|
MAG Welding - Welding Equipment Structure
| 1. |
Welding Equipment Structure |
|
|
|
MAG welding equipment consists of the torch, wire feeder, shielding gas supply, control unit and the welding power supply. The wire feeder and welding power supply are integrated in most modern welders.
| |
|
|
|
|
Provides a stream of shielding gas to the weld area. | |
|
|
|
Allows current to flow through the wire and generate an electric arc: |
|
|
|
? |
Attached on the end of the torch is a nozzle that guides the shielding gas to the welding area, and the contact tip, which transmits current to the welding wire. | |
|
|
? |
A multipurpose cable connect the torch to the welder. Inside is an electrical cable that carries the welding current to the contact tip, a flexible conduit liner to allow the welding wire to feed smoothly, and a passage that carries the shielding gas. | | | |
|
|
|
|
|
The wire feeder is the device that sends the wire, which acts like a welding rod, to the torch. It consists of the feed motor, reduction gear, feed roller, and press roller. | |
|
|
|
The spinning of the motor is transmitted to the feed roller via the reduction gear. The wire is then sent to the torch by pinching it between the press roller and the feed roller. The wire is provided at a desired speed based on the welder settings. | |
|
|
|
The wire is a long, single string of steel rod. The welding wire must have a tensile strength equal to, or greater than the lowest tensile strength of the parts being welded. | |
|
|
|
The wire is coated with thin copper plating to prevent corrosion and to improve conductivity with the contact tip. | | |
|
|
|
The shielding gas supply is a device that directs the shield gas from the gas cylinder to the torch. It consists of the regulator, which reduces the high pressure in the gas cylinder to the required low pressure for welding. It also allows a flow rate adjustment and has a solenoid valve starts and stop the shielding gas flow as the welder operates.
| |
|
|
|
|
The control unit receives signals from the torch switch and then: |
|
|
|
? |
Switches the welding power supply on and off | |
|
|
? |
Regulates welding wire feed | |
|
|
? |
Controls the shielding gas supply | |
|
|
|
|
The most important roles are wire feed regulation and speed control in proportion with current and voltage to maintain as constant an arc length as possible. A large number of semi-conductors are used in the power unit’s electrical circuits. | |
|
The power unit provides the electrical energy to generate an arc. It converts energy from the power supply to the desired voltage level for welding using a transformer and rectifier. | | | 
