Arc Welding Control with Cooling Cycles for Stable Scaly Beads
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Solution Overview
Problem
Existing methods of arc welding with consumable electrodes, such as alternating short-circuit and pulse welding periods, suffer from spattering and unstable heat input, leading to irregular bead geometry and appearance in scaly beads.
Innovation Solution
A method that sequences short-circuit welding, pulse welding, and cooling periods to control heat input, with the welding wire fed alternately forward and backward during short-circuit welding and at a constant speed during pulse welding, and includes a cooling period with zero heat input to achieve precise control of bead geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If short-circuit welding is used to reduce heat input and prevent burn-through, then burn-through is reduced, but spattering increases due to irregular short circuits
Solution Approach 1:
The patent applies periodic action by alternating between short-circuit welding periods and pulse welding periods in a cyclic manner. During short-circuit periods, the wire is fed forward and backward periodically to control short-circuit release and reduce spattering. During pulse periods, high current is applied periodically to ensure proper melting and bead formation. This periodic alternation resolves the contradiction by providing low heat input during short-circuit phases while preventing spattering through controlled periodic wire movement.
Solution Approach 2:
The patent employs dynamics by continuously adjusting wire feed speed and welding current based on the welding state. During short-circuit welding, the wire feed speed is dynamically changed to feed backward when short-circuit is detected and forward when released. The welding current is dynamically adjusted between short-circuit current and arc current. This dynamic control prevents irregular short circuits and reduces spattering while maintaining low heat input.
2Manufacturing precision
If pulse welding is used to provide stable arc and sufficient melting, then melting is improved, but burn-through occurs in thin-plate welding due to excessive heat input
Solution Approach 1:
The patent uses periodic action by alternating between pulse welding periods with high current and short-circuit welding periods with low current. During pulse periods, high current is applied periodically to ensure sufficient melting and stable arc. During short-circuit periods, the current is reduced and wire is fed backward to cool the molten pool and prevent burn-through. This periodic alternation resolves the contradiction by providing sufficient melting during pulse phases while preventing burn-through during short-circuit phases.
3Stability of the object's composition
If wire feed speed is increased to maintain stable arc during pulse welding, then arc stability is improved, but discontinuous control causes unstable welding when switching between modes
Solution Approach 1:
The patent employs dynamics by continuously and smoothly adjusting wire feed speed and welding current based on real-time welding state detection. When switching between short-circuit and pulse welding modes, the wire feed speed is dynamically adjusted to maintain appropriate values for each mode without discontinuous changes. The welding current is dynamically changed from short-circuit current to arc current with smooth transitions. This dynamic control ensures arc stability during pulse welding while maintaining overall welding stability during mode transitions.
Solution Approach 2:
The patent applies feedback by detecting the welding state (short-circuit or arc) and adjusting wire feed speed and welding current accordingly. The control system continuously monitors welding current and voltage to determine the welding state, then provides feedback control to adjust parameters. When short-circuit is detected, wire feed is adjusted; when arc is detected, welding current is adjusted. This feedback mechanism ensures stable arc during pulse welding and stable transitions between modes.
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 enables a wide range of heat input control, reducing spattering and achieving scaly beads with a beautiful wave pattern by stabilizing the arc and precisely controlling bead geometry.
Implementation Method 1
an arc is generated between a welding wire, which is a consumable electrode and a base material, which is a welding workpiece
Data Source
Figure 1(a)~1(e)
Figure 2
Figure 3(a)~3(e)
AI summary
A method of controlling arc welding with a consumable electrode includes repeating the following periods in sequence: a short-circuit welding period to perform short-circuit arc welding; a pulse welding period to perform pulse welding; and a cooling period in which the welding current output is zero.