Oxy-Fuel vs. Plasma Cutting | Everything You Need to Know

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For metal fabricators worldwide, cutting metal sheets and tubes is a daily necessity. A CNC machine capable of cutting metal is essential for any metal fabrication shop. Typically, three types of machines are used for this task:

• CNC Oxy-Fuel Cutting Machine (Oxyacetylene)

• CNC Plasma Cutting Machine

• Fiber Laser Cutting Machine

If your work requires extremely high cutting speed and precision, a fiber laser cutting machine is ideal. However, for most common metal-cutting jobs, a CNC oxy-fuel or plasma cutting machine is sufficient.

So, how should we choose between oxy-fuel and plasma cutting? What are their differences? This article breaks it all down for you.

What Is Oxy-Fuel Cutting?

Oxy-fuel cutting uses a cutting torch to generate an oxyacetylene flame, similar to a welding torch. Here's how it works:

1. The flame preheats the steel to around 870°C or higher.

2. Pure high-pressure oxygen is then sprayed onto the steel.

3. This causes a chemical reaction between the oxygen and the iron in the steel, generating heat and creating molten iron oxide.

4. The molten metal is blown away by the oxygen jet, forming a clean cut.

What Is Plasma Cutting?

Plasma cutting uses plasma, created by ionizing gas with a high-frequency arc. Here’s how it works:

1. The arc ionizes the gas, turning it into plasma.

2. The plasma arc jumps to the workpiece.

3. A high-speed jet (up to 1,000 m/s) of ionized gas melts the metal.

4. The molten metal is then blown away by high-pressure air.

Plasma cutting produces temperatures of up to 2,700°C, which is nearly twice the melting point of steel, allowing it to cut metal very quickly and cleanly.

Oxy-Fuel vs. Plasma Cutting: Key Differences

1. Cutting Material and Thickness

• Oxy-Fuel Cutting is ideal for thick carbon steel.

• Plasma Cutting is better for:

• Thin sheets

• Stainless steel

• Aluminum, copper, and other non-ferrous metals

• High-alloy steels (chromium, nickel, molybdenum)

Plasma cutting is faster and creates a smoother surface with less thermal distortion, especially on thin materials.

2. Cost Comparison

Oxy-Fuel Cutting Cost Example (18mm thick, 1m long steel):

Plasma Cutting Cost Example (Using Hypertherm MAX200):

• Power consumption: 30kW

• Electricity cost: 0.8 RMB/kWh

• Cutting speed: 1,500 mm/min

• Nozzle cost: 20 RMB/hour

Total cutting cost per meter: 0.49 RMB

✅ Conclusion: Plasma cutting is twice as fast and less expensive than oxy-fuel cutting for the same job.

3. Waste Production

• Oxy-Fuel Cutting produces a large amount of slag (iron oxide), requiring extensive cleanup.

• Plasma Cutting produces much less slag, depending on torch design and arc quality.

Final Thoughts

Both oxy-fuel and plasma cutting have their place in metal fabrication:

• Choose oxy-fuel for thicker carbon steel.

• Choose plasma cutting for non-ferrous metals, thin sheets, or when speed and precision matter.

If you're still unsure which cutting method suits your needs, feel free to contact us at HEAVTH. We’re here to provide expert guidance and tailored solutions.

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