Friction Stir Spot Joining Tool Breakage Detection in Continuous Welding
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Solution Overview
Problem
The existing friction stir spot joining method often results in tool breakage during continuous joining operations, leading to potential joining failures and damage to both the tool and the plate members, due to undetected tool breakage between joining positions.
Innovation Solution
A friction stir spot joining apparatus equipped with a breakage detection unit that monitors the change in pressurization force and electric conduction to detect tool breakage before proceeding to the next joining position, preventing further damage by controlling the tool's operation based on detected issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tool is continuously used for friction stir spot joining at multiple joining positions, then productivity is improved, but the risk of tool breakage increases and undetected breakage causes joining failures
Solution Approach 1:
The breakage detection unit performs detection at predetermined positions before actual friction stir spot joining operations. This preliminary detection ensures that tool breakage is identified before it causes joining failures, allowing the system to maintain high reliability while continuing productive operations.
Solution Approach 2:
The breakage detection unit provides real-time feedback on tool condition by monitoring pressurization force and electric conduction during the joining process. This feedback mechanism enables continuous productivity while maintaining tool integrity through immediate detection of breakage conditions.
2Reliability
If tool breakage is detected by monitoring pressurization force during joining operations, then tool integrity is maintained, but the device complexity increases
Solution Approach 1:
The breakage detection unit serves multiple functions: it monitors pressurization force, detects electric conduction changes, and determines tool breakage status. By consolidating these detection functions into a single multi-functional unit, the system achieves reliable tool breakage detection without proportionally increasing device complexity.
Solution Approach 2:
The tool itself provides detection information through its own operational characteristics (pressurization force requirements and electric conduction properties). The breakage detection unit utilizes these inherent tool properties for self-diagnosis, eliminating the need for separate complex detection mechanisms.
3Strength
If the tool is pushed into the plate members for joining operations, then joining strength is achieved, but tool breakage may occur during the pushing process
Solution Approach 1:
The breakage detection unit performs detection at predetermined positions before the tool is pushed into the plate members for joining. This preliminary detection identifies potential tool weaknesses before they result in breakage during the high-stress joining operation, ensuring both joining strength and tool safety.
Solution Approach 2:
The breakage detection unit continuously monitors pressurization force during the tool pushing and joining process. When abnormal pressurization force indicating tool breakage is detected, the system provides feedback to stop operations, preventing tool breakage while maintaining joining strength through proper process control.
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 effectively prevents joining failures and apparatus damage by accurately detecting tool breakage, ensuring safe and successful continuous friction stir spot joining across multiple positions.
Implementation Method 1
The breakage detection unit is configured to detect breakage of the tool based on the change amount of pressurization force with which the tool pressurizes the second plate member in the interval from when the distal end of the tool comes into contact with the second plate member to when the distal end of the tool is disposed at the predetermined pushed position
Implementation Method 2
a friction stir spot joining method (Friction Spot Joining) is known. In the case of joining a pair of plate members by this method, for example, as disclosed in PTL 1, a tool of a friction stir spot joining apparatus is pushed into a pair of overlaid plate members while being rotated
Data Source
AI summary
A friction stir spot joining apparatus includes a tool configured to be brought into contact with or separated from a surface of a second plate member on the opposite side to a first plate member of the first and second plate members that are overlaid on each other, a driving unit configured to rotationally drive the tool around its axis, a position adjusting unit configured to adjust a relative position between the tool and the second plate member, a control unit configured to control the driving unit and the position adjusting unit, and a breakage detection unit configured to detect breakage of the tool by controlling the control unit to dispose the tool at a contact position with the second plate member or a predetermined pushed position at one joining position.