In industrial context, welding refers to a fabrication process that joins materials such as metals and thermoplastics, by causing coalescence. This is typically done by softening the work pieces and adding a filler material, which is often a welding rod, to form a pool of molten material that cools to become a strong joint. Various processes and energy sources are used for welding, such as gas flame, electric arc, laser, electric beam, friction, and ultra sound.
Welding machines can be broadly classified into different categories depending on the type of welding processes and equipment used during the process. Some welding machines use transformers for converting high voltage, low current electricity into high current low voltage, often between 17 to 45 volts and 190 to 590 amperes. These types of welding machines are the least expensive and allow welders to select the output current by either moving the core of the transformer in and out of the magnetic field or by allowing the welder to select from a set of taps on the transformer.
Some welding machines use an internal combustion engine or an electric motor to drive the alternator or generator present in these machines. The process used is similar to transformer based welding machines as power is first converted into mechanical and back to electrical energy to achieve the step-down affect.
Inverter based welding machines use high-power semiconductors such as the IGBT for building a switching power supply capable of handling high loads of arc welding. These machines convert utility electricity into high voltage and store it in a capacitor bank. The stored energy is then transferred to a secondary transformer for producing the desired welding current.
Welding machines have simplified different types of machining jobs undertaken in small and large manufacturing companies. Automated welding machine is also in use and has helped in increasing the effectiveness of welding processes.
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