Glass processing and glazing

Compressor for glass processing, glaziers and double glazing

Air compressor for glass processing and glaziers - cutting tables, IGU lines, edging machines, glass sandblasting. Air flow worked out, dry air with no marks.

A glass and glazing workshop that cuts, edges and washes glass uses around 1,000 to 1,400 l/min once the margins are added: an 11 kW 4-in-1 screw compressor such as the K 110 (1.7 m³/min at 8 bar) covers it. With a double glazing (IGU) line, demand rises towards 2,000 l/min and a K 150 (2.2 m³/min). With a sandblaster for frosted glass, demand often exceeds 3,000 l/min and calls for an S 220 PM. In every case the air must be dry and filtered: a drop of water or oil on glass shows.

What is compressed air used for in glass processing?

Flat glass passes through a series of machines that almost all draw on the air network:

The cutting table. Compressed air presses the cutting wheel onto the glass at a set pressure, operates the breaking bars and, on some tables, feeds the air cushion that lets large sheets glide. Other tables produce this cushion with a built-in fan: check the manual.
The insulating glass line. Washer, assembly station, press and conveyors are driven by pneumatic cylinders and valves.
Edging and arrissing machines. Double edgers, straight-line edgers and arrissing machines clamp and feed the glass with cylinders and grippers.
The sandblaster. For frosted glass and decorative work, it is by far the hungriest station.
Vacuum lifters. Pneumatic models create the vacuum by venturi effect and use air for as long as they hold the sheet.
Washing and drying. The washing machine's valves are pneumatic, and nozzles blow remaining water off edges and small pieces.
The toughening furnace. Toughening itself is done by powerful fans blowing onto the hot glass, not by the compressor. Compressed air is used for the furnace's automation: doors, rollers, valves.

These uses have one thing in common: the glass is the finished product. Whatever comes out of a nozzle or a suction cup ends up on the surface the customer will look at.

How much air does a glass workshop use?

The figures below are indicative only, at around 6 bar. The exact consumption is in each machine's manual.

Station	Consumption of around
Cutting table (cutting wheel, breaking)	150 to 400 l/min
Insulating glass line (press, cylinders, conveyors)	300 to 600 l/min
Edging or arrissing machine	100 to 200 l/min
Venturi vacuum lifter	80 to 150 l/min while gripping
Sandblaster, 3 mm nozzle	about 500 l/min
Sandblaster, 4 mm nozzle	about 900 l/min
Blow gun	150 to 250 l/min while blowing

The step-by-step calculation

Take a medium-sized glass and glazing workshop, using the figures in the table:

Cutting table: 250 l/min.
Two edging machines: 2 × 150 = 300 l/min.
Washing machine (valves and blow-off): 100 l/min.
Two vacuum lifters used in bursts, counted at 50%: 120 l/min.
Two blow guns, counted at 50%: 150 l/min.

Total: 920 l/min. Our configurator adds a 25% safety margin (920 × 1.25 = 1,150 l/min), then 20% for a future machine (1,150 × 1.2 = 1,380 l/min). The demand is therefore about 1.4 m³/min.

Add an insulating glass line at 400 l/min: 1,320 l/min before margins, or 1,980 l/min with them. Add a sandblaster with a 4 mm nozzle as well: 2,220 l/min before margins, or 3,330 l/min. The flow and pressure converter converts l/min into m³/min and into the CFM used in machine manuals.

Which compressor should a glass workshop choose?

Independent glazier, one table and one edger: the K 75, a 7.5 kW 4-in-1 screw compressor, gives 1.1 m³/min at 8 bar with a 420 L air receiver, refrigerated dryer and filtration on the same frame.
The example workshop, with cutting, edging and washing: the K 110, 11 kW, 1.7 m³/min at 8 bar, 340 L receiver.
With an insulating glass line: the K 150, 15 kW, 2.2 m³/min at 8 bar.
With a sandblaster or several lines: the S 220 PM, 22 kW with a permanent magnet motor, 3.6 m³/min at 8 bar, with a separate dryer and filtration. Beyond that, the S series goes up to 132 kW on quotation.

The S and K series are variable speed. In glass processing, demand changes constantly: the table breaks, the press closes, the sandblaster starts and then stops. The compressor follows these changes instead of switching between load and idle. All our models run on 380 V three-phase.

What pressure do glass machines need?

Most machines need around 6 bar at their inlet. Allowing for losses through the dryer, filters and pipework, setting the compressor at around 7 to 8 bar is enough. Glass sandblasting often works lower, around 2 to 5 bar depending on the thickness and the design: a regulator at the station does the job, with no need to raise the pressure across the whole network.

Why must the air be dry and clean?

Glass forgives nothing. A blow gun that spits water leaves limescale rings. A trace of oil on a face that will be assembled into an insulating glass unit interferes with the bonding of the seal and can reappear between the two panes, where nobody can clean it any more. A suction cup that has drawn in damp air marks the surface.

The basis is a refrigerated dryer plus filtration of particles and oil aerosols, as on the K series. Our compressors are oil-lubricated: it is the outlet filtration that captures carried-over oil. As close as possible to sensitive stations (blow-off after washing, assembly station), add fine filters, plus an activated carbon stage if the air touches a face to be bonded. The ISO 8573-1 quality class is defined with our technicians. If the air runs through a cold building in winter, a desiccant dryer prevents condensation in the pipes.

Articles to go further

Which compressor for a glazier: three typical workshops and their model.
Insulating glass line: air flow and air quality.
Air cushion cutting table: which compressor.
Glass sandblasting and frosting: nozzle and air flow.
Marks on glass: dry air and filtration.

Installation and maintenance

The room. Glass dust from edging and sandblasting is abrasive. Install the compressor in a separate, ventilated room, with its intake away from the machines. See the compressor room.
Condensate. An automatic condensate drain on the receiver and at the low points of the network. The condensate contains oil: it must be collected and treated.
Leaks. Suction cups, hoses and quick couplings wear quickly. The leak cost calculator puts a figure on them.
Servicing. First service at 500 hours, then every 1,500 hours. Keep a service kit in stock and change the filter elements when they are due. 2-year warranty, parts available for 15 years.

To size your installation, enter your machines in the configurator, or send us the list of your stations with a quote request.

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Typical tools in this trade

Tool	Consumption	Typical number
Glass cutting table (cutting wheel, breaking, air cushion)	≈ 250 l/min	1
Glass edging / arrissing machine (cylinders)	≈ 150 l/min	2
Insulating glass line (press, cylinders, conveyors)	≈ 400 l/min	1
Glass sandblaster / frosting, 4 mm nozzle	≈ 850 l/min	1
Vacuum lifter with suction cups (venturi)	≈ 120 l/min	2
Machine cylinders and automation	≈ 100 l/min	1
Blow gun	≈ 150 l/min	2

Indicative average consumption. The configurator calculates your exact demand.

AIRSTAHL Lab

Recommended air quality

Painting and finishing — Dry, filtered air for paint and clearcoat spray guns.

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Frequently asked questions — Glass processing and glazing

Which compressor for a glass and glazing workshop?

A glass workshop with a cutting table, two edging machines, a washer and vacuum lifters uses around 920 l/min, or about 1,380 l/min with 25% for safety and 20% for expansion. An 11 kW 4-in-1 screw compressor such as the K 110, 1.7 m³/min at 8 bar, covers it. An independent glazier with a table and an arrissing machine manages with a K 75 (1.1 m³/min).

How much air does a glass cutting table use?

As a rough guide, a cutting table uses around 150 to 400 l/min at about 6 bar for the cutting head, breaking and, on some tables, the air cushion. If the air cushion comes from a built-in fan, do not count it in the compressor's flow. Check the exact value in the table's manual.

What air flow for an insulating glass line?

An insulating glass line uses around 300 to 600 l/min at about 6 bar for its washer, conveyors, cylinders and press, as a rough guide. Added to cutting and edging, it often brings demand towards 2 m³/min with the margins, which corresponds to a K 150 (2.2 m³/min at 8 bar). A buffer receiver near the press prevents pressure drops.

Which nozzle and what air flow for frosting glass by sandblasting?

A 3 mm nozzle uses around 350 l/min at 4 bar and a 4 mm nozzle around 600 l/min, as a rough guide. Glass is generally blasted between 2 and 5 bar depending on the thickness and the design. A nozzle worn by 1 mm uses 50% more air, so check it regularly. See glass sandblasting and frosting.

Is the compressor used to toughen glass?

No. In a toughening furnace, the heated glass is rapidly cooled by powerful fans, not by compressed air. The compressor only supplies the furnace's automation, such as doors and valves, which use little air. Count them with the workshop's other cylinders, around 100 l/min as a rough guide.

Why does compressed air leave marks on glass?

Rings come from condensed water, a greasy film from carried-over oil and specks from particles in the network. A refrigerated dryer, filtration at the compressor outlet and fine filters at the station solve most cases. For air that touches a face to be bonded, add an activated carbon stage.

Is an oil-lubricated screw compressor suitable for glass processing?

Our screw compressors are oil-lubricated: carried-over oil is captured by the outlet filtration, which is built into the K series. For stations where the air touches the glass, such as blow-off after washing or insulating glass assembly, add fine filters and activated carbon at the point of use. The ISO 8573-1 class to aim for is defined with our technicians.

What pressure should be set for glass machines?

Most cutting tables, edging machines and insulating glass lines need around 6 bar at their inlet. Allowing for losses through the dryer, filters and pipework, set the compressor between 7 and 8 bar. The glass sandblaster, which works at a lower pressure, is set at the station with a regulator.