Spot Welding Join Detection Using Resistance and Press Force
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Solution Overview
Problem
Conventional spot welding equipment detects joining of the spot welding part to the electrode by resistance, but this method can cause the electrode to fall out due to the resistance acting on it during separation.
Innovation Solution
A welding determination method that calculates a first index value based on resistance and a second index value based on pressurizing force, allowing determination of electrode joining without relying on separation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance detection is used to determine electrode joining, then joining detection capability is improved, but electrode stability deteriorates due to electrode ejection
Solution Approach 1:
The patent performs resistance measurement during the current application phase (before electrode separation) rather than during separation. By measuring resistance at timing when current is flowing through the workpiece, the system obtains joining information before the electrode is ejected, thus maintaining both detection capability and electrode stability
Solution Approach 2:
The patent replaces the conventional mechanical resistance detection method (measuring resistance during electrode separation) with an electrical measurement method performed during current application. This substitution allows resistance measurement without relying on the mechanical separation process, eliminating the electrode ejection problem while maintaining measurement functionality
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
Enables accurate determination of electrode joining during spot welding without causing electrode ejection, improving operational safety and reliability.
Implementation Method 1
a current applied using the pair of electrodes so that the workpiece is melted
Implementation Method 2
The workpiece made by laminating a plurality of metal sheets is clamped under pressure by the pair of electrodes
Data Source
AI summary
A welding determination method is provided, which determines whether a spot welding part is joined to an electrode without using resistance generated when separating the electrode from a workpiece. In the method, the workpiece made by laminating multiple metal sheets is clamped under pressure by a pair of electrodes and melted by a current applied, and after that the conduction is stopped to hold the workpiece in a pressurized state to determine whether the joining occurs. The method includes the steps of: deriving resistance between the pair of electrodes and pressurizing force by the pair of electrodes during conduction to the workpiece; and determining whether the spot welding part is joined to the electrodes based on a first index value calculated using the derived resistance and resistance in an ideal welding, and on a second index value calculated using the derived pressurizing force and pressurizing force in the ideal welding.