Synergistic-Controlled Pulsed MIG (GMAW-P) Welding Method

Introduction

Today, the most common method for joining metals by welding is the MIG welding technique, which is performed using a consumable electrode under an atmosphere of shielding gas or a gas mixture. MIG gas-shielded welding with a consumable electrode has a wide range of applications. The MIG welding method offers numerous advantages, including mechanizability, high welding speed, the ability to use robots, ease of application in complex welded structures, and the ability to weld commercial metals such as carbon steel, stainless steel, aluminum, and copper. For this reason, the market share of this method is steadily increasing. Although MIG welding is suitable for aluminum and its alloys of any thickness, it is generally preferred for welding aluminum and its alloys thicker than 3 millimeters. This is because the welding speed and melting power in MIG welding are higher than in TIG welding; consequently, very thin sheets can only be welded using the pulsed current method.

Synergistic Controlled Pulsed Welding Method

The use of the MIG (GMAW) method is rapidly increasing in many manufacturing industries. Its suitability for automation and robotic production is encouraging many researchers to study the details of GMAW welding. However, GMAW processes have certain limitations in terms of metal transfer. Melting defects that occur can negatively affect weld quality. The synergistic controlled pulsed current technology developed in recent years helps overcome these limitations in weld quality. In the pulsed MIG (GMAW-P) process, a droplet of molten metal forms at the electrode tip with each pulse. When sufficient current is applied, this droplet is forced into the weld pool. Pulsed GMAW enables higher-quality welding of thin parts, distortion control, and the ability to operate at low wire feed speeds.

Synergic control simplifies the selection of parameters such as base metal, electrode diameter, and shielding gas type. In synergic-controlled pulsed MIG welding machines, welding parameters such as voltage, wire speed (current), material type, wire diameter, and shielding gas are pre-programmed. Additionally, these machines emit warning signals in cases of overheating, power supply failure, or wire feed errors. As wire speed increases, current intensity also increases and arc length shortens; when wire speed decreases, current intensity drops and arc length lengthens. In these systems, arc length is balanced based on the relationship between wire feed rate and current intensity. In the design of these machines, programs are developed by taking into account all welding parameters and potential issues to achieve a smooth and stable arc. Based on these programs, tables are created to achieve the best weld bead.

Light Metals and the Pulsed MIG Welding Method

For welding light metals, alloys, and metal-matrix composites, a welding method that reduces heat input is required. For this reason, pulsed MIG welding methods—such as laser, electron beam, diffusion-type, friction stir, and fusion-type—which have high energy density, have been developed. Fusion-type pulsed MIG welding is the most ideal and economical of these methods. The advantages of this method include continuous wire feeding, slag-free welding, no need for skilled operators, easy automation, and the ability to weld in any position.

MIG welding operates with globular metal transfer at low currents, while at high currents the process switches to spray mode. However, the droplets formed in this mode can cause significant heat transfer to the workpiece and result in a wide weld bead. The pulsed current method is a current technique that overcomes these disadvantages. Pulsed MIG is a contactless metal transfer method between the electrode and the weld pool. A droplet of molten metal forms at the electrode tip with each pulse, and the transfer of these droplets occurs at a rate of one droplet per pulse.

Result

Pulsed MIG transfers molten droplets from the electrode to the weld pool at two different speeds, depending on the peak and fundamental current intensities. The synergistically controlled pulsed MIG welding method offers numerous advantages over the conventional MIG method while improving weld quality by reducing heat input. In summary, this method enables the successful and efficient welding of light metals, alloys, and metal matrix composites. However, further scientific research is needed in this area, as new programs must be developed to achieve efficient welding using the synergistic controlled pulsed MIG welding method.