Hebei Juliang Technology Co., Ltd. is one of the leading manufacturers and suppliers of lgk-120 igbt plasma cutting machine in China. Please feel free to buy CE approved machinery made in China here from our factory. All customized machines are with high quality and competitive price.

What Is the LGK-120 IGBT Plasma Cutting Machine?

The LGK-120 is an inverter-based air plasma cutting system rated at 120 amps of output current. Like other plasma cutters, it uses an electric arc to ionize compressed air into plasma-a superheated, electrically conductive gas that melts through metal. The compressed air then blows the molten material out of the cut zone.

The "IGBT" part is what makes this machine different from older designs. Instead of a heavy mains-frequency transformer, the LGK-120 uses IGBT semiconductor switching at high frequency-typically around 20 kHz or higher. This allows the machine to be smaller, lighter, and more responsive than transformer-based units of equivalent output.

We've been integrating the LGK-120 into CNC cutting systems for a few years now. It's not the most powerful machine in the lineup, and it's not the cheapest. But for shops cutting mild steel up to about 25mm on a regular basis, it hits a practical sweet spot between capability and cost.

How This Machine Actually Performs on Different Materials

The LGK-120 runs on compressed air-no oxygen, nitrogen, or argon cylinders required. That simplifies operation and reduces running costs, but air isn't the ideal gas for every material. Here's what we've observed.

Mild steel – This is where the machine performs best. With the LGK-120, you can cut up to 25mm carbon steel reliably, and up to 45mm with reduced speed. The cut edge is clean enough for most structural and fabrication work. On materials under 16mm, the machine cuts noticeably faster than oxy-fuel-roughly twice as fast in our tests.

Stainless steel – The LGK-120 cuts stainless, but air plasma leaves a nitride layer on the cut edge. This layer can affect corrosion resistance. If the part goes into a food-grade or marine environment, you'll need to grind or machine that layer off. One customer in Hebei learned this the hard way-they cut stainless brackets and the edges started rusting within weeks. They switched to nitrogen for stainless work after that.

Aluminum – The machine cuts aluminum effectively, but the arc tends to wander more than on steel. The cut quality is acceptable, not exceptional. For thin aluminum sheet (under 6mm), it's fine. For thicker aluminum or tight-tolerance work, you'd want a different gas setup or a different machine.

Copper and brass – These are possible, but the arc is less stable and consumable wear increases significantly. We generally don't recommend the LGK-120 for copper unless it's occasional work.

The practical takeaway: this machine is a solid choice for shops cutting mild steel as their primary material, with occasional stainless or aluminum. It's not a replacement for laser cutting, and it's not ideal for high-precision work on non-ferrous metals.

What This Machine Is Used For

Based on where we've seen the LGK-120 installed:

Structural steel fabrication – Building frames, machine bases, and heavy equipment components. The speed advantage over oxy-fuel on materials up to 25mm makes a real difference in throughput.

Pressure vessel and boiler work – Thick-walled carbon steel plate, often with beveled edges for welding preparation.

Automotive repair and restoration – Cutting body panels, chassis components, and exhaust parts. The machine is portable enough to move around the shop.

HVAC and sheet metal work – Cutting ductwork, roofing panels, and thin gauge materials.

CNC cutting tables – The LGK-120 is designed to integrate with CNC systems, with arc voltage output signals that CNC height controllers use to maintain consistent torch height.

Troubleshooting Common Issues

We've seen these problems in the field with the LGK-120 and here's what we've found works:

Poor cut quality or incomplete cuts – Four checks: inspect electrode and nozzle for wear, check that the ground clamp is attached to clean metal near the cut zone, verify air pressure is 0.4–0.6 MPa, and confirm cut speed matches the material thickness.

The arc stops mid-cut – Check air supply pressure first-. Also check for worn consumables. The machine has undervoltage and overheat protection that will shut it down automatically.

Excessive dross on the bottom edge – Cut speed is too slow or current is too high. Increase speed or reduce amperage.

Arc wanders or is unstable – Check air quality first. Contaminated air causes arc instability. Also check that the torch is perpendicular to the workpiece.

Machine won't start – Check the input power connection. The LGK-120 requires three-phase 380V ±15%. Also check the torch trigger and the gas pressure.

Everything You Need to Know

How does the LGK-120 compare to a transformer-based plasma cutter?

An inverter machine like the LGK-120 uses IGBT high-frequency switching instead of a heavy 50Hz transformer. It weighs about 46kg-a transformer unit of similar output would be closer to 80kg. The inverter also maintains more stable output during input voltage fluctuations and is more energy-efficient.

What's the maximum thickness the LGK-120 can cut?

The machine cuts up to 25mm carbon steel reliably, and up to 45mm with reduced speed. For reference, the best cutting thickness range is 1–30mm. If you routinely cut over 25mm, you'd want a higher-amperage unit.

What's the most common cause of poor cut quality?

Contaminated air. Moisture or oil in the air stream damages the electrode and nozzle quickly. We recommend a refrigerated air dryer and coalescing filters. The LGK-120 requires clean, dry air at 0.4–0.6 MPa.

Can the LGK-120 be used with a CNC system?

Yes. The LGK-120 is designed for CNC integration with arc voltage output signals that height controllers use to maintain consistent torch height. The output terminal includes a self-reset protective cap for safety.

IGBT inverter plasma cutter