Air System: Clean, Dry, and Reliable

A CNC plasma cutter is only as good as the air feeding it. Without clean, dry air, you'll burn through consumables, get inconsistent cuts, and risk damaging your torch. Here's how to build an air system that keeps up.

Compressor Sizing: CFM, PSI & Duty Cycle

Plasma cutters require a steady supply of compressed air. To ensure optimal performance:

• CFM (Cubic Feet per Minute): This is the volume of air the compressor can deliver. Your compressor should deliver at least 1.5 times the CFM your plasma cutter consumes. For example, if your cutter requires 6.7 CFM at 85 PSI, aim for a compressor that provides around 10 CFM at 90 PSI. Each plasma cutter will be different, check the manual.
• PSI (Pounds per Square Inch): This is the pressure of air in the system. Maintain a consistent pressure, typically around 90 PSI, to ensure clean cuts.
• Duty Cycle: Choose a compressor with a duty cycle that matches your cutting needs. A higher duty cycle allows for longer continuous operation without overheating.

Tip: A larger tank (e.g., 60 gallons) can help maintain consistent pressure and reduce the compressor's workload.

Air Drying: Desiccant vs. Refrigerated Dryers

Moisture in compressed air can lead to poor cut quality and reduced consumable life. To combat this:

• Desiccant Dryers:
  • Pros: Achieve very low dew points; ideal for environments requiring ultra-dry air.
  • Cons: Require regular maintenance and desiccant replacement.
• Refrigerated Dryers:
  • Pros: Lower maintenance; suitable for general-purpose applications.
  • Cons: May not achieve as low dew points as desiccant dryers.

Note: In high-humidity environments, combining both types can offer optimal moisture removal.

Moisture Traps: Protecting Your Torch

Even with dryers, moisture can accumulate in the lines:

• Coalescing Filters: Remove oil and fine particulates.
• Desiccant Filters: Further dry the air; beads change color when saturated, indicating the need for replacement.
• Automatic Drain Valves: Prevent water buildup in the compressor tank.

Warning: Moisture can cause the plasma arc to behave erratically, leading to poor cuts and increased wear on consumables.

Best Practices:

• Regular Maintenance: Check and replace filters and desiccant beads as needed.
• Monitor Air Quality: Install moisture indicators to keep an eye on air dryness.
• Proper Line Setup: Use appropriate piping and avoid long runs that can lead to moisture condensation.