Gas-Shielded Arc Welding Control for Tip-to-Work Distance Changes
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Solution Overview
Problem
Existing gas-shielded arc welding methods struggle with unstable arc length and increased spatter due to fluctuations in tip-to-work distance during weaving, particularly when using CO2 gas mixtures and specific welding power source gradients, leading to poor welding workability and inaccurate arc tracking.
Innovation Solution
A method and system utilizing a welding control device and power source with torch-position determining means and correction-current calculating means to adjust gains based on torch position, stabilizing arc length and suppressing welding current fluctuations, even with changing tip-to-work distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gradient of the external characteristic of the welding power source is increased (made more negative), then welding current fluctuations are suppressed, but arc length fluctuates more causing self-regulating function to become ineffective
Solution Approach 1:
The invention dynamically adjusts the gradient of the external characteristic based on the detected tip-to-work distance. When the distance is small, a larger gradient (more negative) is applied to suppress current fluctuations. When the distance is large, a smaller gradient (less negative) is applied to maintain arc length control effectiveness. This dynamic adjustment resolves the contradiction by adapting the gradient value to the actual welding conditions rather than using a fixed value.
Solution Approach 2:
The invention changes the parameter (gradient of external characteristic) based on the tip-to-work distance conditions. By detecting the distance and selecting appropriate gradient values from a predetermined map, the system optimizes both current stability and arc length control for different welding scenarios, resolving the contradiction between these two competing requirements.
2Manufacturing precision
If the gradient of the external characteristic is decreased (approaches 0), then arc length self-regulating function becomes effective, but welding current fluctuates more reducing arc tracking accuracy
Solution Approach 1:
The system dynamically selects the gradient value based on real-time detection of tip-to-work distance. When distance is large, a smaller gradient (closer to 0) is selected to enhance arc length self-regulation. When distance is small, a larger gradient is selected to improve current stability and arc tracking. This dynamic selection resolves the contradiction by optimizing the gradient for each specific welding condition.
Solution Approach 2:
The invention changes the gradient parameter according to the detected tip-to-work distance conditions. By using a predetermined map that associates distance ranges with optimal gradient values, the system achieves both arc length stability and current stability under different welding conditions, resolving the contradiction between these two parameters.
3Adaptability or versatility
If generic 100% CO2 gas is used, then shielding gas availability is improved, but welding workability deteriorates with tip-to-work distance changes
Solution Approach 1:
The invention uses feedback from torch-position determining means to detect tip-to-work distance changes during welding. This feedback information is used to dynamically adjust the gradient of the external characteristic, enabling the system to maintain welding workability even when using generic 100% CO2 gas with varying tip-to-work distances, thus resolving the contradiction between gas availability and welding quality.
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
This approach maintains arc length control and suppresses welding current fluctuations, enhancing welding workability and achieving accurate arc tracking during weaving, regardless of shielding gas composition.
Implementation Method 1
gas-shielded arc welding
Implementation Method 2
shielding gas with a CO2 mixture ratio of 20% to 40% is supplied from a welding torch toward the groove
Data Source
AI summary
Gas-shielded arc welding in which the tip-to-work distance changes is configured so that fluctuations in welding current are curbed while arc length control is maintained. This is achieved with a corrected current calculating unit that includes a first controlling expression where a first gain G1 is multiplied by an instantaneous voltage error value that is the difference between an instantaneous output voltage setting value and an output voltage detection value, and/or a second controlling expression where a second gain G2 is multiplied by an average voltage error value that is the difference between an output voltage setting value and an average output voltage detection value of a pre-set period of time, determines an arc property gain G1 and/or G2 based on a torch position detection value determined by a torch position determinator, and calculates a corrected current based on the first and/or the second controlling expression.