Aluminum Spot Welding Control via Force Feedback
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Solution Overview
Problem
Conventional welding processes designed for steel are inadequate for aluminum due to physical and chemical differences, leading to low-quality welds with inadequate strength and structural damage due to rapid heat dissipation and a high-melting oxide film.
Innovation Solution
A welding process that uses a force sensor to measure the force between electrodes and calculates control deviations, allowing for a welding time extension with a constant current level after the initial welding time, based on the measured force deviation, to re-weld and enhance the quality of welds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional steel welding processes are used for aluminum, then the welding process is simple and familiar, but the weld quality is poor with structural cracks and air inclusions due to rapid heat dissipation
Solution Approach 1:
The patent extends the welding time parameter beyond the conventional set welding time used for steel. The welding time extension is determined based on the control deviation measured during the set welding time, allowing the welding process to be adapted for aluminum's different thermal properties without completely redesigning the process
Solution Approach 2:
The patent uses a force sensor to continuously monitor the force between welding electrodes and feeds this information back to the welding control. The control deviation calculated from this feedback is used to determine the welding time extension, creating a closed-loop control system that adapts to the actual welding conditions and material properties
2Strength
If the welding time is extended to improve weld quality, then the weld strength increases, but the welding process time and energy consumption increase
Solution Approach 1:
The welding time extension is not a fixed value but is dynamically determined based on the control deviation measured during the set welding time. This dynamic adjustment allows the welding time to be optimized for each specific welding situation, extending time only when needed to achieve the desired weld quality
Solution Approach 2:
The welding time parameter is adjusted based on the control deviation from force measurements. By changing the welding time parameter dynamically rather than using a fixed extended time, the process achieves improved weld strength while minimizing unnecessary time extension
3Manufacturing precision
If force measurement and welding time extension are implemented, then weld quality improves through re-welding, but the device complexity and control effort increase
Solution Approach 1:
The welding control system automatically determines the welding time extension based on the control deviation from force measurements without requiring external intervention. The system uses its own measurements and calculations to adjust the welding process, making the control system self-regulating and reducing the need for complex external control mechanisms
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 process enables easy and cost-effective welding of aluminum by re-working welds to improve their quality, reducing structural cracks and air inclusions, and maintaining continuous monitoring with minimal control effort.
Implementation Method 1
at least one force sensor measures a force between two welding electrodes on aluminum elements to be welded
Implementation Method 2
the welding control subjects the welding electrodes to a current of a constant level during a welding time extension
Data Source
AI summary
A welding process for the welding of aluminum includes a force sensor measuring a force between two welding electrodes on aluminum elements to be welded and transmitting its measured values to a welding control. Until the elapse of a set welding time, the welding control calculates and stores at least one absolute value and/or at least one increase in the measured force. The welding control compares the measured absolute value and/or the increase in the measured force with a reference value and/or a reference curve and calculates a control deviation from the comparison. After the elapse of the set welding time, the welding control subjects the welding electrodes to a constant current during a welding time extension that follows the set welding time, dependent on a magnitude of the control deviation that is measured at the point in time of the elapse and/or during the set welding time.