Plasma cutter test
Plasma cutters are used for targeted and precise cutting of metal. They are portable and can cut and separate metals quickly and accurately without much effort. Plasma cutters work in a similar way to welding machines, using an arc. Unlike a welding machine, a plasma cutter does not join, but cuts (slices) metal.
What is a plasma cutter?
A plasma cutter is required in order to be able to cut metal sheets exactly to the desired size or shape in the most diverse manufacturing processes. In order to make this possible without any problems and without great effort, similar techniques to welding are used to cut through the metal sheets. An electric arc heats the metal and at the same time compressed air, alternatively a technical gas or a liquid blasted under pressure, is used to separate the surface.
How does a plasma cutter work?
For a plasma cutter to function at all, different components are required. To make the device complete, a power supply line, a ground cable, a handpiece and a compressed air supply line are connected to the power source. In comparison with a welding device, an arc is also generated in a plasma cutter, which forms between the workpiece and an electrode. Due to the hot arc, plasma gas is formed from the air mixture on the workpiece, which can reach a temperature of up to 30 000 degrees Celsius. The plasma gas is electrically conductive. A high-frequency ignition ensures the formation (ignition) of the arc. The outlet is often a copper nozzle, which is cooled with water. This constricts the arc so that it can be used specifically for cutting.
This technique can be slightly different for different manufacturers, but often reminds one of welding technology. It is not for nothing that plasma cutters are built by manufacturers who also produce high-quality welding equipment. Once the arc has been ignited on the workpiece, the torch is moved a little away from the workpiece by the force of the gas flow. Then the current increases to such an extent that the strength is sufficient to cut through the workpiece. The energy density is so high that the metal melts by the heat of the arc. The desired cut is then obtained because the resulting jet of compressed air gas separates the molten metal, creating a kerf. Only plasma cutters used for industrial purposes use inert gas mixtures that reduce or prevent oxidation on the metal surface during the cutting process. This makes the cutting process even more precise.
Possible applications of plasma cutters
Plasma cutters are used for cutting and slicing metal surfaces and sheets. Depending on the model, black sheets up to 70 millimeters thick can be cut with a plasma cutter. Sheets thinner than 70 millimeters are not a problem at all. Cutting sheet metal with a plasma cutter does not produce any shavings, and metal dust is also not visible.
Since plasma cutters perform the cuts with a maximum arc temperature of up to 30 000 degrees Celsius, the cut surfaces merge after the cut and are not sharp-edged. This effect is particularly important when a plasma cutter is used to rescue accident victims from crashed cars, aircraft wrecks or crashed trains. Further injuries caused by sharp-edged metal edges, which could occur when using rescue shears, are then not possible. In contrast to the rescue with a cutting torch, the metal is not heated as intensively (the surface conduction is missing) if a plasma cutter is used instead.
Suitable for whom?
Plasma cutters are not only required by metal processing companies for the most diverse manufacturing processes, but also by craftsmen, hobbyists and armature makers for cutting metal surfaces. These can be necessary for special productions, but also for simple repairs. In vehicle construction alone, countless sheets of sheet metal have to be welded in when vehicle parts are rusted through. To ensure that the replacement sheets have the right format, they must first be cut to size.
Because plasma cutters are portable and take up little space, they are easy to take along. More and more rescue teams are equipped with a plasma cutter when they need to rescue accident victims from cars or other metal objects. Therefore plasma cutters are of great importance in the field of first aid (fire brigade, THW, etc.). It is particularly interesting that, because of the easy to understand and simple application, both professionals and amateurs like to work with a plasma cutter.
The handling of a plasma cutter is very easy. The usual safety precautions apply, as with welding. The work surface should be non-flammable, the user’s work clothes should be appropriate and made of cotton fibres. Anyone working at such high temperatures would be reckless to wear flammable clothing made of synthetic fibres. As long as it is not an emergency operation, the metal sheet to be cut should be firmly fixed so that it does not slip when cutting with the plasma cutter. Once all preparations have been made. The plasma cutter is placed in position and assembled. Each manufacturer offers its customers a short instruction for the assembly, so that no mistakes can occur during the assembly.
The plasma cutter can be easily guided by hand. In order to make the cut exactly where it is needed, the desired cutting line should be drawn on the sheet metal beforehand. Each manufacturer specifies which tension must be set for which material thickness. The handling and operation therefore always depends on the model and equipment of the plasma cutter. Usually the earth clamp is attached to the workpiece. Before a planned use, some practice cuts should be made with a plasma cutter, so that it is known how the cutter reacts and how the cuts become most exact.
When cutting with a plasma cutter, just as with welding, slag can form on the cut. These slags are simply due to the high cutting temperatures and in no way a quality defect. They can easily be removed with a slag hammer or wire brush. The removal of the slag after cutting with a plasma cutter is of crucial importance if the cut work pieces are to be welded after cutting.
With a plasma cutter, not only can cuts be made from the outer edge of the metal sheet, but also internal circular cuts. This possibility is particularly interesting when circles or ornaments are to be cut out of a metal sheet without damaging the smooth outside of the sheet. The thicker the material to be cut, the longer the cut takes to cool down.
Modern plasma cutters work with compressed air and no longer require a special gas mixture. Some models work completely without gas because they are operated with liquid. The amount of liquid required (often water) is so small that a water tank with a filling volume of 1.5 litres is sufficient for up to a month of regular use. Technical gas is only used in precision cutting machines, which are usually only used industrially. The cutting properties are enhanced by the use of technical gas in such a way that the final result is reminiscent of laser cutting technology. The cutting surface is smooth and does not show any burr.
The performance features
Most plasma cutters work with a voltage of 230 volts, with an amperage between 50 and 300 A. With larger, stationary plasma cutters, the performance characteristics also increase. The values given refer to portable plasma cutters, which any interested party can easily buy in specialist shops.
Positive properties of plasma cutters
- Light weight and small footprintLow energy consumptionEven inexpensive models can be used reliably for hobby applicationsPlasma cutters, in contrast to other cutting techniques, can be used fairly close to the injured person during rescue operationsPlasma cutters can be constructed and repaired quickly, easily and inexpensivelyFitting sheets can be cut quickly, easily and inexpensivelyPlasma cutting can also be carried out by non-professionals, if they have some knowledge of the technology and practice
Negative properties of plasma cutters
Negative characteristics are not recognizable by the manufacturers. The only negative characteristics that can be noticed are that a buyer has not informed himself sufficiently before buying and has bought an unsuitable device.
What is tested?
With a plasma cutter, the quality of the cut is tested. The cut should be as straight as possible, not diagonal. The cut should be rounded rather than sharp. If the performance of a plasma cutter is limited and too weak for the thickness of the material used, it is possible that the metal can still be cut, but the quality of the cut suffers due to overstraining.
Therefore, before examining a cut of inferior quality, one should first check whether the device settings were correct and whether the performance of the plasma cutter was sufficient for the thickness of the workpiece.
Care and cleaning
When used carefully, a plasma cutter hardly gets dirty. It should therefore always be ensured that the device is not operated with dirty and oily hands, and that the hoses and hand parts are not stored in dirty areas. Simple cleaning with a dry, soft cloth after use should therefore always be sufficient. The appropriate wearing parts are available from specialist dealers and can be replaced without hesitation if the unit does not have to be laboriously dismantled for replacement.
How much does a plasma cutter cost?
The cheapest plasma cutters are available in stores for around 350 euros. There is hardly any limit to the price when plasma cutters are custom-made for special cutting jobs in the industrial sector. Concerning the price it is worth mentioning that the cheap devices are suitable for the hobby sector, if it is to become more professional, you have to get deeper into your pocket.
Who repairs plasma cutters?
Plasma cutters, like welding equipment, should never be repaired by yourself. The risk of equipment damage, which could ultimately lead to physical injury, is far too great. Most manufacturers have service points that are spread all over the country. Otherwise, defective equipment can be sent in. Especially in the case of damage during the warranty period, you should always refrain from carrying out repairs yourself, even if you have the necessary expertise, because then the warranty will expire.
What can a plasma cutter do?
A plasma cutter can make hand-guided cuts in metal sheets. These cuts can be individually guided on portable devices. If the material cuts in metal sheets are to be used industrially, and therefore need to be guided particularly precisely, special CNC plasma cutters can be used. These are computer-controlled and work absolutely accurately.
The 5 major manufacturers and their respective characteristics
- REHM customer service, the company offers not only high-quality plasma cutters, but also sophisticated welding technology. Several service locations guarantee customers the best support.CNC-STEP e.K., the company has its headquarters in Germany in Geldern and offers plasma cutters for professional use.Lorch Schweißtechnik GmbH, headquarters in Auenwald/Germany The company offers plasma cutters and welding technology.FRONIUS DEUTSCHLAND GMBH, the company has its German headquarters in Kaiserslautern and offers not only plasma cutters but also high-quality welding technology.Cebotech GmbH, the company is located in Sinsheim/Hilsbach and offers not only plasma
What accessories are available?
In addition to the basic equipment, which is complete when buying a plasma cutter, longer hose connections, clamps, protective clothing can be added. As the arc is very bright when using a plasma cutter, wearing protective goggles is recommended in any case. This not only protects the eyes against the brightness, but also makes it easier to check the cut. With some plasma cutters, different cutting nozzles can be purchased, which can be operated with different amperages, depending on the desired material thickness. Trolleys facilitate the portable use of a plasma cutter.
What to look out for when buying?
The plasma cutters available on the market are designed for different applications. Although the devices can be used variably because they can be individually adjusted to the workpiece, they have a maximum upper limit that cannot be exceeded. It is therefore important that the desired cutting depth does not exceed the maximum material thickness a plasma cutter can cut. Before purchasing, it should therefore be determined for which work the device is required and what maximum performance it must provide. This is the only way to avoid a bad purchase.
5 good reasons for plasma cutters
- Plasma cutters work exactly, without a large heat distribution in the surface areas next to the planned cuts.plasma cutters are transportable and can therefore also be used on the road, for rescue services or on construction sites.the energy requirement is rather low, therefore the transportable use of plasma cutters is also possible with the help of a household power supply.the exact cutting pattern of a plasma cutter is not comparable with the cutting pattern of a sheet metal shears or a cutting torch.the technology of a plasma cutter is mature and, when used correctly, quite safe.