Thin Sheet Arc Welding Control for Stable Low-Heat Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In thin sheet welding, pulse arc welding with high heat input tends to cause burn through and strain, leading to undercut and instability in the arc, which hinders productivity and welding quality, especially when high-speed welding is performed with gaps between base materials.
Innovation Solution
An arc welding control method that alternately repeats periods of forward and reverse feeding of the welding wire, with distinct heat input periods to manage short-circuit and arc phases, reducing heat input during the second phase by decreasing welding current after short-circuit release and maintaining stable arc conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse arc welding with large heat input is used, then welding speed can be improved, but burn through and strain increase causing undercut and arc instability
Solution Approach 1:
The patent applies periodic action by implementing pulse arc welding with alternating high-current arcs and short-circuit periods. The welding current is periodically varied between a first level during arc periods and a second level during short-circuit periods, creating a rhythmic cycle that controls heat input accumulation. This periodic modulation prevents continuous high heat input that causes burn through while maintaining sufficient welding speed through the high-current arc phases.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting welding current levels between two distinct states: a first current level during arc periods and a second current level during short-circuit periods. The invention also modifies arc length parameters by controlling wire feed speed to maintain a short arc during high-current periods. These parameter variations enable control over both welding speed and heat input distribution, resolving the contradiction between productivity and reliability.
2Object-affected harmful factors
If welding current is reduced to prevent burn through, then heat input decreases, but arc becomes unstable
Solution Approach 1:
The patent resolves this contradiction through periodic action by cycling between high-current arc periods that stabilize the arc and short-circuit periods that reduce heat input. During arc periods, the first welding current level maintains arc stability, while during short-circuit periods, the second welding current level prevents burn through. This temporal separation of functions allows the system to achieve both arc stability and burn through prevention.
Solution Approach 2:
The invention applies dynamics by making the welding current adaptive rather than static. The control system dynamically switches between two current levels based on the welding phase (arc or short-circuit), and also dynamically adjusts wire feed speed to maintain appropriate arc length. This dynamic response enables the system to maintain arc stability when needed while reducing heat input when necessary, preventing burn through without sacrificing arc reliability.
3Productivity
If high-speed welding is performed, then productivity improves, but undercut is easily produced
Solution Approach 1:
The patent addresses this contradiction through periodic action by implementing cycles of high-current arcs followed by short-circuit periods. The high-current arc periods provide sufficient heat input for high-speed welding, while the subsequent short-circuit periods allow heat dissipation and prevent excessive heat accumulation that causes undercut. This rhythmic pattern enables maintenance of welding speed while controlling heat input to preserve welding quality.
Solution Approach 2:
The invention uses parameter changes to resolve the speed-quality contradiction. By varying welding current between two levels and adjusting wire feed speed dynamically, the system can maintain high welding speed during arc periods while controlling heat input during short-circuit periods. This parameter modulation ensures that even at high welding speeds, the cumulative heat input remains within limits that prevent undercut, thereby maintaining manufacturing precision.
4Productivity
If thin sheet welding is performed with gaps between base materials, then yield improves, but burn through risk increases
Solution Approach 1:
The patent applies periodic action to manage heat input in gap welding of thin sheets. The alternating cycle of high-current arcs and short-circuit periods creates controlled heat accumulation and dissipation patterns. During arc periods, heat is concentrated to bridge gaps and achieve penetration, while during short-circuit periods, heat is reduced to prevent burn through of the thin sheet material. This temporal modulation of heat input enables successful welding of gapped thin sheets with improved yield.
Solution Approach 2:
The invention employs parameter changes by dynamically adjusting welding current between two distinct levels and modifying wire feed speed to maintain short arc length. During arc periods, the first current level provides sufficient energy to bridge gaps between base materials, while during short-circuit periods, the second current level prevents excessive heat input that would cause burn through. These parameter variations enable the system to accommodate gap welding of thin sheets while maintaining high yield and preventing burn through.
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 method reduces heat input, suppresses burn through, improves gap tolerance, and prevents undercut, thereby enhancing welding quality and productivity during high-speed thin sheet welding.
Implementation Method 1
generating an arc between a welding wire that is a consumable electrode and a base material that is a welding subject
Implementation Method 2
each of the first heat input period and the second heat input period includes a short-circuit period
Data Source
AI summary
In thin sheet welding, when a heat input amount relative to a sheet thickness is too large, a welding defect such as a deviation from aim due to occurrence of a strain or burn through may easily occur. When a welding current is decreased to reduce the heat input amount, there is an issue in which an arc tends to become unstable. In arc welding in which short-circuit and arcing are repeated, first heat input period (Th) and second heat input period (Tc) having a heat input amount less than that of first heat input period (Th) are periodically repeated and a welding current during an arc period in second heat input period (Tc) is decreased to extinguish the arc. This reduces the heat input amount into a welding object and suppresses burn through or a strain upon welding, while making the arc stable.