Force-Sensing Electrospindle for Precise Friction Stir Welding
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Solution Overview
Problem
Existing friction stir welding (FSW) processes face challenges with high investment costs, manufacturing lead times, limited welding angles, and reduced precision due to the rigidity and size constraints of gantry-type machines and industrial robots, particularly when dealing with structurally hardened aluminum alloys, and require improved force control mechanisms for optimal weld quality.
Innovation Solution
An electrospindle equipped with three compact and cost-effective beam-type force sensors, a ball joint, and a multi-axis sensor system for precise force measurement and calibration, allowing for force control in all three directions, integrated with a compact design for seamless fluid and cable routing, and temperature measurement capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gantry-type machines are used for FSW, then welding precision and rigidity are improved, but investment cost and manufacturing lead time increase significantly
Solution Approach 1:
The patent introduces an intermediary solution by adapting electrospindles designed for machining centers to FSW applications. This intermediary approach allows using existing high-precision machining equipment for welding purposes, avoiding the need to build expensive dedicated gantry-type FSW machines while maintaining welding precision through the rigid structure and precision capabilities of machining center electrospindles
Solution Approach 2:
The patent applies universality by making electrospindles suitable for multiple functions - both traditional machining operations and friction stir welding. The electrospindle design incorporates universal features that allow it to perform both cutting and welding functions, eliminating the need for separate specialized equipment and reducing overall investment cost
2Ease of manufacture
If industrial robots are used for FSW, then investment cost is reduced, but welding precision and rigidity deteriorate due to tool deflection
Solution Approach 1:
The patent applies dynamics by implementing a dynamic compensation system that measures actual tool deflection forces during welding using integrated sensors, then uses control algorithms to compensate for these deflections in real-time. This allows maintaining welding precision despite using lighter, more cost-effective robotic systems by dynamically adjusting for rigidity limitations
Solution Approach 2:
The patent incorporates feedback mechanisms through force sensors and position sensors that continuously monitor welding parameters and tool deflection. This feedback is used by the control system to adjust welding parameters and compensate for deflection, maintaining precision without requiring the extreme rigidity of gantry machines, thus reducing investment cost
3Adaptability or versatility
If traditional FSW tools are used, then welding capability is achieved, but force control precision deteriorates without adequate sensing
Solution Approach 1:
The patent merges force sensing capabilities directly into the electrospindle structure by integrating force sensors into the electrospindle housing. This combination allows simultaneous measurement of multiple force components (Fx, Fy, Fz) at the tool interface, providing precise force control while maintaining full welding capability and enabling real-time adjustment of welding parameters
4Volume of moving object
If compact electrospindle design is implemented, then accessibility and robot load capacity are improved, but force measurement capability may be limited
Solution Approach 1:
The patent resolves the space constraint by arranging force sensors in a compact three-dimensional configuration within the electrospindle housing. Multiple force components are measured using sensors positioned at different spatial locations and orientations, allowing full force measurement capability in a compact volume that maintains robot load capacity and accessibility
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 provides economical and practical force control, enhances welding precision, reduces tool deflection, and improves accessibility, while maintaining high torque and torque capacity, suitable for both FSW and machining applications.
Implementation Method 1
at least three force sensors, each sensor being interposed between the base and the support and configured to measure only a force exerted by the support on the base in a direction parallel to an axis of rotation of the shaft
Implementation Method 2
The support is connected to the base by a ball joint
Implementation Method 3
a shoulder that heats the material by friction against the surface of the parts to be welded
Implementation Method 4
a pin that kneads the material to create a joint between the parts
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to an electric spindle (2) which comprises a base, a support connected to the base, a shaft rotatably mounted relative to the support, at least three force sensors (90), each sensor (90) being inserted between the base and the support and being configured in such a way as to measure only a force exerted by the support on the base in a direction parallel to an axis of rotation of the shaft, and means capable of calculating forces exerted on a tool (36) rigidly connected to the shaft in the direction (Z) parallel to the axis and in two directions perpendicular to the axis on the basis of the forces measured by the sensors.