A CNC plasma table with a 125 A power source needs, as a rough guide, around 250 to 280 l/min at the torch, at 6 to 8 bar inlet pressure, plus the table's auxiliaries. With a margin, allow about 0.5 m³/min for one table. A 4-in-1 screw compressor such as the K 75 (1.1 m³/min at 8 bar) supplies one table; the K 110 takes over for two tables or a shop that wants spare capacity.
What uses air on a plasma table
- The torch, continuously while cutting. Gouging usually takes more air than cutting.
- The table auxiliaries: downdraft zone dampers, pneumatic marker or scriber, sometimes plate clamping. They use air in bursts; their flow is in the table manual.
- The operator's blow gun, to clean parts and the slats.
Our page on the compressor for plasma cutting covers every plasma setup. Here we size the case of a high-current CNC table.
Step-by-step calculation
Example: a table with a 125 A power source rated at 270 l/min, auxiliaries at 50 l/min according to the table manual, and a blow gun.
- The torch: on a table, the arc is on for most of the program. Count it at 100%: 270 l/min.
- The auxiliaries: 50 l/min.
- The blow gun: about 150 l/min, in bursts, counted at half: 75 l/min.
- Subtotal: 270 + 50 + 75 = 395 l/min.
- 25% margin: 395 × 1.25 = 494 l/min, or about 0.49 m³/min.
With two identical tables and one blow gun: 2 × (270 + 50) + 75 = 715 l/min. With a 25% margin: 894 l/min. With another 20% for future expansion: 1,073 l/min, or about 1.07 m³/min. That is the limit of the K 75: the K 110 becomes the right choice.
Why a screw compressor for a CNC table?
A table cuts whole sheets, program after program. That is continuous duty, the work a screw compressor is designed for, whereas a piston compressor is meant for intermittent use. Between two sheets, while loading, demand falls almost to zero: a variable speed compressor slows down instead of running unloaded, and the pressure stays steady when cutting restarts. See variable speed or fixed speed.
Which model for a 125 A plasma table?
| Situation | Recommended model | Flow |
|---|---|---|
| One 125 A table | K 75, 7.5 kW 4-in-1 screw | 1.1 m³/min at 8 bar, 420 L receiver |
| Two tables, or one table plus hand cutters | K 110, 11 kW 4-in-1 screw | 1.7 m³/min at 8 bar |
| Air treatment already installed | S 110, 11 kW standalone screw | 1.7 m³/min at 8 bar |
| More tables | K 150, 15 kW 4-in-1 screw | 2.2 m³/min at 8 bar |
If the shop also runs a laser cutting machine, which can require up to 16 bar, the L series is designed for it. For the plasma table alone, 16 bar adds nothing. See compressor for laser cutting.
Pitfalls on a plasma table
- The gantry hose. The hose that follows the torch in the cable chain is long. If it is too narrow, pressure drops at the torch while it reads correctly at the compressor. Check on the power source gauge during a cut.
- Fumes and dust. The table gives off fumes and very fine metal dust. Place the compressor well away from the table with a clean air intake: see compressor room installation.
- Wet air. It wears electrodes and nozzles and spoils the cut. Refrigerated dryer, filtration, and a filter at the power source if the maker recommends one. For a specific air class, see our ISO 8573-1 guide.
- Hours add up fast. First service at 500 hours, then every 1,500 hours. On two 8-hour shifts, 1,500 hours is about 94 days of running (1,500 ÷ 16). Keep a service kit in stock.
Send us the data sheets for your power source and table with a quote request, or size the whole setup with the configurator.
For your trade: Compressor for plasma cutting.