Short-Circuit Welding Cycle Control for Stable High-Frequency Penetration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing short-circuit welding processes experience instabilities and reduced quality at higher welding speeds, particularly failing to achieve high welding frequencies and sufficient penetration for workpieces up to 3 mm thick.
Innovation Solution
A short-circuit welding process with regulated welding current and conveying speed, where the short-circuit phase is ended after reaching a reverse end speed within 3 ms and repeated every 8 ms at the latest, and the forward end speed is reduced before the start of the short-circuit phase, achieving a welding frequency of greater than 125 Hz by optimizing the duration and speed of both phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional short-circuit welding processes are used, then welding can be performed on workpieces, but instabilities occur at higher welding speeds leading to reduced weld quality
Solution Approach 1:
The patent applies dynamic control of the electrode feed rate during the welding cycle. The feed rate is varied continuously: reduced during the arc phase to allow proper arc formation and heat input, then increased during the short-circuit phase to achieve rapid material transfer and stabilize the process at higher welding speeds. This dynamic adjustment resolves the contradiction by adapting the feed rate to the specific phase requirements.
Solution Approach 2:
The patent changes the feed rate parameter as a function of time and welding phase. By reducing the feed rate during the arc phase and increasing it during the short-circuit phase, the process maintains stability across a wider range of welding speeds. This parameter modulation allows the welding process to remain stable even at higher overall welding speeds, thereby improving both speed and reliability.
2Productivity
If welding frequency is increased to improve productivity, then welding speed increases, but penetration depth becomes insufficient for workpieces up to 3 mm thick
Solution Approach 1:
The patent utilizes periodic welding cycles with distinct arc phases and short-circuit phases. The arc phase provides sustained heat input for proper penetration, while the short-circuit phase enables rapid material transfer. By optimizing the duration and characteristics of each phase within the periodic cycle, the process achieves both high welding frequency and sufficient penetration depth for thick workpieces.
Solution Approach 2:
The patent ensures continuous useful action by maintaining a high welding frequency with optimized phase durations. The arc phase continuously provides heat for penetration, while the short-circuit phase continuously transfers material. This continuous alternation between heating and material transfer phases ensures both adequate penetration and high productivity, even at welding frequencies corresponding to cycles of 8 ms or less.
3Quantity of substance
If the short-circuit phase duration is extended to improve material transfer, then welding frequency decreases, but spatter increases
Solution Approach 1:
The patent applies the principle of rushing through the short-circuit phase by minimizing its duration while maximizing material transfer efficiency. The feed rate is sharply increased during this phase to quickly complete the short-circuit event, reducing the time available for spatter formation. This rapid completion of the short-circuit phase achieves high material transfer rates while minimizing spatter generation.
Solution Approach 2:
The patent changes the feed rate parameter dynamically during the short-circuit phase to optimize both material transfer and spatter reduction. By sharply increasing the feed rate during this phase, the process achieves rapid material transfer in a shortened time window, thereby reducing spatter while maintaining high material transfer efficiency.
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 ensures high stability and quality with increased welding speed, allowing for efficient penetration of up to 3 mm thick workpieces, with a welding frequency that can reach up to 170 Hz, ensuring spatter-free operation and consistent heat input.
Implementation Method 1
a welding current is regulated or set such that the short-circuit phase ends after reaching the reverse terminal velocity and after a maximum of 3 ms... the arc phase, the electrode is advanced and the arc imparts heat to the workpiece or the electrode
Implementation Method 2
The welding voltage is used, in particular, to detect a short circuit between the electrode and the workpiece
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a short circuit welding method with successive welding cycles (SZ) with a respective arc phase (LB) and a respective short circuit phase (KS). At least the welding current (I) and feed speed (v) welding parameters (P) of a melting electrode (9) are regulated, and the electrode (9) is fed in the direction of a workpiece (14) at a specified forward final speed (vVe) at least during a part of the arc phase (LB) and away from the workpiece (14) at a specified rearward final speed (vRe) at least during a part of the short circuit phase (KS). The invention also relates to a device (1) for carrying out such a short circuit welding method. According to the invention, a change in the feed speed (dv/dt) and a rearward final speed (vRe) are specified and a welding current (I) is regulated such that the short circuit phase (KS) ends after the rearward final speed (vRe) is reached and after 3 ms at the latest and is repeated every 8 ms at the latest. The welding parameter (P) is regulated such that the duration of the welding cycle (SZ) ≤ 8 ms, resulting in a welding frequency (f) ≥ 125 Hz.