What Is Plasma Cutting?

Plasma cutting is one of the fastest, most versatile ways to cut metal—whether you’re fabricating custom parts in a shop, repairing heavy equipment in the field, or creating an intricate art piece. This guide covers the science behind plasma, how the process works, where manual and CNC systems shine, and how Thermal Dynamics Cutmaster 70+ and Cutmaster 30+ slot into real workflows.

What Is Plasma?

Plasma is the fourth state of matter. When a gas is heated to very high temperatures, its atoms ionize—electrons separate from nuclei—and the gas becomes electrically conductive. Lightning and the sun are natural examples. Inside a plasma torch, we create plasma on demand and channel it through a precisely shaped nozzle.

That conductivity is the key: a plasma arc carries electrical current and concentrates intense heat through a tiny orifice, producing a narrow, high‑energy jet that melts metal rapidly with a tight kerf.

What Is Plasma Cutting?

Plasma cutting is a thermal cutting process that uses a concentrated jet of superheated, ionized gas to melt and eject material from a cut path. The arc forms between an electrode in the torch and the grounded workpiece, with temperatures often exceeding 20,000 °C.

• Works on any electrically conductive metal (steel, stainless, aluminum, copper, etc.).
• Often faster than oxyfuel on thin to medium thicknesses.
• Produces a narrow kerf with limited heat distortion.
• Can pierce directly—no pre‑drilling required.

Example: The Cutmaster 70+ makes clean cuts in 3/4" (19 mm) mild steel at production speeds, while the ultra‑portable Cutmaster 30+ excels on lighter fabrication and field work.

Manual vs CNC Plasma Cutting

Manual Plasma Cutting

• Hand‑guided torch; quick to set up and highly flexible.
• Ideal for maintenance, mobile jobs, irregular shapes, and small batches.
• Cut quality depends on operator skill and torch handling.
• Best fit: MRO, construction, field service, and one‑off work.

Cutmaster 30+ is built for this style—light, rugged, and easy to carry.

CNC (Mechanized) Plasma Cutting

• Torch mounted to a table/gantry; motion controlled by computer.
• High precision and repeatability for production parts and complex shapes.
• Higher upfront investment; significantly boosts throughput.
• Best fit: batch work, nested parts, and tighter tolerance jobs.

While the Cutmaster 70+ is sold as a manual system, you can equip it with a machine torch and CNC interface to automate workflows—an efficient bridge for shops seeking both manual versatility and entry‑level mechanized capability.

How Does Plasma Cutting Work?

1. Power up: The power supply delivers DC current to the torch electrode.
2. Gas pre‑flow: Compressed air (or another gas) stabilizes pressure and cools the torch.
3. Pilot arc: A low‑energy arc forms inside the torch between the electrode and nozzle, ionizing the gas stream.
4. Main arc transfer: As the torch approaches the workpiece, the arc “jumps” to the metal and forms a conductive plasma channel.
5. Cutting: The plasma jet melts a narrow path as high‑velocity gas ejects molten metal, creating the kerf.

Quality variables: Amperage, gas type and pressure, torch standoff, and travel speed. Too slow → dross; too fast → incomplete cuts. Too high a standoff widens the kerf; dragging the tip can damage consumables.

For a deeper technical dive (consumables, arc density, pressure tuning), see How Does a Plasma Cutter Work?

Meet the Thermal Dynamics Cutmaster 70+ and 30+

Thermal Dynamics (an ESAB brand) has led plasma innovation for decades. The Cutmaster line blends portability, cut performance, and durability.

Shared traits: Honest True‑Cut ratings, user‑friendly 1Torch® ergonomics, and arc stability designed for clean, square edges with minimal rework.

When to Use Plasma Cutting

• Fabrication shops: Brackets, frames, base plates, custom components.
• Maintenance & repair: Remove damaged plate, free seized fasteners, salvage parts.
• Construction: Trim beams, floor plates, and pipe on‑site.
• Automotive: Body panels, chassis work, exhaust fabrication.
• Art & signage: Intricate shapes with clean edges and minimal cleanup.

On thin‑to‑medium materials, plasma often outpaces oxyfuel for speed and distortion control. For very thick plate, consider mechanized plasma or oxyfuel depending on material and tolerance needs.

Safety Tips

• Wear flame‑resistant clothing and gloves; use a helmet with appropriate shade (#5–#9 typical for handheld plasma).
• Use eye and hearing protection; plasma arcs are bright and loud.
• Ensure ventilation or fume extraction when cutting indoors.
• Inspect power leads, work clamp, gas hoses, and consumables before use.
• Keep air clean and dry (filters/dryers); moisture causes sputter and poor cut quality.
• Practice on scrap of the same thickness to confirm settings before production cuts.

Related Topics to Explore

1. How Does A Plasma Cutter Work?
2. Choosing the Right Plasma Cutter: Cutmaster 30+ vs 70+
3. Plasma Cutting Aluminum & Steel
4. Arc Density and Why It Matters for Plasma Cutting Performance
5. How Air Pressure Affects Plasma Cut Quality (And How to Dial It In)
6. The Evolution of Inverter Technology in Plasma Cutting Systems
7. Understanding Pilot Arc Technology: Clean Starts, Every Time
8. HF Ignition in Plasma Cutting: What It Is and When to Use It
9. How Cutmaster Machines Pay for Themselves