An aluminium profile machining centre needs dry, filtered air, because the air drives the clamps, the tool changer and often the minimum quantity lubrication of the tools. The basic treatment is a refrigerated dryer, which brings the pressure dew point down to around 3 °C, followed by particle and oil aerosol filtration. As a rough guide, a machining centre uses around 100 to 200 l/min: a 4-in-1 screw compressor such as the K 110, with a built-in dryer and filtration, supplies the centre and the rest of the workshop.
The machining centre is only one machine in a PVC and aluminium window shop. Our page on the compressor for PVC and aluminium window fabrication covers the whole workshop; here, we focus on the air quality at this station.
What is air used for on a profile machining centre?
A profile machining centre drills, mills and taps aluminium or PVC profiles along their whole length: hardware recesses, drainage holes, joint notches. Compressed air plays several roles there:
- pneumatic vices that clamp the bar, often four to eight along the table;
- the tool changer and the release of the tool in the spindle;
- minimum quantity lubrication, which sprays a mist of cutting oil onto the tool, carried by the air;
- blowing off aluminium swarf, during and after machining;
- pneumatic stops and guards.
As a rough guide, all of this adds up to around 100 to 200 l/min in production. The minimum quantity lubrication and the blow-off run continuously during machining, which makes the centre one of the steadiest consumers in the workshop. The exact value is in the machine's manual.
Why must the air be dry at this station?
Air leaves the compressor hot and laden with water vapour. As it cools in the network, this vapour condenses. On a machining centre, the water does damage in several ways:
- It upsets the minimum quantity lubrication. The oil is metered drop by drop; mixed with water, it forms an emulsion that clogs the nozzles or reaches the tool unevenly. The result: a tool that overheats, aluminium sticking to the cutting edges, a poorer surface finish.
- It makes the valves and cylinders stick on the vices and the tool changer, which end up in fault.
- It stains the profiles. On powder-coated or anodised aluminium, a drop of oily water leaves a mark that has to be cleaned off before assembly.
- It freezes in winter in pipes that run through an unheated bar store.
Our article on water in compressed air puts figures on these quantities: an 11 kW compressor can produce several litres of water a day in summer. Regular draining of the air receiver and the low points is therefore essential.
Which dryer for a profile machining centre?
The choice depends on the lowest temperature the air meets in your network.
| Situation | Recommended dryer | Pressure dew point |
|---|---|---|
| Network inside a heated or temperate workshop | refrigerated dryer | around 3 °C |
| Pipes running through a store or a yard exposed to frost | desiccant dryer, at least for that branch | well below 0 °C |
In the vast majority of window fabrication shops, the refrigerated dryer is enough. The K 110 and the K 75 include one as standard, with filtration, on the same frame. If part of the network is exposed to frost, a desiccant dryer is specified with our technicians. Our guide to the pressure dew point explains how to choose between the two technologies.
What filtration for machining air?
Our compressors are lubricated: a small quantity of oil is carried over with the air, and it is the outlet filtration that holds it back. For a profile machining centre, the usual layout is:
- at the compressor outlet: refrigerated dryer and particle and oil aerosol filtration, built into the 4-in-1 models;
- at the machining centre: a fine filter that stops rust or scale particles dislodged from the network;
- on the minimum quantity lubrication circuit: the filtration specified by the system's manufacturer.
If the machine maker specifies an air quality class, note it from the manual and define the treatment with our technicians using the ISO 8573-1 air quality guide. Change the filter elements on schedule: a saturated filter no longer protects and costs you pressure.
The step-by-step calculation for a machining centre and its surroundings
Take an aluminium workshop with five operators: a profile machining centre, a double mitre saw, a corner crimper, two screwdrivers and a blow gun.
- Continuous stations: machining centre 150 l/min and double mitre saw 150 l/min, giving 300 l/min.
- Intermittent stations, counted at half because the air receiver smooths out their peaks: two screwdrivers at 100 l/min and a blow gun at 75 l/min, giving 275 l/min. The crimper, at 40 l/min once counted at half, stays outside the five hungriest stations.
- Subtotal: 300 + 275 = 575 l/min.
- 25% safety margin: 575 × 1.25 = 719 l/min.
- 20% expansion margin, for a second centre or a PVC line: 719 × 1.2 = 863 l/min, or about 0.86 m³/min (around 30 CFM).
These are the margins used by our configurator. The K 75, with 1.1 m³/min at 8 bar, covers this need. If the workshop adds a second machining centre, the need exceeds 1 m³/min with the margins and the K 110, at 1.7 m³/min, becomes the right choice. If you already have a recent dryer and air receiver, the S 150, a 15 kW stand-alone compressor delivering 2.2 m³/min, suits larger workshops.
What pressure for a profile machining centre?
The manual gives a minimum inlet pressure, often around 6 bar. Below that, the machine's pressure switch stops the cycle. Set the compressor to 7 or 8 bar and check the pressure at the centre during a tool change, with the saw and the screwdrivers running.
The pitfalls to avoid
- Old steel pipework. Rust comes away and clogs the minimum quantity lubrication nozzles. A fine filter at the machine holds it back.
- Low points with no drain. Water collects there even with a dryer, if the dryer develops a fault. An automatic condensate drain at each low point means nothing gets forgotten.
- Forgotten blow-off. A nozzle left open between two bars uses air for nothing. Our article on blowing off swarf offers some ideas.
To define the air supply for your machining centre, start with the configurator or send us its manual with a quote request.
For your trade: Compressor for PVC and aluminium window fabrication.