How does a welding machine work?
A basic distinction is made between two types of welding processes. One is fusion welding (without force) and the other is pressure welding (with force). In fusion welding, workpieces with mostly similar metals are melted at the joints.
These are then combined without or with the addition of additives. The energy required for this is supplied from outside. The most common fusion welding processes are gas shielded arc welding and electrofusion welding. Here, occupational health and safety is always important. Here could be
- UV raysHeatBright arc or spark
endanger health. For your own safety, you should wear strong clothing and leather gloves when welding. Leather aprons also offer additional protection.
Basics of electrofusion welding
One electrode serves as the anode (positive pole) in electrofusion welding. The workpiece serves as the cathode (negative pole). A pole is connected to a bare part of the workpiece with a clamp. The other pole is connected to the electrode holder with which the end of the electrode is guided to the relevant welding point. This leads to a short circuit and the result is an arc. With the arc, the bundled energy generates high temperatures.
What is required for electrofusion welding?
A welding machine is needed for electric welding, which converts the alternating current of the mains into an alternating current with a low voltage and high current intensity. Inverters or welding transformers are available for this purpose.
The metal rods with a coating serve as welding electrodes during welding. This coating of the electrode has a special task during welding. During the welding process gases are formed. These stabilize the arc, prevent oxidation of the weld seam and counteract a bubble effect. Furthermore, a slag is formed which reduces the stress on the material surface. It also binds impurities and supports uniform cooling.
Gas shielded arc welding is another fusion welding process (metal active gas welding, MAG welding). A high deposition rate is achieved by means of a visible, concentrated arc. Gases are also used to protect the seam, the joints and the arc from ambient air. For this reason this process is also called gas-shielded welding. Mixtures of carbon dioxide and argon are used as a gas, for example. This type of welding is very versatile. Both a strong material and thin sheets from about 0.5 millimetres upwards can be used.
A mains and gas connection is required for the MAG welding unit. The gas with the wire electrode is fed to the torch through a hose package. The attached nozzle ensures an even gas flow. A switch on the gun starts the gas supply and the electrode supply. The torch is then supplied with the current provided by the welding machine. This current then also reaches the earth electrode. The current melts the welding wire drop by drop and thus reaches the welding point.