Dual-Wire Arc Deposition Using Bridge Droplets for Wide Weld Beads
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Solution Overview
Problem
Existing welding techniques face challenges in increasing the width or length of the weld bead without simultaneously increasing the heat input and weld bead profile, which can be undesirable for certain mechanical applications.
Innovation Solution
A dual wire configuration system where two smaller electrodes are used simultaneously, with a contact tip assembly having separate exit orifices and a specific current waveform that includes a bridging current portion and a background current portion, forming a bridge droplet between the electrodes before transferring it to the molten puddle during a short circuit event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a larger electrode diameter is used to increase weld bead width and length, then the weld puddle becomes elongated and widened, but the heat input and energy consumption increase
Solution Approach 1:
The patent divides a single large electrode into multiple smaller electrodes (typically two or more wires). Each smaller electrode contributes to forming the weld bead, and their combined effect achieves the desired weld bead width and length without requiring a single large electrode. This segmentation allows for reduced heat input while maintaining the necessary weld geometry.
2Productivity
If a larger electrode diameter is used to increase deposition rate, then more material can be deposited, but the weld bead profile becomes non-ideal for certain mechanical applications
Solution Approach 1:
Multiple smaller electrodes are used instead of a single large electrode. Each electrode deposits material that contributes to the overall weld bead, allowing for better control of the weld bead profile. The segmented approach enables ideal mechanical properties while maintaining high deposition rates through coordinated operation of multiple electrodes.
Solution Approach 2:
The patent combines the deposition action of multiple smaller electrodes to achieve the cumulative effect of a larger electrode. By synchronizing the operation of multiple electrodes, the system achieves high deposition rates similar to large electrodes while maintaining the advantageous weld bead profile characteristics of smaller electrodes.
3Duration of action of moving object
If a larger electrode diameter is used to elongate the weld puddle, then the weld and filler metals remain molten longer, but more energy is required for the welding arc
Solution Approach 1:
Multiple smaller electrodes are positioned and operated to collectively elongate the weld puddle, achieving the same effect as a single large electrode but with reduced energy consumption. The segmented electrode configuration allows for extended molten puddle duration through coordinated heating and deposition, without requiring the excessive energy input needed by a single large electrode.
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 allows for a wider weld bead with reduced heat input and an ideal weld bead profile, achieving higher deposition rates and improved weld stability without the need for larger electrodes.
Implementation Method 1
an arc generation power supply configured to output a current waveform to the first wire electrode and the second wire electrode simultaneously through the contact tip assembly
Implementation Method 2
The bridging current portion has a current level sufficient to form a bridge droplet between the first wire electrode and the second wire electrode
Data Source
AI summary
A welding or additive manufacturing system includes a contact tip assembly having first and second exit orifices. A wire feeder is configured to deliver a first and second wire electrodes through the exit orifices. An arc generation power supply is configured to output a current waveform to the wire electrodes simultaneously, through the contact tip assembly. The current waveform includes a bridging current portion, and a background current portion having a lower current level than the bridging current portion. The bridging current portion has a current level sufficient to form a bridge droplet between the wire electrodes before the bridge droplet is transferred to a molten puddle during a deposition operation. Solid portions of the wire electrodes do not contact each other during the deposition operation. The bridge droplet is transferred to the molten puddle during a short circuit event between the molten puddle and the wire electrodes.