Squeezing Detection Control for Consumable Electrode Arc Welding
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Solution Overview
Problem
Conventional squeezing detection control methods in consumable electrode arc welding experience delays in detecting arc recurrence due to low-pass filtering, leading to unstable welding conditions and increased spattering, especially in middle-to-high current range welding where short-circuiting occurs irregularly and droplet size varies widely.
Innovation Solution
A method that rapidly decreases the welding current upon detection of a squeezed droplet by monitoring the differential value of welding voltage or resistance, and increases the current upon arc recurrence detection without delay, using a second-order differential value to determine the squeeze period's nature, thereby stabilizing the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-pass filtering is applied to detect arc recurrence, then noise is reduced, but detection delay occurs leading to unstable welding conditions and increased spattering
Solution Approach 1:
The patent segments the welding current control into two distinct phases: a first control period using low-pass filtering for stable noise-reduced detection, and a second control period using unrestricted differential calculation for immediate arc recurrence detection. This temporal segmentation allows each method to operate in its optimal regime without compromise.
Solution Approach 2:
The patent dynamically switches between two different control strategies based on the welding state. The control method adapts by using different filtering approaches at different times - low-pass filtering during normal operation and rapid differential detection during critical arc recurrence moments - optimizing performance for each specific condition.
2Productivity
If welding current is not rapidly decreased upon squeezed droplet detection, then welding continuity is maintained, but spattering increases due to high current at arc recurrence
Solution Approach 1:
The patent performs preliminary detection of the squeezed droplet state during the short-circuit period and prepares for current reduction in advance. By detecting the precursor condition (squeezed droplet) before arc recurrence occurs, the system can proactively reduce current to prevent spattering while maintaining welding continuity.
Solution Approach 2:
The patent uses real-time feedback from monitoring the differential value of welding voltage or resistance to detect squeezed droplet formation. This feedback mechanism triggers automatic current reduction, creating a closed-loop control system that responds to actual welding conditions to prevent spattering.
3Device complexity
If conventional detection methods are used, then system complexity is low, but detection precision is insufficient for irregular short-circuiting in middle-to-high current range
Solution Approach 1:
The patent implements periodic control with two distinct periods: a first period using low-pass filtered signals for general monitoring, and a second period using rapid differential calculation for precise arc recurrence detection. This periodic switching enables the system to maintain low overall complexity while achieving high precision when needed.
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 enables immediate adjustment of welding current at arc recurrence, preventing short arc lengths and re-short-circuiting, thereby stabilizing the welding state and reducing spattering, particularly in middle-to-high current range welding.
Implementation Method 1
squeezing or constriction 1b develops in an upper portion of the droplet 1a due to an electromagnetic pinch caused by the welding current Iw passing through the droplet 1a
Implementation Method 2
During the arc period Ta, the tip of the welding wire 1 is melted to form a droplet 1a, and the base metal 2 is also melted
Data Source
AI summary
A squeezing detection control method is provided for consumable electrode arc welding in which a cycle of arc generation and short-circuiting is repeated between a consumable electrode and a base metal. First, squeezed droplet is detected as a premonitory sign of arc recurrence at the end of the short-circuiting. This detection is based on a fact that a squeeze detection reference value is attained by a differential value of the voltage or resistance between the consumable electrode and the base metal. Then, a welding current supplied to a short-circuit load is rapidly decreased upon detection of the squeezed droplet. Upon recurrence of the arc, the welding current is increased. This arc recurrence is detected by a fact that the differential value attains an arc recurrence reference value which is greater than the squeeze detection reference value.