivity
If multiple setups are used for different welding configurations, then each setup can be optimized, but the loss of time and increased costs occur
Solution Approach 1:
The universal floating axle design allows a single head to perform both rotating and stationary shoulder welding operations. Operators can switch between configurations by adjusting the drive mechanism rather than changing entire heads, dramatically reducing setup time and increasing productivity. The single-head multi-functionality eliminates the time loss associated with multiple setups while maintaining optimization for each welding mode.
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 design provides improved axial force measurement accuracy, reduces the risk of collision during operations, and allows for seamless switching between welding configurations, enhancing the quality and efficiency of welds while minimizing equipment costs and operational complexity.
Implementation Method 1
the axial movement of the axle allows the axle to impart axial forces to a load cell disposed within or beneath the head housing
Implementation Method 2
Friction stir welding (FSW) is a welding process which uses heat generated from high-pressure friction to form a joint between two workpieces and/or to fix cracks in a workpiece
Data Source
AI summary
The friction stir welding head presented herein includes a head housing and an axle. The head housing extends from a top end to an open bottom end and defines a bore extending between the top end and the open bottom end. The axle that is coaxial with and rotatable within the bore. The axle is also laterally secured within the head housing and axially movable with respect to the head housing. Still further, the axle includes an engagement end that extends beyond the open bottom end of the head housing. The engagement end supports a friction stir welding tool that is configured to rotate with the axle to effectuate friction stir welding operations. The friction stir welding head may also include a load cell configured to generate load signals in response to axial movement of the axle.