TL;DR — Direct answer: A wood furniture factory needs clean, dry air at 6 to 7 bar for CNC routing, edge banding, sanding, vacuum hold-down and spray finishing, with a pressure dew point of 3 degrees C and filtration to 0.01 micron so no oil or moisture reaches a spray gun or a lacquered surface. Size on the coincident peak of CNC machining and the spray booth, 5 to 10 cubic metres per minute for a mid-size plant, roughly a 37 to 75 kW screw compressor with a variable speed drive. QiAir, a Chinese screw compressor manufacturer and supplier, builds fixed and variable speed machines with oil-free air treatment for furniture factories.
A wood furniture factory runs on compressed air from the first cut to the final coat. CNC routers shape panels, doors and chair parts, edge banders apply and trim edge tape, sanders prepare surfaces for finishing, veneer presses glue and clamp, and spray booths lay down lacquer, stain and topcoat. A pressure dip at the CNC router slows the tool change and leaves a burn mark on a panel edge, moisture in the spray air causes blushing and fisheyes in a lacquer finish, and oil on a veneer surface stops glue from bonding. The air system is part of the finishing quality, not just a utility. QiAir is a Chinese manufacturer and supplier of screw air compressors, and its machines for furniture plants are specified around clean, dry air first and flow second.
The mistake buyers make most often is sizing air on the CNC machines alone and forgetting the spray booth and the sanding line. CNC routing runs in bursts as panels change over, edge banding is steady, and the spray booth draws a constant flow while guns are open, with blow-off cleaning at the end of every batch adding a heavy short load. Add them together at peak and the real demand is typically 20 to 30 percent higher than the first estimate. This guide maps where the air goes in a furniture factory, explains how to size for CNC and spray peaks, sets the clean-air standard that protects lacquer finishes, and shows what to put on a sizing sheet for a China supplier.
Where Air Is Used: CNC Routing, Edge Banding, Sanding and Spray Finishing
CNC routing is the heaviest user. Routers use air for tool changes, vacuum hold-down of panels, dust extraction dampers and spindle cooling, and the demand spikes each time a new panel is loaded and clamped. Vacuum hold-down is the hidden consumer: a leaking vacuum table or a panel that does not seal well forces the vacuum generator to run constantly, and a venturi vacuum generator fed by compressed air can use several cubic metres per minute on its own. Fit a dedicated vacuum pump where hold-down runs all day, and keep the CNC air branch filtered and dry, because a puff of moisture on a freshly routed edge swells the fibres and shows through the lacquer.
Edge banding, sanding and spraying take the rest of the air and set the quality standard. Edge banders use it for tape feed, pressure rollers and trimming, sanders use it for belt tracking, cleaning nozzles and dust extraction control, and spray booths use it for HVLP and conventional guns, booth dampers and parts cleaning. Sawdust is fine and everywhere, so every air tool and valve in the machining hall needs filtration that survives it, and any open blow-off nozzle wastes air fast if operators leave it running between panels. A plant that maps every user, including the cleaning lances at the end of the sanding line, usually finds 20 to 25 percent more demand than the original estimate.
- CNC routing: tool changes, vacuum hold-down and dust extraction dampers that spike at every panel change.
- Edge banding and sanding: tape feed, trimming, belt tracking and cleaning nozzles across the machining hall.
- Spray finishing: HVLP guns, booth dampers and parts cleaning that need dry, oil-free air.
Sizing for CNC Peaks and Spray-Booth Demand
List every line with its flow at peak and at steady running, because the two differ sharply in furniture work. A mid-size plant with three to six CNC routers, two edge banders, a sanding line and two spray booths typically peaks at 5 to 10 cubic metres per minute at 6 to 7 bar, which is roughly a 37 to 75 kW screw compressor, and the peak usually lands when CNC changeovers coincide with both booths spraying. A variable speed drive earns its keep here: it follows the batch pattern of CNC work instead of loading and unloading a fixed-speed machine dozens of times a shift, and it holds pressure within the narrow band that spray guns prefer.
Keep the pressure drop to the farthest spray gun under 0.3 bar at peak flow, and fit a receiver of 500 to 1000 litres per 10 cubic metres per minute to absorb CNC tool-change and blow-off spikes. A ring main helps when the CNC hall, sanding line and spray shop sit in different parts of the building. Log pressure at the farthest spray gun during a full production run for a week, because that log is the honest record of whether the compressor is big enough, and it settles arguments faster than any catalogue figure. Never raise the set point to mask a sag: every extra bar adds roughly 7 percent to power use and hides the real fault, which is usually a clogged filter or an undersized pipe.
- Size on the coincident peak of CNC changeovers and both spray booths, not on steady-state average flow.
- Use a variable speed drive for batch CNC loads, and keep far-end pressure drop under 0.3 bar.
- Log farthest-gun pressure during production for a week to prove the sizing in real use.
Clean Dry Air: Protecting Lacquer Finishes from Fisheyes and Blushing
Oil and moisture are the two contaminants that ruin a furniture finish, and both are invisible until the lacquer cures. A drop of oil carried through a spray gun leaves a fisheye in the topcoat, moisture in the spray air causes blushing, a milky haze in lacquer, and damp air blown onto a veneer before pressing weakens the glue bond. The standard that prevents this is a treatment chain, not a single filter: a pre-filter, a refrigerated dryer to a 3 degree C pressure dew point, a coalescing filter to 0.01 micron, and an activated-carbon filter for oil vapour, with a final point-of-use filter at each spray booth. For spray guns and veneer pressing, an oil-free screw compressor removes the oil risk at source rather than filtering it out.
Sawdust needs its own discipline. Keep the compressor intake away from the machining hall so the machine does not breathe wood dust, fit a heavy-duty intake pre-filter, and check it weekly in the first months. Drain condensate with automatic zero-loss drains, slope lines to drain legs, and keep the compressor room clean, ventilated and cool. Change coalescing elements on pressure drop, not on a calendar guess, and test the air at the farthest spray booth quarterly for oil, moisture and particles, because a slow rise in dew point is the earliest sign that a dryer needs attention before finished furniture starts failing inspection.
- Fit pre-filter, refrigerated dryer, 0.01 micron coalescing filter and carbon filter, with a final filter at each booth.
- Consider an oil-free screw compressor for spray guns and veneer pressing, where air contacts the finish directly.
- Keep the compressor intake away from sawdust, and test spray-booth air quarterly for oil and moisture.
Buying from China: Sizing Sheet for a Furniture Factory Compressor
QiAir is a Chinese manufacturer and supplier of screw air compressors, and a furniture order should start with a sizing sheet that names the booth count. Send the supplier the number of CNC routers, edge banders and spray booths, the coincident peak at 6 to 7 bar, the air-quality standard the spray guns require, ambient temperature and humidity, and the distance to the farthest booth. Ask for a quotation that states the dryer type and filtration grades explicitly, and ask whether an oil-free machine or a filtered oil-injected machine fits the finishing specification better, with the cost and maintenance difference spelled out.
Agree the acceptance test before shipment: a full-load run at rated pressure, a dew point reading at the dryer outlet, and an oil-aerosol check at the final filter outlet. On arrival, install on a level plinth with clear cooler airflow, connect drains before the first run, and survey pressure at the farthest spray gun during the first full production week. Keep a log of pressure, dew point and filter changes, and review it monthly, because a slow rise in dew point is the earliest sign that a dryer needs attention before lacquer finishes start failing inspection.
- Send the supplier CNC, edge bander and booth counts, coincident peak and farthest-booth distance.
- Ask for dryer type and filtration grades in writing, and compare oil-free against filtered oil-injected on total cost.
- Accept on a full-load test plus dew point and oil-aerosol checks, then survey pressure at the farthest gun in week one.
Frequently asked questions
What pressure does a furniture factory need?
A wood furniture factory needs clean, dry air at 6 to 7 bar for CNC routing, edge banding, sanding and spray finishing. Keep far-end pressure drop under 0.3 bar, because a pressure dip at the spray gun changes the atomisation and leaves an uneven finish, and size on the coincident peak of CNC changeovers and both spray booths.
Why must furniture spray air be oil-free?
A drop of oil carried through a spray gun leaves a fisheye in the lacquer topcoat, and moisture in the spray air causes blushing, a milky haze in the finish. A pre-filter, refrigerated dryer to a 3 degree C pressure dew point, 0.01 micron coalescing filter and carbon filter in series protect the guns, and an oil-free screw compressor removes the oil risk at source.
What size screw compressor does a furniture factory need?
A mid-size furniture plant with three to six CNC routers, two edge banders, a sanding line and two spray booths typically needs 5 to 10 cubic metres per minute at 6 to 7 bar, roughly a 37 to 75 kW screw compressor with a variable speed drive. Add a 500 to 1000 litre receiver per 10 cubic metres per minute, and verify pressure at the farthest spray gun under full load.
Related reading
- How to Choose the Best Screw Air Compressor Manufacturer in China for Your Factory
- Two-Stage PM VFD Screw Compressors: How a Top China Supplier Cuts Factory Energy Costs
QiAir is a Chinese manufacturer and supplier of screw air compressors. If you are sourcing a screw compressor from China — for a factory, a food plant, a construction site or a new production line — contact QiAir for a sized quotation, documented performance data and export support.