What Is Plasma and How Does It Work?
Plasma cutting is a thermal cutting technology in which metal is melted locally by a high-velocity stream of ionised gas (plasma).
- Working principle — argon, oxygen or air is turned into plasma and reaches 20,000-30,000°C
- Cuts electrically conductive metals only (steel, stainless steel, aluminium, copper and so on)
- Speed: on thin sheet, many times faster than the laser (3-6 mm)
- Economical on thick work — practical up to 50 mm
- Output: a narrow cut (1-3 mm), with edge oxidation and a thermal effect
- Cost — lower than laser and waterjet (especially on thick steel)
Side-by-Side Comparison
| Criterion | Waterjet | Plasma |
|---|---|---|
| Working temperature | < 60°C (cold) | 20,000-30,000°C (very hot) |
| Heat zone (HAZ) | NONE | Yes (1-3 mm — pronounced) |
| Material range | Almost anything | Conductive metal only |
| Glass, stone, composite | Yes | CANNOT |
| Max. thickness | 300 mm | ~50 mm practical |
| Accuracy | ±0.1 mm | ±0.5-1 mm |
| Kerf width | 0.8-1.2 mm | 2-4 mm |
| Surface quality | Matt (Q1-Q5) | Oxide + dross — cleaning needed |
| Environmental impact | Low (water + garnet) | High (fumes, NOx, noise) |
| Operational input | Garnet + electricity + water | Plasma gas + electricity + consumable electrode |
| Investment | High (UHP pump + treatment) | Medium |
| Installation complexity | High (pump + water system) | Low (compressor + power unit) |
The Jobs Where Plasma Is Strong
- Thick steel (10-50 mm) — industrial sheet and plate cutting
- Structural steel elements — columns, beams, plate
- Shipbuilding — thick stainless steel, aluminium
- Railways — wagon frames, rail systems
- Automotive sub-industry — large metal sheet production
- High-volume series production — speed and cost driven
Where the Waterjet Beats Plasma
- NON-METAL MATERIALS — glass, marble, composite, plastic, food — plasma cannot do them
- HAZ-free cutting required — aerospace, medical, sensitive alloys
- Precision work — ±0.1 mm tolerance (plasma ±0.5-1 mm)
- Narrow cutting stream — minimal waste (plasma has a 2-4 mm kerf)
- Complex internal contours and internal corners
- Environmental constraints — enclosed workshop, no fumes permitted
- Multi-material workshop — a single machine cuts everything
Where Plasma Beats the Waterjet
- A METAL-ONLY WORKSHOP — dedicated to steel and structural work
- HIGH-VOLUME series production — speed brings economy
- THICK STEEL (>10 mm) cutting at low cost
- NO CLEAN ENVIRONMENT required (open workshop)
- A CONTROLLED INVESTMENT BUDGET — plasma is more affordable
- SIMPLE SPARE PARTS stock (electrodes and nozzles are widely available)
Summary Comparison of the Three Technologies
| Factor | Laser | Waterjet | Plasma |
|---|---|---|---|
| Speed on thin sheet (1-6 mm) | ★★★★★ | ★★ | ★★★★ |
| Thick work (>25 mm) | ★★ | ★★★★★ | ★★★★ |
| Marble / glass / composite | ★ (none) | ★★★★★ | ★ (none) |
| HAZ-free precision work | ★★ | ★★★★★ | ★ |
| Surface quality | ★★★★★ | ★★★★ | ★★ |
| Environmentally clean | ★★★ | ★★★★★ | ★★ |
| Investment scope | High | High | Medium |
| Complexity (maintenance) | Medium | High | Low |
Decision Scenarios
Scenario 1: Structural steel workshop
Cutting 20-50 mm thick steel, high volume, no enclosed-workshop standard. → PLASMA
Scenario 2: Combined marble and metal workshop
Marble kitchen countertops + decorative metalwork + composite panel. → WATERJET (a single machine does everything)
Scenario 3: Aerospace sub-industry
Titanium, stainless steel, composites, tight tolerances, AS9100-certified process. → WATERJET (no HAZ is essential)
Scenario 4: Series production of thin sheet (1-6 mm)
High volume, thin steel or stainless steel. → LASER (plasma also works, but the quality is below that of the laser)
Scenario 5: Site cutting
Mobile or portable application, cutting on the spot. → PLASMA (a waterjet needs a fixed installation)
The USEL Approach
USEL does not manufacture plasma machines — our focus is CNC bridge saws, waterjets and sandblasting. If you need plasma, a separate supplier is required; but for multi-material and precision work the waterjet offers a far wider scope. Get in touch through the contact form for a model recommendation to suit your workshop.