Thermal Dynamics

Plasma Gas – What is it?

Plasma gas is gas heated to an extremely high temperature and ionized so that it becomes electrically conductive. The plasma arc cutting and gouging processes use plasma to transfer an electrical arc to the work piece. The metal to be cut or removed is melted by the heat of the arc and then blown away. A plasma arc creates a very clean, dross free cut with minimal heat input, usually requiring very little rework or cleanup.

Advantages of Plasma Cutting

Plasma arc cutting is an excellent choice for most cutting applications but it is particularly well suited for applications where speed and excellent cut quality are important. Because of the intense heat of the plasma arc – around 40,000° F (22,000° C) compared to 5,700° F (3150° C), with gases used with Oxy-Fuel torches – the cut is very clean with little or no dross. The plasma arc also cuts ferrous and non-ferrous metals much faster than an Oxy-Fuel torch or abrasive saws, with low or no heat affected zone, especially on thinner metals. A clean cut with little or no dross means less time and money is required to finish the work piece. Parts are virtually weld-ready.

With plasma cutting, less preparation work is required. A plasma arc is hot enough to burn through most surface coatings such as paint and rust and still provide excellent cutting results. For applications where difficult shapes are being handled or cut, such as ventilation ductwork (HVAC), tanks or vessels, plasma cutting offers considerable advantage since no fixturing is required. All you need is a place on the metal to attach the work clamp. And with plasma cutting, there is also minimal heat input and distortion of the metal as there is with jigsaws or cutting shears.

Thermal Dynamics® Plasma Terminology

  • Genuine Cut - at Thermal Dynamics, our standard cut is called a ‘Genuine Cut’. A ‘Genuine Cut’ is an excellent, smooth cut surface with little or no dross, requiring little or no rework or grinding. It is achieved when cutting at 10” (254mm) and above per minute.
  • Dross Buildup - molten material which is not blown out of the cut area and solidifies on the bottom of the plate.
  • Drag Cutting - with drag cutting you actually drag the tip of the torch along the work piece to cut the metal. This works particularly well on metal 3/16” (4.7mm) thick or less. This is often the easiest way to cut and minimize heat input and kerf width.
  • Standoff Cutting - suitable where material thickness is 3/16” (5mm) or greater, the torch tip is held a distance of 1/8” (3mm) to 3/8” (10mm) from the work piece to achieve the desired cut. Special devices such as standoff guides and cutting guides can help make cutting easier. Cutting guides are particularly useful for cutting thinner metals.
  • Gouging - plasma gouging produces a very smooth, clean surface which is often weld-ready. Plasma gouging can also be successfully used to separate two welds with less noise and less smoke than traditional gouging methods.
  • Piercing - piercing with plasma produces a quick hole through the plate and is recommended on thickness up to 50% of the cutting system’s rating.
  • Front End Parts Visibility - no matter if you are drag cutting or standoff cutting, it is important to be able to see your work while you are cutting. Thermal Dynamics® is known in the plasma cutting business for designing torches with excellent visibility.
  • Consumables Parts - generally refers to the torch tip and torch electrode. These parts must withstand the intense heat of the plasma arc and must be replaced periodically.

Selecting a Thermal Dynamics Plasma Cutting System

These basic questions will help you decide which system best fits your needs:

  • How thick is the metal you want to cut? - We offer a wide range of systems that can handle metal thickness from gauge to 1-1/2". For production applications you’ll want to refer to our literature for automated plasma cutting systems.
  • What cut quality do you require? The cut quality you require will be an important factor in deciding which system is right for you. Cut quality is based on a number of factors - material type, thickness, and gas source. These factors need to be weighed to determine the best system for your needs.
  • What type of metal are you cutting? - Plasma can be used for cutting mild steel, stainless, and aluminum as well as most other metals, with excellent results.
  • What is your primary input power? - This refers to power at the wall or power source. Each plasma system will have a required input current (single or three phase) rated at maximum output based on your input voltage.
  • Gas Supply - Thermal Dynamics manual cutting systems require either air or nitrogen as a gas source – either from a high pressure gas cylinder or most often an air compressor. An air compressor draws on shop air so it is very important to control the air quality and keep it free from contaminants. We recommend purchasing an optional filtering accessory for your plasma system to ensure your system performs at its best.
  • Torch Lead Length - Our plasma systems are usually offered in either 20’ (6.1m) or 50’ (15.2m) lead lengths. (Our 1Torch® RPT® Torch is offered with Lead Extensions in 15’/4.6m, 25’/7.6m, and 50’/15.2m lengths.) How far away from your power source do you intend to operate your plasma cutter?
  • Price - Price is always an important consideration. How much money do you want to spend? Thermal Dynamics is committed to providing customers with quality product at the best value possible. We back our systems and torches with excellent warranties and the best customer and technical service in the industry.

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Phone: 518.885.9685

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