A pneumatic air feeder is a compact press feeder that uses compressed air to advance metal strip, or a suitable non-metal strip, into the die by one fixed pitch on every press stroke. Buyers also call it an air feed, air-operated press feed, compressed-air feeder, pneumatic press feeder, pneumatic strip feeder, punch press air feeder or a pneumatic feeder for power press lines. HENLI builds it as the AF series, from AF-1C (50 mm maximum feeding width) to AF-10C (400 mm), with mechanical, E-type, R-type or E+R control.

The best pneumatic feeder model depends on strip width, material thickness, feed length, press speed, and die structure. AF-1C to AF-4C fit smaller widths and shorter feed lengths, while AF-5C to AF-10C cover wider strip and longer feed length. If the die has pilot pins, add R-type pilot release; if the press stroke is too short or too long for the trigger rod, choose E-type; E+R combines both.

Choose an air feeder machine when the job has fixed pitch, moderate precision requirements, simple operation, and a limited automation budget. Choose an NC servo feeder when the line needs programmable feed length, higher precision, frequent product changeover, thicker material, or more complex press synchronization.

Not in its standard form. The mechanical version runs on compressed air only: a striker on the press slide presses the feeder’s trigger rod, so there is no solenoid valve, limit switch or electrical connection. E-type and R-type versions add 24 VDC solenoid valves, each switched by a cam-operated limit switch on the press; the 24 V is taken from the press, and the valve voltage can be customized to your requirement. Every version needs a stable, filtered and lubricated compressed-air supply.

The E-type valve replaces the mechanical trigger rod, so a 24 VDC signal from the press, not the slide, sets when the feeder returns (coil on) and when it feeds (coil off). It suits press strokes that are too short or too long for reliable mechanical triggering. The R-type valve is a pilot release: it opens only the fixed clamp as the die’s pilot pins enter, so the pilots can correct the strip position; it keeps the trigger rod, and the feed pitch does not change. E+R uses both valves and needs no trigger rod.

On the mechanical version the press slide does the timing. While the striker holds the trigger rod down, the fixed clamp grips the strip and the moving clamp returns; when the rod is released, the moving clamp feeds one pitch (also called the progression) while the die is open. On the E-type, a 24 VDC solenoid valve replaces the trigger rod: coil on, the feeder returns; coil off, it feeds. In HENLI’s example timing (0° = top dead center) the E coil is on from about 90° to 270°, and an R valve releases the fixed clamp from about 160° to just past bottom dead center. Final angles depend on your press and die. See how an air feeder works in a press line.

Pilot release lets go of the strip for a moment so the die’s pilot pins can pull it into exact position. Without it, the fixed clamp still holds the strip as the pilots enter, and the pilot can drag the hole. On HENLI air feeders this is the R-type option: a 24 VDC valve opens the fixed clamp for a short window around bottom dead center (about 160° to 185° in our example timing), then closes it again. The HENLI manual also uses R release on drawing operations to keep the material from breaking. Read more: why a stamping feeder needs pilot release.

Yes. An air feeder can work with a coil decoiler and straightener when the decoiler provides a stable loop and the material does not pull directly against coil inertia. For best performance, the feeding height, coil loop, press timing, and die entry line should be checked together.

Rated air pressure for every AF model is 4.5 kg/cm² (about 64 psi). Set the regulator to about 4.5 kg/cm² with the compressor supplying at least 5 kg/cm², and feed the air through a filter-regulator-lubricator unit set to about one drop of oil every 8–12 feed cycles. Air consumption rises with model size, from 26.5 L/min on AF-1C to 182.5 L/min on AF-10C, which is why AF-8C and larger models come with an air storage tank as standard. Low or unstable pressure is a common cause of slipping and inaccurate feeding.

Common causes include unstable air pressure, slipping material, loose feed-length adjustment, incorrect clamp force, poor strip flatness, wrong installation height, worn guide rods, and poor timing between the feeder and punch press.

Start with the air: check the regulator pressure, the lubricator oil level, and the hoses and quick couplings. A feeder that is hard to start or stops feeding usually has a dry or sticking directional valve, or worn seals on the center rod or fixed pistons. Leaks at the exhaust ports point to worn seals or a bent trigger (floating) rod. Inaccurate feeding comes from running faster than the feeder can follow, a loose feed-length setting, worn clamp plates, strip that is too thin or not aligned with the die, or a die without pilots. After a shutdown of more than 12 hours, idle-run the feeder for 3–5 minutes before feeding. Send the model, nameplate and a short video, and we will match the replacement seals or valve.

Yes, it can often be retrofitted because it is driven by compressed air and can operate independently from the press control system. Press stroke, mounting space, feeding height, and die entry line still need checking.

The quotation mainly depends on the AF model size (feeding width, feed length and thickness), the control type (mechanical, E-type, R-type or E+R), options such as the AF-Plus external air tank or a heavy-duty (HD) build, custom work such as an extended stroke, the mounting bracket for your press, and the quantity, packaging and destination. AF-8C and larger models already include a floor stand, solenoid valve and air storage tank. Send your strip and press details for a configuration and price, or read our air feeder price guide.

HENLI is the manufacturer. AF pneumatic air feeders are built in our own factory in Dongguan, China and come with a 2-year warranty. Standard AF models ship within 3 days; lead time for custom builds is confirmed with the quotation. Feeders are shipped factory-direct in reinforced cartons or IPPC-stamped export wooden cases, depending on model size and order quantity.