Spot Welding Method With Peripheral Pressurizing Member
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Solution Overview
Problem
Existing spot welding methods face challenges in expanding the optimum current range to prevent splash generation and ensure sufficient nugget diameter without complex control mechanisms.
Innovation Solution
A spot welding method using a pair of electrodes and a pressurizing member to apply a welding current, where the pressurizing member pressurizes the periphery of the electrodes at a specific load and distance, and post-energization steps are implemented to control cooling and tempering, preventing expulsion and surface flash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the current value is excessively high, then the nugget diameter becomes large, but splash is generated and joint strength fluctuates
Solution Approach 1:
The patent applies preliminary pressurization to the metal sheets before and during the welding process. By pre-compressing the sheets with a pressurizing member, the material becomes more resistant to splash generation when high current is applied, allowing larger nugget diameters without the harmful splash effect that would normally limit current intensity.
Solution Approach 2:
The patent changes the pressure parameter by introducing a pressurizing member that applies additional force to the metal sheets. This parameter change (increased pressure) allows the system to tolerate higher current values without splash, effectively expanding the safe operating range for current intensity while maintaining joint strength.
2Object-generated harmful factors
If the current value is excessively low, then the nugget diameter is small, but joint strength is insufficient
Solution Approach 1:
The patent changes the pressure parameter to compensate for low current values. By increasing the pressure applied to the metal sheets, the system achieves adequate joint strength even when the current is reduced, allowing operation at lower current levels without sacrificing weld quality.
3Strength
If a two-step energization method is used to suppress splash and secure nugget diameter, then welding quality improves, but control complexity and welding time increase
Solution Approach 1:
The patent introduces a pressurizing member as an intermediary element that physically mediates between the electrodes and the metal sheets. This mechanical intermediary provides the necessary control function (suppressing splash, maintaining pressure) without requiring complex electrical control sequences, thereby simplifying the overall control system while maintaining weld quality.
4Strength
If high current is applied to expand nugget diameter, then joint strength improves, but splash generation increases
Solution Approach 1:
The patent applies preliminary pressurization to the metal sheets before high current is applied. This pre-compression prepares the material to withstand the high current without generating splash, allowing the system to achieve large nugget diameters and high joint strength while suppressing the harmful splash effect that would normally occur at such current levels.
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 method effectively expands the optimum current range, preventing splash generation and enhancing the strength of the spot weld joint by controlling the cooling rate and tempering process.
Implementation Method 1
pressurizing the periphery of each of the electrodes by the pressurizing member at a load of 5 to 1000% of a load given by the pair of electrodes
Implementation Method 2
A current is then applied to the stacked section to melt a joint interface of the metal sheets through resistance heating
Implementation Method 3
melt a joint interface of the metal sheets through resistance heating
Implementation Method 4
the members are prevented from being warped due to rapid cooling
Data Source
AI summary
A spot welding method joins metal sheets by: clamping a stacked section of two or more stacked metal sheets with a pair of electrodes at a load of 100 N or more; applying pressure around the electrodes at a load, which is 5-1000% of the load due to the pair of electrodes, using a pressurizing member, which applies pressure on the stacked section in regions that are 20% or more of the total outer circumference of the electrode tips and for which the continuous regions of the entire outer circumference of the electrode tips that are not pressed are 30% or less (including 0%) of the entire outer circumference of the electrode tips; and passing welding current from the electrodes to the stacked section.