Resistance Spot Welding Device Dynamic Heat Control
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Solution Overview
Problem
Resistance spot welding technologies face challenges in maintaining consistent nugget diameter due to electrode wear and disturbances such as current shunting and sheet gaps, leading to inefficient heat generation and potential splashing, especially when existing welds or surface roughness affects the welding process.
Innovation Solution
A resistance spot welding device and method that control both current and voltage, as well as electrode force, to secure a predetermined current passage area, ensuring the cumulative heat generated matches the target value, thereby maintaining a consistent nugget diameter and preventing splashing, even under conditions of electrode wear or disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the same welding current is used throughout welding operations, then initial welding quality is maintained, but nugget diameter decreases as electrodes wear
Solution Approach 1:
The welding current is dynamically adjusted based on the number of welding operations performed. The control unit increases the welding current in steps after predetermined numbers of welding operations to compensate for electrode wear, transforming the static current application into a dynamic adaptation process that maintains welding quality throughout the electrode's service life
Solution Approach 2:
The system implements feedback control by monitoring the number of welding operations and using this information to adjust the welding current. The control unit receives feedback on electrode wear status (through operation counting) and automatically modifies the welding current to maintain consistent nugget diameter, eliminating the need for manual intervention
2Manufacturing precision
If welding current is increased to compensate for electrode wear, then nugget diameter is maintained, but energy consumption increases
Solution Approach 1:
The welding current is dynamically adjusted based on the number of welding operations performed. The control unit increases the welding current in steps after predetermined numbers of welding operations to compensate for electrode wear, transforming the static current application into a dynamic adaptation process that maintains welding quality throughout the electrode's service life
Solution Approach 2:
The system changes the welding current parameter in discrete steps based on the number of welding operations. By adjusting only the current parameter (while keeping other parameters constant), the system compensates for electrode wear with minimal energy overhead, avoiding unnecessary increases in welding time or electrode force
3Manufacturing precision
If high welding current is set beforehand to compensate for current shunting, then nugget diameter is sufficient, but splashing occurs
Solution Approach 1:
The welding current is dynamically adjusted based on real-time monitoring of welding conditions and the number of operations. Rather than using a permanently high current setting, the system adapts the current level to actual needs, increasing it only when electrode wear or disturbances require compensation, thereby avoiding excessive current that would cause splashing
Solution Approach 2:
The system implements feedback control by monitoring welding conditions and adjusting the current accordingly. By detecting actual welding performance and electrode wear status, the control unit modifies the current in real-time, preventing both insufficient heating (which would reduce nugget diameter) and excessive current (which would cause splashing)
4Manufacturing precision
If electrode force is increased to improve contact area, then current density is maintained, but device complexity increases
Solution Approach 1:
The electrode force is dynamically adjusted based on the number of welding operations and detected welding conditions. The control unit modifies the electrode force in steps to compensate for contact area changes due to electrode wear, maintaining consistent current density without requiring complex real-time measurement systems
Solution Approach 2:
The system changes the electrode force parameter in discrete steps based on welding operation count and detected conditions. By adjusting only the force parameter (while keeping current and time constant), the system maintains current density consistency with minimal added complexity, avoiding the need for complex multi-parameter simultaneous 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
The solution effectively achieves a consistent nugget diameter without splashing, regardless of electrode wear or disturbances, by dynamically adjusting current, voltage, and electrode force to match the heat generation patterns of test welding conditions during actual welding.
Implementation Method 1
Heat generated from the resistance to the flow of the high welding current is utilized to obtain a spot weld
Data Source
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AI summary
A nugget of an appropriate diameter is obtained without splashing. A resistance spot welding device that joins predetermined parts to be welded includes: a storage configured to store a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume in test welding that precedes actual welding; and an adaptive controller and an electrode force controller configured to, in the case where the time variation of the instantaneous amount of heat generated per unit volume in the actual welding differs from a time variation curve stored as the target value, respectively control the current or a voltage during current passage and the electrode force to the parts to be welded to compensate for the difference within a remaining welding time so that the cumulative amount of heat generated per unit volume in the actual welding matches the cumulative amount of heat generated per unit volume stored in the storage.