WIRE FEEDING UNIT
The wire electrodes are supplied as continues coils in wire spools. The solid wires are available in the following sizes 0.8, 1.0, 1.2, 1.6, 2.0 and 2.4 mm diameters. The wires normally would have an uniform and thin copper coating to facilitate easy current pick up. The copper coating also serves as good lubricant for the passage of the wire through the torch assembly. The consumable wire electrode is fed into the arc zone by means of the wire feed unit. The wire feed unit consist of a wire reel holder where the wire reel is mounted and a set of two or four rollers driven by a motor gear box assembly. The rollers draw out the wire from the wire reel and feed it smoothly into the torch assembly. The wire feed rate can be varied using the control knob. The roller pressure on the wire is to be suitably adjusted. The wire feed unit also contains a solenoid valve which regulates the flow of shielding gas into the torch assembly.