A plasma cutter is a complex piece of equipment that has many features, and so choosing the one that is best for your needs is not a simple process. However, it is important that you take all relevant factors into account and choose carefully because the right plasma cutter can make tremendous improvements to your business.
A properly selected plasma cutter will be high quality, affordable and able to cut a range of materials of different thicknesses quickly and accurately. It will be easy to operate, dependable and won’t be over-costly in its use of consumables and maintenance. It will provide excellent throughput, improving your company’s productivity and profitability. But it will only do all that if you make the right choice.
How to Choose the Right Plasma Cutter
Before starting the process of assessing the most suitable plasma cutter, you should first assess your needs. Determine the type and size of material you want to cut, and how, where and how often you will do it.
Identify your workshops power availability and available space, and the budget you have to pay for the equipment. Once you have done that, you can make a more informed assessment.
How Big a Plasma Cutter Do I Need?
A plasma cutter is capable of cutting large and thick pieces of conductive material, but the exact capacity will depend on the size and specification of the machine you choose. Beyond maximum cutting thickness, cutting speed can also be a key factor — especially in a production line environment where high, uninterrupted throughput is essential.
Many plasma cutters are rated by their cutting capacity. For example, a machine rated for 25 mm can melt and cut through steel of that thickness. They may also be rated on cutting speed, expressed in millimetres per minute for each metal thickness.
If high throughput is critical, it’s often wise to choose a machine with double the capacity you expect to use — for instance, using a 12 mm-rated machine when you regularly cut 6 mm plate — to ensure faster speeds and a cleaner cut. While a smaller machine may technically cut thicker material, the quality may suffer, leaving behind dross and slag that require extra clean-up.
Cutting speed is also influenced by the machine’s duty cycle — the percentage of a 10-minute period it can operate before needing to cool down. A high duty cycle is essential for long or deep cuts, while a lower duty cycle may be adequate for smaller, intermittent work. Pushing a machine beyond its duty cycle can lead to overheating, unnecessary wear, and higher maintenance costs.
How Many Amps is a Good Plasma Cutter?
The thickness of metal a plasma cutter can handle is directly linked to its power output, which is determined by the machine’s amperage and power supply. In general, the higher the amp rating, the thicker the material it can cut efficiently, while lower amperage limits the machine to thinner metals.
As a guide:
- Around 25 amps will comfortably cut up to 6 mm mild steel.
- 50–60 amps will handle up to 12 mm.
- 100–125 amps can cut up to 25 mm.
- 200 amps will handle plate up to 40 mm.
- 300 amps will cut up to 50 mm.
- At the top end, a 460 amp industrial system can pierce 64 mm mild steel straight out of the box.
When choosing a machine, it’s best to match it to the material thickness you cut most often — but if production speed and cut quality are priorities, select a machine with more capacity than your day-to-day requirements. For example, using a 25 mm-capable system for regular 12 mm work ensures faster throughput, cleaner edges, and minimal post-cut finishing.
An undersized system may still sever thicker plate, but the cut will be slower, rougher, and likely require significant clean-up before use.
What is the Recommended CFM for a Plasma Cutter?
CFM (cubic feet per minute) and SCFM (standard cubic feet per minute) are measures of gas flow rate from an air compressor, with SCFM referring to the rate under standardised operating conditions. In Australia and New Zealand, flow rates are often expressed in litres per second (L/s) or litres per minute (L/min), although some manufacturers still quote CFM/SCFM.
Every compressor has a motor and a storage tank that supplies gas to the plasma cutter. This gas is pressurised and heated to extremely high temperatures, creating the plasma arc that melts and blows away metal for a clean cut.
Portable systems generally have smaller storage tanks and may include a built-in compressor, while fixed industrial systems use larger external compressors for greater capacity and consistent performance.
The actual flow rate a compressor can achieve depends on the tank size and its output pressure. In Australia/NZ, pressure is measured in kilopascals (kPa), bar, or megapascals (MPa). Typical cutting systems operate with:
- Smaller, hand-held cutters (20–30 amps) requiring around 550 kPa (5.5 bar) inlet pressure.
- Larger, automated CNC plasma cutting machines (130–800 amps) needing 800 kPa (8 bar) or more.
Most industrial compressors can deliver these pressures, but remember the inlet pressure at the plasma system will usually be lower than the compressor’s rated output due to line losses, fittings, and filters. To compensate, set the compressor output slightly above the plasma system’s required inlet pressure.
As a rule of thumb, your compressor’s flow rate should be at least 150% of the plasma cutter’s gas consumption rate. Ensure the air line or hose is rated for the system pressure, is wide enough to handle the required flow, is corrosion-resistant, and is protected from moisture build-up. Depending on the system, typical air consumption ranges from 100 to 190 L/min for smaller cutters up to 400+ L/min for large industrial systems.
How Usable is the System?
A plasma cutter is a complex piece of equipment, but it can be relatively simple to operate with the right user interface. A control panel that is large and easy to read will help, while information printed on the unit itself can make starting and setting up fairly straightforward.
Being able to use a machine in advance of purchase will enable you to test its functionality and ease of use. Make test cuts with different types and thicknesses of materials, checking the speed, accuracy and quality of the cuts. A plasma cutter with a tight and focused arc will better concentrate the cutting power on the material and give the best results.
As the torch is brought near to the material to be cut, it transfers from a pilot arc to a cutting arc. You ideally want a system that handles this transfer quickly while still being some distance from the material because this will give a more satisfactory output. For some plasma cutters, the pilot arc uses high frequency to conduct electricity, and this can interfere with other equipment. If this is a potential problem, choose a cutter with an alternative starting method, such as back arc.
Check that you can see what is being cut while the torch is operational. Good visibility is usually enabled by a torch that is compact or has an extended nozzle.
If you need a portable rather than a static unit, check that it’s easy to move around and is small enough to fit in the required areas. It should also have its own compressor and built-in storage for the torch, cable and consumables to make transfer easier.
Lastly, but most importantly, ensure the system has adequate safety features. These should include warnings before the system starts and the prevention of starting if the nozzle is not in place.
What are the Operating Costs?
Apart from electricity and gas costs, the biggest costs associated with operating a plasma cutter are for the replacement of consumable parts. These parts include electrodes and cutting tips that will wear out with use.
A damaged or worn cutting tip will either result in lower quality cuts or the process taking much longer than previously. Either of these will reduce productivity and profitability, so you must check and replace all consumable parts as necessary.
A system with fewer consumables will generally be cheaper than one that has a lot of them. For those that are present, check the expected life and cost of the consumables, and compare the data for different systems. The difficulty may be obtaining comparable data since some manufacturers quote consumable life in terms of the number of cuts, while others quote the number of starts.
Durability is also a big factor because these systems are often worked hard in harsh environments. Check the ruggedness of the system and if fittings, torch connections and particularly filters are protected. Dirt and moisture in the gas will reduce cutting performance, so protection of the filters is essential.
All the Help You Need
Choosing a plasma cutter is not a simple process because you need to consider and compare many factors. We are here to make the process as easy and stress-free as possible by supplying all the help and advice you need.
Contact us today and we’ll make sure you get the plasma cutter that’s right for your business.