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What is plasma cutting?

Welding is probably the fastest, most efficient way to join metals. Similarly, plasma cutting (or plasma arc cutting) is one of the quickest, most efficient, most accessible ways to cut diverse metal types and thicknesses.

Invented in the mid-1950s, plasma cutting evolved directly from the TIG welding that was developed in North American aerospace a decade earlier. With increasing use of aluminium, magnesium and other non-ferrous alloys, plasma cutting met the need to cut metals that couldn’t be cut easily with traditional oxy-acetylene torches.

Gas is ionised to become plasma

Plasma cutting works by projecting a high-pressure jet of superheated gas through a constricted opening, a nozzle tip (typically 0.9–1.5 mm diameter) set within a shielding cup.

As the high-pressure gas passes a negatively charged electrode inside the nozzle, the high temperature, typically around 30,000 ° F (16,648° C), ionises the gas to create what’s known as plasma. The plasma stream is projected with great precision onto the (positive) workpiece. As you can imagine, it is much more focused and precise than traditional oxyfuel cutters.

Reliable plasma cutters are now affordable

Because plasma can cut through even thick metals with ease, the technology has found widespread adoption in workshops and factories around the world. Now that high-quality plasma cutting machines are so affordable, amateur metalworkers have access to technology once restricted to professionals.

Read The R-tech Welding Equipment Guide to Plasma Cutting here…

How plasma cutting works

The narrow jet of plasma is focused by the nozzle tip of a plasma torch. This gives a very precise, ultra-high temperature cutting flame. The flow of plasma conducts electricity from the torch to the workpiece. In turn, this heats your workpiece and blows away the molten metal. The result is a precise, slag-free cut with minimal kerf.

As you can see from the plasma cutters on our website, modern machines are remarkably compact. For example, our advanced I-Cut100 plasma cutter measures only 515 x 220 x395 mm.

That box contains all the advanced electrical components and an air-valve assembly. A hand-held plasma cutting torch, and an earth lead and clamp, attach to the cabinet in the same way that welding machine accessories attach.

Suited to a wide range of non-ferrous metals

Because plasma cutting works best with conductive metals, it is perfect for cutting non-ferrous metals such as these:

  • Aluminium
  • Magnesium
  • Stainless steel
  • Copper
  • Brass
  • Mild steel
  • Cast iron

Pros and cons of plasma cutting

Like any industrial process, plasma cutting comes with its advantages and disadvantages. Here are the main ones:

Advantages of plasma cutting

  • Cylinder gas may not be required – although gases such as oxygen, high-purity air, nitrogen and specialised hydrogen/nitrogen/argon mixtures can be used for special types of plasma cutting, basic cutting can be done with standard compressed air.
  • As you can see from the list above, plasma cutting is suitable for a wide range of metals and thicknesses. Most non-ferrous (iron-free) metals are suitable.
  • Speed – on metals less than ½ inch (12.5mm) thick, plasma cutting is typically four-times faster than oxyfuel cutting. Watching a plasma cutter at work really is like watching that proverbial hot knife through butter.
  • Plasma cuts with minimal risk of the distortion that can occur with traditional oxyfuel cutting.
  • Plasma cutting is renowned for precise, clean cuts with narrow kerf and no slag.
  • Plasma cutting works flat, vertically or horizontally (but remember that for safety reasons, plasma cutting at more than 100 A should only be done flat).
  • For some materials (in particular, thick steel) plasma cutting is slower and uses more energy than other methods.
  • Most plasma cuts will have a slight bevel (around 6–7 degrees). This is caused by the motion of the plasma gas as it emerges from the torch nozzle and is unavoidable. Other factors influencing bevelling include the type of cut and worn consumables (such as torch tips).
  • You need to be close to a source of electricity; plasma cutting doesn’t come with the traditional portability of oxyfuel cutting.
  • Plasma cutting comes with serious risks of electrical shock.

Disadvantages of plasma cutting

As you can see, plasma cutting has some disadvantages, but compared with its plus points, we’re sure you’ll agree that these are a minor consideration compared to the plasma cutting’s considerable strengths.

R-Tech Pro Tip – Daz at R-tech reminds us that for with plasma cutting, you will usually achieve the best bevel with what’s called a ‘climbing’ cut.…

Plasma cutting equipment – the R-Tech way

We built our service for metalworking professionals and amateurs on supplying reliable, high-quality equipment. All our plasma cutters are easy to use and proven in the most demanding professional and amateur environments. With quality and reliability comes exceptional value too – just read our customers’ reviews.

Then there’s the reassurance of our direct customer support. It begins with your first enquiry or information request and continues as you choose and use your plasma cutter and accessories.

Forget the inconvenience and delays of going through distributors who don’t make and service plasma cutters themselves. With R-Tech you deal directly with the manufacturer.

Built to last

All our plasma cutters are robustly built. And they all use the latest ultra-reliable components from American and German companies. These include class-leading Siemens IGBTs rather than inferior MOSFET electronics.

To keep whole-life ownership costs as low as possible for you, we design and build our plasma cutters on a modular basis – just as we do for our MIG and TIG welders. That means they can be maintained and repaired at component level.

Trusted back-up and support

Finally, we back every R-Tech plasma cutter with a no-quibble three-year ‘collect and return’ warranty and a reassuring 10-year duty of care. It all adds up to minimising long-term running costs of your R-Tech plasma cutter – while you get on with metal working.

By the way, if your plasma cutter ever needs to visit our – exceptionally quiet – repair department, we’ll lend you another plasma cutter free-of-charge so you can keep making money or enjoying your hobby.

‘Just received my P30C Plasma Cutter well packed and next day delivery excellent service will be testing it out at the weekend on some 5mm plate steel another fire pit to make!just tried out plasma clean cuts 5mm steel with ease this is a very good machine many thanks rtech’

– Kevin Parry on Google Reviews

We’re here to help

Whether you’re a novice or working for a giant engineering company, we’re here to help with all aspects of plasma cutting and plasma cutters. Our acclaimed support begins the moment you send us an email or call us. Let’s talk plasma cutting!

Email us now or call 01452 733933 for help and advice with your plasma cutting challenge