Lincoln Electric IM666-A manual General Description, Design Summary

A-2 INSTALLATION A-2

GENERAL DESCRIPTION

The Tandem MIG torch delivers two wire electrodes to the weld pool. The wires are insulated from each other for the purpose of independent arc regulation. When welding, the wires or arcs are oriented one behind the other. The torch provides a small but rugged housing for delivering the two wires and it provides secure delivery of the shielding gas. Each side of the torch is rated for 450 Amps, 100% duty cycle with argon mix shielding gases.

The 900 amp Tandem MIG torches are supplied in two different configurations, the G3494-2 thru -6, (sin- gle gas delivery configuration) and the G3494-2A thru -6A (dual gas delivery configuration). The G3494-2 thru -6 is configured to be used with .035"-.052" diam- eter electrodes. Shielding gas delivery is by a single gas hose that delivers gas to the torch body. Internal to the torch body the gas is split and delivered to the two gas diffusers.

The G3494-2A thru -6A model is configured for .035"- 5/64" diameter wires. The G3494-2A thru -6A design provides larger volumes of gas for gas shielding of the welding arcs and weld pool. Gas is delivered through the two welding power cable assemblies of the G3494-2A thru -6A; each assembly receives separate shielding gas from the two separate wire feeder sole- noids. The dual source of gas provides additional gas volume needed for proper gas shielding of larger weld pools.

The torch can be operated bi-directionally, or even as a single wire torch as the need arises.

The Tandem MIG torch is not factory equipped with a feeder end connector. Use a K489-7 Fast-Mate adapter kit (see ACCESSORIES section) to attach the torch to the feeders. A K1500-1 gun connector must be installed in addition to the K489-7 Fast-Mate adapter, when using a Power Feed 10R Wire Feeder.

Liners are not included with the torch and must be ordered separately (see ACCESSORIES section).

The torch is suitable for welding with Lincoln solid wire steel MIG wires and metal core electrodes, from .035" to 5/64" (0.9 mm to 1.9 mm) diameter.

Argon based shielding gases are recommended. 100% CO2 is not recommend because of the higher spatter levels associated with the gas.

DESIGN SUMMARY

The case, internal components and cables are the main sub-assemblies of the torch.

TORCH CASE

The case is made from several pieces fabricated from aluminum. The aluminum parts offer rigidity, strength and resistance to heat and spatter. The main housing is drilled and tapped for easy mounting to fixturing equipment. For automation and robotic applications, the barrel of the torch is removable and replaceable without having an effect upon the existing tool center point.

INTERNAL ASSEMBLY

Figure 1 Internal Assembly

All of the internal components are over molded with a high temperature epoxy material. The over molding rigidly holds all the parts in place while simultaneously insulating the sub-assemblies. Each "subgun" in the torch is electrically isolated from all other components and individually water cooled. Separate water cooling circuits minimize corrosion from electrical or galvanic action.

Each face on the subguns where the diffuser engages the torch is milled at a precise angle. The angle helps to keep the ends of the wires close together while allowing the use of standard contact tips. The slight bend also creates good electrical contact between the wire electrode and the tip.

TANDEM MIG TORCH