TL;DR — Direct answer: Garment manufacturing needs clean dry air at 7 to 8 bar for cutting, sewing, pressing and packing, with a pressure dew point of 3 degrees C and filtration that keeps oil and water away from fabric. Size on the coincident peak of cutting, sewing and pressing lines, commonly 4 to 10 cubic metres per minute for a mid-size factory, and use a variable speed drive because orders change the line mix every week. This is garment making, downstream of textile mills: the air touches finished fabric, so a single oil spot can reject a whole garment. QiAir, a Chinese screw compressor manufacturer and supplier, sizes machines for this duty.
A garment factory is a sewing floor, a cutting room and a pressing line, and all three run on air. Cutting machines use air for clamping, spreading and knife control, sewing machines use it for clamping, feeding, thread trimming and needle cooling, pressing and finishing stations use it for steam and vacuum controls, and packing lines use it for folding, bagging and strapping. A pressure dip at the cutting table slows the knife, wet air at the pressing station spots the fabric, and oil on a finished garment is a reject that no pressing can fix. QiAir is a Chinese manufacturer and supplier of screw air compressors, and its machines for garment factories are specified around clean, steady air at the workstation.
Garment work is order-driven and changes fast: one week the floor runs shirts, the next it runs jackets, and the line mix and the air load change with it. A compressor sized for a single fixed day will be wrong within a month, so the sizing has to follow the real order pattern. This guide maps the garment air users, explains how to size for a changing line mix, covers fabric protection, and sets out a sizing sheet for a China supplier.
Where Air Is Used: Cutting, Sewing, Pressing and Packing
Cutting is the first air user and the one that sets the pace. Spreading machines, cutting tables and automatic cutters use air for clamping, vacuum hold-down and knife control, and a pressure sag leaves the fabric shifting under the knife, which shows up as a size error across a whole lay. Sewing follows: each machine uses a small amount of air, but a floor of a hundred machines adds up, and the users that matter most are the thread trimmers, the automatic pocket setters and the buttonholers, which all need a fast, reliable pulse.
Pressing, finishing and packing close the line. Pressing stations use air for steam control, vacuum and buck movement, and wet air here spots the fabric or leaves a water mark that only shows after the garment cools. Packing lines use air for folding, bagging, labelling and strapping, and a damp pulse at the bagging head can seal moisture into a polybag. Map the pressing load carefully, because a pressing station left at full steam and air all shift is one of the biggest hidden wastes on a garment floor.
- Cutting: spreading, clamping, vacuum hold-down and knife control where a sag shifts the fabric.
- Sewing: thread trimming, pocket setting and buttonholing across a floor of many small users.
- Pressing and packing: steam and vacuum controls, folding, bagging and strapping where wet air spots fabric.
Sizing for a Line Mix That Changes Every Order
List the lines that run together on a real order, and then test the next order as well, because the mix changes. A mid-size garment factory typically peaks at 4 to 10 cubic metres per minute at 7 to 8 bar, roughly a 30 to 55 kW screw compressor, and a variable speed drive is almost always the right choice because the load follows the order book, not a fixed schedule. A fixed-speed machine that unloads between orders wastes power, while a variable speed machine follows the sewing floor and keeps pressure steady for the cutting tables.
Keep the pressure drop to the farthest cutting table under 0.3 bar at peak, fit a 500 to 1000 litre receiver per 10 cubic metres per minute to absorb changeover spikes, and fit a pressure regulator at each cutting and pressing area so one area cannot starve another. Log pressure at the cutting table during a changeover for a week, because that log is the honest record of whether the compressor is big enough, and it should be repeated whenever a large new order changes the line mix.
- Size on the lines that run together on a real order, and re-check when a new order changes the mix.
- Use a variable speed drive for the order-driven load, and regulate each cutting and pressing area separately.
- Keep far-end drop under 0.3 bar, and log cutting-table pressure during changeovers for a week.
Fabric Safety: Oil, Water and Lint
Fabric is the product, and it shows every air fault. Oil aerosol leaves a spot that no washing removes, moisture leaves a water mark that only appears after pressing, and lint in the air line clogs the small valves on sewing machines. The treatment chain is 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 where the buyer specifies oil-free quality air. Test the air at the pressing station quarterly, and change elements on pressure drop, not on a calendar guess.
Lint is the garment-factory problem that other industries do not have. Cutting and sewing produce fine fibre that clogs intake filters and air-line filters alike, so site the compressor in a clean ventilated room away from the cutting room, duct the intake from clean air, and check the intake filter weekly. Slope lines to drain legs, fit automatic zero-loss drains, and keep the compressor room free of the lint that settles on every surface. Size the dryer for the hottest, most humid month, because a marginal dryer in summer passes wet air into the pressing line at the busiest time of year.
- Fit pre-filter, refrigerated dryer, 0.01 micron coalescing filter and carbon filter where oil-free air is specified.
- Test air at the pressing station quarterly, and change filter elements on pressure drop.
- Site the compressor away from cutting lint, check the intake filter weekly, and drain every low point.
Buying from China: Sizing Sheet for a Garment Factory Compressor
QiAir is a Chinese manufacturer and supplier of screw air compressors, and a garment order should start with an order-pattern sheet. Send the supplier the number of cutting, sewing and pressing lines, the coincident peak at 7 to 8 bar on a typical order and on the largest order, the fabric and buyer air-quality requirements, ambient temperature and humidity, and the distance to the farthest cutting table. Ask for a variable-speed quotation with the part-load power curve at 50 and 75 percent load, and ask the supplier to state the filtration grades and dryer duty in writing.
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 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 cutting table during a changeover in the first production week. Keep a log of pressure, dew point and filter changes, and review it whenever a large new order arrives, because that is when the sizing assumption is most likely to change.
- Send the supplier line counts, typical and largest-order peaks, fabric requirements and farthest-table distance.
- Ask for variable-speed pricing with power at 50 and 75 percent load, and confirm filtration and dryer duty in writing.
- Accept on a full-load test plus dew point and oil checks, then survey cutting-table pressure at a changeover in week one.
Frequently asked questions
What size screw compressor does a garment factory need?
A mid-size garment factory typically needs 4 to 10 cubic metres per minute at 7 to 8 bar, roughly a 30 to 55 kW screw compressor. Size on the cutting, sewing and pressing lines that run together on a real order, re-check when a new order changes the mix, and use a variable speed drive for the order-driven load.
Why does garment air need to be so clean?
Oil leaves a spot no washing removes, moisture leaves a water mark that only appears after pressing, and lint clogs the small valves on sewing machines. A pre-filter, refrigerated dryer, 0.01 micron coalescing filter and carbon filter protect the fabric, and quarterly air tests at the pressing station catch a failing filter early.
How is garment making different from textile mills for air?
Textile mills run spinning and weaving with heavy continuous loads, while garment making is downstream assembly with many small sewing users, cutting tables and pressing stations. The load follows the order book and changes weekly, and the air touches finished fabric directly, so stability and oil-free quality matter more than raw flow.
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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.