In metallurgy, there are several cutting techniques. Some exist only in pure theory. What is tangible, however, is the revolution that the plasma cutter has brought to the daily work of metallurgists, body shop technicians, boilermakers, etc. The device allows operations to be carried out with great flexibility as well as with millimeter-level precision, making the cutting of certain metals less arduous. Aluminum, steel, brass, copper — nothing is out of reach. How? The key lies in the composition of plasma, a material capable of reaching incredible temperatures in record time.
Just like a welding machine or any other device that is part of a welder's toolkit, the smallest accessories also matter for a plasma cutter. Torch, plasma cutter, nozzle… dive into the heart of this technology and discover its field of application through its various accessories.
Plasma and plasma cutter: what are they?
The first idea that comes to mind when you hear about plasma is undoubtedly blood plasma. However, that is not the case in our context. Here it refers to an ionized conductive gas. Ionized because plasma is a gas in which free electrons can move without needing to be bound to atoms. The gas is therefore air transformed into plasma, which has become conductive and fuses at enormous temperatures in order to remove the metal.
The plasma cutter is therefore a device that concentrates the power of plasma in order to cut sheet metal with a thickness ranging from 2 to 44 mm. It also incorporates an inverter whose role is to convert alternating current into direct current. The inverter conditions the plasma so as to generate the electric arc, enabling its ionization to produce heat equivalent to 18,000°C.
Thus, the plasma cutter is primarily the combination of an auxiliary compressor used to produce air, a plasma torch, and a ground clamp that will be attached to the element to be cut.
What are the different components of a plasma cutter?
To cut metal with such efficiency, the plasma cutter can rely on a set of essential elements:
- The inverter: for all professional accessories carrying high-intensity current, an inverter is a necessity. It can be with or without compression, but must unquestionably operate on direct current (between 230 and 400 V);
- The plasma torch: it is in a sense the centerpiece of the whole assembly since it conducts the plasma. It comes with a cable and a hose (3 to 4 meters) to give you a certain freedom of movement;
- Guidance accessories: their function is essentially to help the device achieve better precision;
- The ground cable: it simply serves to connect the clamp to the ground;
- The inverter: this is the plasma cutter component featuring a particularly interesting technology. It gives the device the quality of intelligent equipment. This is explained by the fact that, thanks to the inverter, it is possible to combine electronics with welding or cutting methods.
How does a plasma cutter work?
The operating principle of a plasma cutter is quite simple. First, you will need to switch on the device via a switch. Then take the ground clamp and place it on the sheet metal to be cut. Place the plasma torch on the part to be cut, then press the trigger which, thanks to the high frequency, will initiate remote ignition so that the metal can enter fusion. Make sure, however, that the plasma cutter torch is at the appropriate distance so that the result is clean and consistent.
Furthermore, if you do not have a steady hand, there are accessories specially designed to allow you to use the plasma cutter torch with great precision. You will be able to find from your supplier a compass that will help you with disc cutting, a standoff guide that can be adjusted closer or farther depending on the application. You can also use a straightedge guide as well as many other plasma cutter accessories.
What is the purpose of a plasma cutter in welding?
Just like a Mig or TIG welding machine, the plasma cutter is a device prized in industrial construction. We will focus particularly on the welding context since that is where it is most commonly used. It is primarily used to dismantle or cut conductive metals (aluminum, copper, brass…). The distinctive feature of the plasma cutter lies in its speed and precision. Plasma allows the cutter to operate with twice the speed and precision of a laser, regardless of the surface. Beyond this, the plasma cutter is not only efficient but also less energy-intensive.
Important accessories for a plasma cutter
These small adaptable components are the main subject of this article. Above, we listed the main components of a plasma cutter: a compressor, a torch, and a ground clamp. It would also be worthwhile to elaborate on the various elements that make up the cutter head.
The plasma torch
This is, without question, the most important plasma cutter accessory in the entire device. It conducts the plasma and alone comprises at least 4 other elements essential to its operation.
The diffuser
Its role is to ensure perfect air regulation as well as a uniform flow rate. Remember to replace it whenever its holes become clogged. This will ensure the longevity of the device.
The nozzle
Since plasma can reach incredible temperatures and the plasma cutter torch is the element in contact with it, it is entirely normal for this plasma cutter consumable to have a cooling system. The nozzle is therefore the plasma cutter accessory that regulates the cooling air of the torch. If it becomes deformed due to projected metals, you must replace it immediately.
The nozzle
This is a plasma cutter consumable made of pure leather that serves to confine the produced plasma toward the diffuser. Furthermore, it is very sensitive to impacts.
The skid
The skid is an object that welders use to maintain the gap between the sheet metal and the nozzle. However, once experience and dexterity are acquired, some welders prefer to do without this accessory.
The emissive electrode
Heavily used, the emissive electrode is a tip-shaped accessory. It is essential to the operation of the cutter head.
How to choose a plasma cutter and which one to choose?
The first recommendation we can make is to choose your cutter based on the project you wish to carry out. Once the criteria related to the project have been determined, you will be able to more easily identify the plasma cutter that suits your needs. One of the most decisive criteria is your budget. Based on it, you will determine which type of plasma cutter to buy. However, if your budget is limited, you can still afford a cutter. There are portable, compact models that are just as effective.
For your first purchase, we unreservedly recommend the portable plasma cutter with integrated compressor. Everything is designed to allow you to get familiar with the tool very quickly. Its weight, size, characteristics, and compact design will allow even beginners to cut sheet metal or profiles with great precision.
Precautions and usage tips
For a clean and proper cut, it is essential that the welder's visibility is unobstructed. Furthermore, the operation generates ultraviolet rays that impair good visibility of the cutting area. It is advisable to start by equipping yourself with a welding mask. The rest of the equipment is that conventionally used by a welder for any other welding operation: soft gloves and a leather apron to protect yourself from metal spatter. Also remember to wear gaiters to protect your safety shoes.
The plasma cutter generally operates with air, but the latter can be replaced by nitrogen. If you use nitrogen, make sure to adequately ventilate your workstation. There are options and features to best ensure your safety. The first we suggest is thermostatic protection. This is a measure that shuts down the device when it overheats or when an electrical incident occurs due to a voltage imbalance (overvoltage/undervoltage).
The second measure emits a signal when the voltage within the plasma torch begins to increase. This signal lets the welder know when to begin cutting. The last measure concerns High Frequency (HF) ignition of the pilot arc. This option makes it possible to determine the appropriate setting to start cutting without the nozzle and the metal being worked coming into contact.