Plasma Cutting Guide — Settings, Technique & Equipment

Plasma cutting uses a constricted arc and high-velocity ionized gas to melt and blow metal from the cut. It’s the fastest and cleanest method for cutting steel, stainless steel, and aluminum from sheet metal gauge up to about 1-1/4" thick, depending on machine amperage.

How Plasma Cutting Works

A pilot arc ionizes gas (compressed air in most shop units) into plasma, reaching temperatures above 30,000F. This superheated plasma stream melts the metal while the high-velocity gas jet blows the molten material out through the bottom of the kerf. The result is a narrow, clean cut with a relatively small heat-affected zone compared to oxy-fuel.

Modern inverter-based plasma cutters produce cleaner cuts at lower amperages than older transformer units. A 45A inverter plasma cutter today outperforms a 60A transformer unit from 15 years ago in both cut quality and speed.

Handheld vs. CNC Plasma

Handheld plasma cutters dominate small shops, auto body work, HVAC, and field work. Drag-tip technology on modern units lets you rest the torch cup directly on the workpiece for straighter cuts without a guide. Freehand cutting takes practice, but a straightedge or circle guide produces results close to CNC quality.

CNC plasma tables pair a machine torch with a motorized gantry and computer control. They produce repeatable parts at production speeds. Entry-level CNC tables with a 45A source start around $5,000-8,000 for a 2x2’ or 4x4’ cutting area. Industrial tables with 105A+ sources and water tables run $20,000-80,000+.

Consumable Management

Plasma torch consumables (electrode, nozzle, swirl ring, shield cup) wear with every cut. Average electrode life is 1-3 hours of cutting time, depending on amperage, material, and pierce count. Piercing wears consumables 5-10x faster than edge starts. Replace consumables as a set when cut quality degrades, the arc wanders, or the cut angle increases.

Articles in This Section

The guides below cover amperage-to-thickness settings, consumable selection, air quality requirements, cutting technique for clean edges, and reviews of plasma cutters at every price point.