A typical SMT line, with two placement machines, a stencil printer and its loaders, uses around 400 L/min continuously. With a margin, one line needs about 0.6 m³/min, two lines about 1.1 m³/min and three lines about 1.7 m³/min. These are orders of magnitude: the real figure comes from your machines' data sheets.
What uses air on an SMT line
On a surface mount line, compressed air feeds several stations. The values below are indicative, at a working pressure of about 6 bar. The exact consumption is on each manufacturer's data sheet.
| Station | Indicative consumption | Operation |
|---|---|---|
| Placement machine (pick and place) | 50 to 200 L/min | Continuous |
| Solder paste stencil printer | 20 to 50 L/min | Continuous |
| PCB loader or unloader | 10 to 30 L/min | Continuous |
| Blow gun at the station | 150 L/min | In bursts |
The reflow oven uses little compressed air. If it runs under nitrogen, that gas comes from a source other than the compressor.
For the whole workshop, our page on compressors for electronics assembly adds screwdrivers and test benches. Here we focus on the lines.
Step by step calculation for one line
Take a line with two placement machines.
- Placement machines: 2 × 150 L/min = 300 L/min.
- Stencil printer: 40 L/min.
- Loader and unloader: 2 × 20 L/min = 40 L/min.
- Conveyors and small cylinders: 20 L/min.
- Line total: 300 + 40 + 40 + 20 = 400 L/min.
Add the blow gun. It blows in bursts, so count it at half: 75 L/min. That gives 475 L/min.
Then apply a 25% margin for leaks and consumption peaks: 475 × 1.25 = 594 L/min, about 0.6 m³/min. Our flow and pressure converter turns L/min into m³/min if a data sheet uses another unit.
Two and three lines
Multiply the line consumption, not the blow guns, which never all blow at once.
- Two lines: 2 × 400 = 800 L/min, plus one blow gun at half (75 L/min): 875 L/min. With the margin: 875 × 1.25 = 1,094 L/min, or 1.1 m³/min.
- Three lines: 3 × 400 = 1,200 L/min, plus two blow guns at half (150 L/min): 1,350 L/min. With the margin: 1,350 × 1.25 = 1,688 L/min, or 1.7 m³/min.
If you plan to add a line in the next few years, add another 20% for expansion.
Which compressor for 1, 2 or 3 lines?
| Requirement (margin included) | Recommended model | Flow at 8 bar |
|---|---|---|
| 1 line, 0.6 m³/min | K 75 | 1.1 m³/min |
| 2 lines, 1.1 m³/min | K 110 | 1.7 m³/min |
| 3 lines, 1.7 m³/min | K 150 | 2.2 m³/min |
| Network already fitted with a dryer | S 150 | 2.2 m³/min |
For two lines, the K 75 would be right at its limit with 1.1 m³/min: it would run with no reserve. The K 110 leaves headroom. Three lines follow the same logic: the K 110 would be at its limit, while the K 150 keeps a margin for a fourth.
K Series models combine compressor, receiver, refrigerated dryer and filtration. They run at variable speed: when a line stops for a changeover, the compressor slows down instead of running unloaded. Our article on variable speed vs fixed speed explains this.
Pitfalls specific to SMT lines
- Continuous operation. An SMT line sometimes runs two or three shifts. A screw compressor handles that pace. A piston compressor, designed for intermittent use, does not.
- Leaks. A line has dozens of quick couplings and hoses. A leak of a few L/min per machine soon adds up. Our article on compressed air leaks explains how to find them.
- Pressure. The machines work at around 6 bar. A compressor set to 8 bar covers the pressure drop in the network. There is no point going higher: every extra bar costs energy.
- Air quality. The nozzles and vacuum generators of placement machines are sensitive to water, oil and particles. Plan for a dryer, filters and automatic drains.
To compare models, use the configurator, then send us the list of your lines in a quote request: we will check the sizing with you.
For your trade: Compressor for electronics manufacturing and assembly.