Friction Stir Joining Route Control for Uneven Metal Surface Heights
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Solution Overview
Problem
Existing automatic joining systems face challenges in performing friction stir joining of metallic members with front surfaces at different height positions, leading to risks of burr formation, undercut, and root flaws due to alignment issues and temperature-related defects.
Innovation Solution
An automatic joining system that includes a fixing device, a friction stir device with a rotating tool featuring a base end side pin and a tip end side pin, and a controlling device that sets a modified moving route based on the ridge line position and height differences to maintain a predetermined aiming angle and press a plastic fluidized material, preventing burr and undercut formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If friction stir joining is performed on metallic members with different height positions using a conventional rotating tool, then the joining process can be completed, but burrs, rough joining front surfaces, and undercuts occur due to tool deviation
Solution Approach 1:
The patent applies preliminary action by measuring the ridge line position of the first metallic member before the friction stir joining process, and using this measurement data to pre-calculate and set the target moving route and modified moving route. This preliminary positioning action ensures the rotating tool follows the correct path even when joining members with different height positions, preventing burrs and undercuts while maintaining high joining speed
Solution Approach 2:
The patent implements dynamics by creating a flexible moving route system that adapts to the actual workpiece geometry. The target moving route is calculated based on measured ridge line positions, and a modified moving route is generated that compensates for height differences between metallic members. This dynamic route adjustment allows the rotating tool to maintain proper engagement angle and position throughout the joining process, ensuring high surface quality without sacrificing productivity
2Ease of operation
If the rotating tool position is slightly deviated when joining metallic members with different height positions, then the joining process continues, but root flaws occur due to tool shifting from higher to lower height position
Solution Approach 1:
The patent applies feedback by measuring the actual ridge line position of the first metallic member before joining, using this measurement information to calculate the target moving route and modified moving route. This feedback loop ensures the rotating tool's path is precisely adjusted to the actual workpiece geometry, preventing tool shifting from higher to lower height positions and eliminating root flaws while maintaining operation continuity
Solution Approach 2:
The patent performs preliminary measurement of the ridge line position and preliminary calculation of the moving route before the joining process begins. This preliminary action establishes the correct tool path in advance, preventing position deviations and root flaws during the actual joining operation while ensuring smooth and continuous operation
3Device complexity
If a single pin rotating tool is used for friction stir joining, then the device structure is simple, but the tool cannot effectively press plastic fluidized material to prevent burrs and undercuts
Solution Approach 1:
The patent applies segmentation by dividing the rotating tool's pin structure into multiple segments: a base end side pin and a tip end side pin formed continuously to the base end side pin. The base end side pin features a greater taper angle and includes a stepwise pin step portion with a stepped bottom surface. This segmented design allows different portions of the pin to perform different functions: the base end side pin presses and controls the plastic fluidized material to prevent burrs and undercuts, while the tip end side pin completes the joining process
Solution Approach 2:
The patent implements local quality by giving different geometric characteristics to different parts of the rotating tool. The base end side pin has a greater taper angle and includes a stepwise pin step portion with a stepped bottom surface specifically positioned to press the plastic fluidized material. The tip end side pin has a smaller taper angle. This local differentiation of tool geometry allows the base end side pin to effectively control material flow and prevent surface defects, while maintaining overall tool simplicity
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 system ensures accurate friction stir joining of metallic members with different height positions, preventing burr and undercut formation while maintaining joining quality and preventing root flaws.
Implementation Method 1
a rotating tool performing friction stir and performs friction stir joining of the butting portion
Implementation Method 2
performing friction stir joining of the butting portion
Implementation Method 3
pressing a plastic fluidized material by a stepped bottom surface of the pin step portion
Data Source
AI summary
The automatic joining system includes: a fixing device; a friction stir device; a measuring unit; and a controlling device, in which a rotating tool includes a base end side pin and a tip end side pin formed continuously to the base end side pin, the controlling device sets a target moving route along which the rotating tool moves when friction stir joining of a butting portion is performed, based on a ridge line position before the friction stir joining is performed, and also sets a modified moving route at a position displaced toward a first metallic member side in substantially parallel with respect to the target moving route, and the friction stir device controls the rotating tool to move along the modified moving route and thereby performing the friction stir joining along the target moving route.