Spot Welding Quality Check System Using Adaptive Displacement Evaluation
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Solution Overview
Problem
Existing spot welding quality check systems face challenges in accurately evaluating welding quality due to changes in pressurizing force, material thickness, and adaptive current waveforms, leading to incorrect evaluations, burdensome parameter adjustments, and lenient quality criteria.
Innovation Solution
A spot welding quality check system that includes a pair of electrodes, a displacement detecting part, a checking part using an inner function to estimate welding quality based on displacement data, a correction receiving part for operator input, and a learning part to update the function based on corrections, allowing for continuous data evaluation and adaptive parameter adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parameter adjustment is made for every welding point to account for material and thickness variations, then welding quality check accuracy is improved, but operation complexity and time consumption increase significantly
Solution Approach 1:
The system automatically identifies welding point types and selects appropriate evaluation parameters without operator intervention. The welding point type identification unit classifies each welding point, and the parameter setting unit automatically configures the corresponding evaluation parameters, enabling the system to serve itself rather than requiring manual parameter adjustment for every welding point.
Solution Approach 2:
Evaluation parameters are pre-configured for different welding point types. The system performs preliminary classification of welding points and has predetermined parameter sets ready for each type, so when a welding point is encountered, the appropriate parameters are already available without requiring on-the-spot adjustment.
2Adaptability or versatility
If adaptive control is used to change current during welding, then welding process flexibility is improved, but welding quality evaluation accuracy deteriorates due to waveform variations
Solution Approach 1:
The system dynamically adapts the evaluation process to match the actual welding current waveform. The waveform analyzing unit detects the current waveform characteristics, and the evaluation unit adjusts its evaluation criteria accordingly. This allows the system to maintain accurate evaluation even when adaptive control changes the current waveform during welding.
Solution Approach 2:
The system incorporates feedback from the actual welding current waveform to adjust the evaluation process. The waveform analyzing unit continuously monitors the current waveform, and this information feeds back to the evaluation unit, which modifies its evaluation criteria to account for waveform variations caused by adaptive control.
3Productivity
If pressurizing force is changed during current application, then welding process control is improved, but displacement-based quality measurement becomes inaccurate
Solution Approach 1:
The system transitions from using displacement as the sole evaluation parameter to using multiple parameters including welding current, voltage, and time. This parameter change allows the system to evaluate welding quality accurately even when pressurizing force varies during current application, as these alternative parameters are not affected by pressurizing force changes in the same way displacement is.
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 system enables accurate and adaptive evaluation of welding quality, reducing manual adjustments and ensuring stringent criteria, even in adaptive current conditions, thereby improving checking accuracy and efficiency.
Implementation Method 1
measuring a degree of thermal expansion of an object to be welded by using an amount of displacement of a value of an encoder attached to an actuator when current is applied to the actuator
Implementation Method 2
measuring a degree of contraction of the material by using an amount of displacement of a value of the encoder before and after current is applied to the actuator
Implementation Method 3
resistance welding by pressurizing an object to be welded by using an electrode
Data Source
AI summary
A spot welding quality check system, which can be easily used and can be adapted to various situations. The check system has: a pair of electrodes configured to move toward or away from each other and apply current to a workpiece while pressurizing the workpiece; a displacement detecting part which detects an amount of displacement between the electrodes during spot welding; a checking part which estimates as to whether welding quality is good or poor by using an inner function, based on the detected amount of displacement; a correction receiving part which receives a correction by an operator regarding the estimated welding quality; and a learning part which updates the inner function based on an estimation result when the correction receiving part does not receive the correction, and updates the inner function based on a content of the correction when the correction receiving part receives the correction.