For PVC window manufacturing, the air demand usually lies between 0.6 and 1.3 m³/min at 7 or 8 bar, depending on how many stations run at the same time. A simple line with a saw, a 2-head welder, a corner cleaner and screwdrivers runs on a 7.5 kW 4-in-1 screw compressor such as the K 75 (1.1 m³/min at 8 bar). With a 4-head welder, a profile machining centre and six or more operators, you move up to the K 110 (1.7 m³/min).
Every use of air in a PVC and aluminium window shop, from the saw to the crimper, is covered on our page on the compressor for PVC and aluminium window fabrication. Here, we follow a PVC window from the bar to the finished frame.
Where does air come in on a PVC window line?
A PVC window goes through a series of stations, almost all of them pneumatic:
- Cutting. The double mitre saw cuts both ends of the profile at 45° in a single pass. Cylinders clamp the bar horizontally and vertically during the cut, then the blade feeds forward, often driven by a cylinder too.
- Machining. Drainage slots and the recesses for the espagnolette and handle are made on a pneumatic drilling and milling unit, a copy router or a profile machining centre.
- Reinforcement. Steel reinforcements are slid into the profiles, then screwed in with a pneumatic screwdriver.
- Welding. The welder, with 1, 2 or 4 heads, clamps the profiles, brings in the heating plate, then presses the ends against each other. All of this movement is pneumatic.
- Corner cleaning. The corner cleaner removes the weld bead with knives and cutters driven by cylinders, and blows away the swarf.
- Hardware and glazing. Screwdrivers for the hardware, a blow gun to clean the frame before glazing and packing.
Each of these stations has its manual, with a consumption in l/min or in litres per cycle and a minimum pressure. That is where to read the real values.
How much air does each station use?
As a rough guide, here are orders of magnitude for the machines on a PVC line. They are for a first calculation and should be replaced by the figures from your manuals.
| Station | Indicative average consumption | Type of consumption |
|---|---|---|
| Double mitre saw | around 150 l/min | continuous during production |
| 2-head welder | around 80 to 100 l/min | in cycles |
| 4-head welder | around 150 to 200 l/min | in cycles |
| Corner cleaner | around 200 to 300 l/min | continuous during production |
| Screwdriver | around 200 l/min while running | intermittent |
| Blow gun | around 150 l/min while blowing | intermittent |
The corner cleaner is often the hungriest machine on the line, because it goes through many movements and blows at every corner. Our article on the air consumption of the PVC welder and corner cleaner shows how to convert litres per cycle into l/min.
The step-by-step calculation for a PVC window line
Take a PVC window manufacturer with four operators: a double mitre saw, a 2-head welder, a corner cleaner, two screwdrivers and a blow gun.
- Machines running continuously: corner cleaner 250 l/min and double mitre saw 150 l/min, giving 400 l/min.
- Intermittent stations, counted at half because the air receiver absorbs their peaks: 2-head welder, about 50 l/min, two screwdrivers at 100 l/min each, blow gun at 75 l/min. With four operators, keep the two hungriest stations that come on top of the saw and the corner cleaner: the two screwdrivers, giving 200 l/min.
- Subtotal: 400 + 200 = 600 l/min.
- 25% safety margin for leaks and wear: 600 × 1.25 = 750 l/min.
- 20% expansion margin, if you plan one more machine: 750 × 1.2 = 900 l/min, or 0.9 m³/min (around 32 CFM).
These are the margins our configurator applies. The K 75, with 1.1 m³/min at 8 bar, covers this need and keeps a reserve. If the line moves to a 4-head welder and adds a profile machining centre, redo the calculation: you quickly go beyond 1.1 m³/min, and the K 110 becomes the right choice.
What pressure should you set for PVC machinery?
Note the minimum pressure given in each manual. For saws, welders and corner cleaners, it is often around 6 bar. Add about 1 bar for losses through the dryer, the filters and the pipework: a setting of 7 to 8 bar is enough in the vast majority of workshops.
There is no point going higher "to be on the safe side". Every extra bar increases electricity consumption and makes the network leak more. If a machine at the end of the line flags low pressure, check the pipe diameter and the quick couplings first. Our guide on connecting the compressor to the air network helps you spot restrictions.
Do you need dry air to weld and clean PVC?
Yes, for two reasons. The first concerns the machines: condensate water makes valves and clamping cylinders stick, and a welder whose clamps close badly produces misaligned corners. The second concerns the product: a white or foiled profile blown with air carrying water or oil keeps marks that are visible on delivery.
The K 75 and K 110 include a refrigerated dryer and outlet filtration: the air reaches the machines dry, with no installation to design. Our compressors are lubricated, and it is this filtration that holds back the carried-over oil. For finishing blow guns, add a fine filter at the point of use. Our article on water in compressed air explains where this water comes from and how to drain it.
The pitfalls of PVC window manufacturing
- Forgetting the corner cleaner. People think of the welder first, but it is often the corner cleaner that uses the most air. Its manual is the first one to read.
- Counting every machine at full load. A window line has more stations than operators. Adding up every manual leads to an oversized compressor that runs idle.
- Ignoring leaks. Each machine carries dozens of fittings, cylinders and solenoid valves. The leak cost calculator shows what they add up to.
- An air receiver that is too small. Welding and cleaning cycles create short bursts of demand. The air receiver size calculator checks the volume. The 420 L receiver on the K 75 covers most small lines.
Which model for your PVC window line?
| Situation | Recommended model | Air flow |
|---|---|---|
| Simple line, 3 to 4 operators, 1 or 2-head welder | K 75, 7.5 kW 4-in-1 screw | 1.1 m³/min at 8 bar, 420 L receiver |
| 4-head welder, machining centre, 5 to 8 operators | K 110, 11 kW 4-in-1 screw | 1.7 m³/min at 8 bar |
| Two lines or two shifts | K 150, 15 kW 4-in-1 screw | 2.2 m³/min at 8 bar |
The S and K series are variable speed: the air flow follows the demand of the line, which varies with every welding cycle.
Send us the list of your machines and their manuals with a quote request, or run a first calculation with the configurator.
For your trade: Compressor for PVC and aluminium window fabrication.