MMA process use drooping characteristic power source and consumable electrodes which produces arc by scratching the electrode with the job forming a short circuit. It is only when the short circuit is broken, arc is formed and the main welding current starts flowing. Welding takes place as the electrode gets fused with the job under the cover of the slag. In case of TIG, arc starts between tungsten electrode (non-consumable) and the job under the cover of inert gas. Arc is started by scratching the tungsten electrode with the job or using a high frequency unit which initiates the arc between the tungsten electrode and the job.

• SAPPHIRE Series MMA/TIG Welding Machines
Diode based power sources are the basic type arc welding power source used for MMA/TIG applications. Current control is achieved through saturable core reactor. Very reliable power source but not recommended for radiographic welding application as there is no dependable feedback for maintaining the output current constant due to fluctuation of input supply or change in load. Power factor is poor for these power sources.

• TD Series MMA/TIG Welding Machines
Thyristorised power sources have current feedback control which maintains the set output current constant. There can be many welding features such as up slope, down slope, pulsing, etc. which can be incorporated in this type of power source. Efficiency and power factor of these machines are better than diode based machines.

• SOLARIS Series MMA/TIG Welding Machines
Inverterised Welding machines are manufactured using switching devices such as IGBT (Insulated Gate Bipolar Transistor) MOSFET etc. This makes the power source very compact in size, very efficient and best in power factor. These power sources are incorporated with digital technology such as DSP etc. Fully programmable machines are available under this category.

• AC DC TIG Series MMA/TIG Welding Machines
A power source which can be used as Alternating OR Direct current power source with high frequency and programmable welding features. AC TIG is used for Aluminium Welding. Thyristorised or inverterised power sources are available with AC/DC characteristics. Welding transformers (AC) with DC suppressor, High frequency unit and TIG torch is used as AC TIG welding machine for Aluminium Welding applications. But this cannot weld precision jobs.

• MINIWELD Series MMA/TIG Welding Machines

Gas Metal Arc Welding (GMAW), sometimes referred to by its subtypes Metal Inert Gas (MIG) Welding or Metal Active Gas(MAG) Welding, is a Welding process in which an electric arc is formed between a consumable wire electrode and the work piece metal, which heats the work piece metal, causing them to melt and join. Along with the wire electrode, a shielding gas is fed through the welding gun, which shields the process from the contaminants in the air. The process can be semi-automatic or automatic. A constant voltage, direct current, power source is most commonly used with GMAW, but constant current systems as well as alternating current can be used. There are four primary methods of metal transfer in GMAW, called globular, short circuiting, spray and pulsed spray each of which has distinct properties and corresponding advantages and limitations. It is a faster and economical welding process. Almost all metals can be welded with this process Argon, Argon+CO2 or only CO2 is used as shielding gas depending upon the metals to be welded. Inert gas(Argon) is used for Aluminium, SS etc. Active Gas CO2 or mixture of Argon+ CO2 is used for mild steel welding. Sometimes flexed cored wires are used.

Diode based MIG/MAG (CO2) Welding machine
These are constant voltage power sources. Output voltage is selected in steps. The selected voltage remains almost constant but fluctuates with the fluctuation of input supply voltage. There is no feedback control to maintain the voltage constant. Wire feeder is used for consumable electrode feeding. Spool of wire is mounted on the wire feeder which has two or four roll mechanism driven by a DC permanent magnet motor or Print motor with servo control which ensures constant feeding of wire. Electrode and shielding gas are fed through the torch. Gas flow rate is controlled manually using flow meter and regulator. CO2 gas is hygroscopic in nature hence absorbs moisture as soon as released from the pressurized cylinder. A preheater is used in the gas supply line soon after the cylinder for heating the gas as moist gas spoils the weld quality.

Thyristorised MIG/MAG (CO2) Welding machine
Thyristorised MIG/MAG (CO2) Welding power sources are generally constant voltage power source but sometimes constant current characteristics are also provided as an option. This has feedback control for maintaining set voltage (or current in case of constant current option) constant. The output voltage can be set steplessly. Such power sources are also available with programmable features and synergic options. Wire feeder, welding torch, gas flow meter and regulator, gas preheater are essential accessories for welding. This type of power source produce more reliable quality of welding compared to diode based power supply.

Inverter based MIG/MAG Welding Machine
Inverterised MIG/MAG power sources are designed for constant voltage or combination of constant voltage/constant current characteristics. The weld quality, efficiency and overall productivity with this type of power source are maximum. The spattering is negligible. It is possible to achieve weld quality as close to TIG process for pipe welding applications. The output characteristics of the power source and wire feeding may be programmed to achieve desired welding parameters for superior weld quality. It is more convenient to integrate such power sources for automation applications. Wire feeder, welding torch, gas flow meter and regulator, gas preheater are essential accessories for welding.

Submerged Arc Welding (SAW) is a common arc Welding process. It requires a continuously fed consumable solid or tubular (flux cored) electrode. Molten weld and the arc zone are protected from atmospheric contamination by being “submerged” under a blanket of granular fusible flux consisting of lime, silica, manganese oxide, calcium fluoride and other compounds. When molten, the flux becomes conductive and provides a current path between electrode and the job. The thick layer of flux completely covers the molten metal thus preventing spatter and sparks as well as suppressing the intense ultraviolet radiation and fumes that are a part of the SMAW process.

SAW is normally operated in the automatic or mechanized mode, however, semi-automatic (hand held) SAW guns with pressurized or gravity flux feed delivery are available. The process is normally limited to flat or horizontal fillet welding positions. Deposition rates approaching 45kg/hour is possible with this process. This requires constant voltage power source.

Diode based SAW power source
Diode based SAW power source has output voltage controllable in steps with no feedback control for voltage or current. Motorized trolley for voltage or current. Motorized trolley is used for carrying the welding head with wire feeder, wire spool and the flux hopper. Displays for welding voltage, current, wire feed speed and the trolley speed are available. These power sources are rated for continuous duty and welds for hours together without stopping.

Thyristorised SAW power sources
Thyristorised power source has feedback control for voltage. This also has feature which limits the current to designed level as protection. This type of power source allows step less control of output voltage and maintains the set voltage constant.

Inverterised SAW power source
Inverterised SAW power source is incorporated with constant voltage/constant current characteristics. They allow step less selection of output voltage. The weld quality is superior with this type of power source.

Features:

• Provides smooth, stable and precise oscillating movement of the welding torch.
• Increases sidewall fusion, eliminates undercut.
• Improves weld quality and appearance .
• Independent dwell settings and speed settings for each side.
• Compatible with PTA, GTAW, PAW, GMAW, FCAW and SAW weld processes.