Friction Spot Joining Heat-Input Control for Stable Weld Quality
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Solution Overview
Problem
The friction spot joining method faces challenges in maintaining consistent joining quality and extending tool life due to variations in tool and plate surface conditions, leading to potential overheating and reduced tool longevity.
Innovation Solution
A friction spot joining device equipped with an advance-retreat drive and rotation drive, controlled by a controller that calculates an integrated value based on the tool's current value and driving time to ensure uniform heat input and stabilize the joining process, thereby reducing variations in joining quality and tool wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the tool is pushed into the plates for a fixed period of time, then the joining process is simple to control, but the joining quality varies due to changes in surface conditions and frictional coefficient
Solution Approach 1:
The control system monitors the actual pushing time and adjusts the tool rotation speed dynamically based on the elapsed time, creating a feedback loop that maintains consistent heat input and friction stirring despite variations in surface conditions
Solution Approach 2:
The system changes the rotation speed parameter as a function of time during the pushing process, ensuring that the integrated heat input remains constant even when surface conditions vary, thereby maintaining uniform joining quality
2Productivity
If the tool rotation speed is increased to improve productivity, then more joining points can be processed, but the tool overheats and wears out faster
Solution Approach 1:
The system implements periodic adjustment of rotation speed during the pushing process, varying the speed in a controlled manner to maintain optimal heat input levels and prevent tool overheating while sustaining high productivity
Solution Approach 2:
The tool continues to rotate and push into the plates continuously, but the rotation speed is modulated to maintain consistent heat generation, ensuring continuous productive operation without overheating
3Manufacturing precision
If the pushing time is extended to ensure complete joining, then joining quality improves, but the tool is exposed to friction and heat longer causing excessive wear
Solution Approach 1:
The system dynamically adjusts the rotation speed during the pushing process based on real-time feedback, optimizing the balance between achieving complete joining and minimizing tool exposure to friction and heat
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 stabilizes the joining quality and extends the tool's life by ensuring consistent heat input and reducing operator burden in adjusting the device, even when tool or plate states change, thus preventing overheating and wear.
Implementation Method 1
a tool of a friction spot joining device is pushed into the pair of plates which are overlapped with each other while the tool is rotated
Implementation Method 2
friction spot joining method is known as a method of mutually joining a pair of plates
Data Source
AI summary
A friction spot joining device configured to carry out friction spot joining of a pair of plates includes an advance-retreat drive configured to advance and retreat a tool to/from the plates a rotation drive configured to rotate the tool, and a controller configured to control the advance-retreat drive and the rotation drive. The controller executes a joining control in which the tool is caused to give pressure to the plates while the tool is rotated so that the tool is pushed into the plates, and a separating control in which the tool is separated from the plates when an integrated value (P=ID×ΔT) calculated using a current value (ID) of the rotation drive during the joining control and a driving period of time (ΔT) during the joining control is determined to be reached a target value.