Spot Welding Pre-Conditioning for Oxide Film Resistance Control
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Solution Overview
Problem
Existing spot welding machines face challenges with nonconducting oxide films on workpieces, leading to high resistance and excessive overheating, which are not effectively addressed by static solutions that do not adapt to varying workpiece and electrode conditions.
Innovation Solution
A welding machine with an automated and iterative pre-conditioning process that adapts voltage, current, and duration of welding pulse portions based on real-time measurements to reduce resistance at the workpiece to a desirable level, ensuring optimal conditions for spot welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a welding current is applied at different levels during three specific steps with cooling times between each step, then the electrical resistance is reduced to a consistent low value, but the welding process becomes static and not adaptable to different workpiece and electrode conditions
Solution Approach 1:
The patent transforms the static multi-step welding process into a dynamic adaptive process by continuously measuring voltage and current during the welding operation. The control unit automatically adjusts welding parameters in real-time based on measured resistance values, enabling the system to adapt to different workpiece and electrode conditions while maintaining consistent low electrical resistance.
Solution Approach 2:
The patent implements a feedback mechanism where voltage and current are continuously measured during welding, and the control unit uses this feedback information to automatically adjust welding parameters. This closed-loop control ensures both consistency in electrical resistance and adaptability to varying workpiece and electrode conditions.
2Temperature
If large, flat welding electrodes are used to reduce current density and heating, then electrode/workpiece overheating is reduced, but manufacturing efficiency is negatively impacted
Solution Approach 1:
The patent dynamically changes welding parameters (current, voltage, pulse duration) in real-time based on measured resistance values. This allows the use of standard-sized electrodes while maintaining optimal temperature control through adaptive parameter adjustment, thereby preserving manufacturing efficiency.
Solution Approach 2:
The patent employs periodic welding pulses with adaptive timing based on resistance measurements. This periodic action with variable parameters allows sufficient cooling time while maintaining productivity, avoiding the need for continuously large, flat electrodes.
3Adaptability or versatility
If an automated adaptive pre-conditioning process is implemented with real-time measurements, then flexibility and adaptability are improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the control unit, which performs both measurement and control tasks. The same control unit that manages the welding process also acquires voltage and current measurements and automatically adjusts parameters, eliminating the need for separate complex measurement and control systems.
Solution Approach 2:
The welding system performs self-diagnosis and self-adjustment by continuously measuring its own operating parameters and automatically modifying welding conditions based on real-time feedback. This self-service capability reduces the need for external complex control systems while maintaining high adaptability.
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 adaptive pre-conditioning scheme effectively reduces resistance at the workpiece, preventing overheating and ensuring high-quality welds by dynamically adjusting parameters to meet the specific conditions of different workpieces and electrode assemblies.
Implementation Method 1
electric welding current is supplied through the material via the welding electrodes
Implementation Method 2
a possible presence of e.g. a nonconducting oxide film on the workpiece, resulting in an undesirably high resistance between the workpiece and the electrodes
Data Source
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AI summary
The present disclosure generally relates to a welding machine adapted for performing a spot welding process on a workpiece, wherein the welding machine is specifically adapted for automatically applying pre-conditioning a welding pulse portion to the workpiece prior to performing the spot welding process. The present disclosure also relates to a corresponding method and computer program product.