Pneumatic hammers then, hydraulic and mechanical presses now
For much of the last century, many smithies and forge shops ran steam or compressed-air drop hammers and self-contained pneumatic hammers. In a self-contained hammer the machine carries its own compressor cylinder; in a steam-air hammer a large central supply of steam or compressed air lifts and drives the ram. Those central-air hammers needed very large volumes of air at moderate pressure and were among the biggest air users in any plant.
Today most production forging uses mechanical crank presses, screw presses, hydraulic presses and hydraulic or electro-hydraulic hammers, which are more controllable and efficient. Compressed air has not disappeared. It now does the support work that keeps a press line running: clutch and brake operation, die cooling and blow-off, lubricant atomisation, scale removal, part transfer, shot blasting and maintenance tools. Small self-contained pneumatic hammers are still used in jobbing shops and for open-die work.
Where compressed air is used in a forging plant
| User | Typical pressure | Flow pattern | Air quality (ISO 8573-1, typical) |
|---|---|---|---|
| Mechanical press clutch and brake, counterbalance | 5–6 bar, set by press maker | Every stroke, critical | Dry, filtered air; lubricated only if maker specifies |
| Die blow-off (scale and debris) | 5–7 bar | Short blasts every cycle | General dried air |
| Die lubricant spraying (graphite or water-based) | 3–6 bar at spray head | Cyclic, synchronised with press | Clean, dry air for consistent atomisation |
| Die cooling air jets | 4–6 bar | Frequent or continuous | General dried air; large potential waste |
| Billet and part handling, pick-and-place, ejectors | 6 bar | Rapid cylinders | Dried, filtered air |
| Induction heater loaders, gates and pushers | 6 bar | Intermittent | Dried plant air |
| Shot blasting machines (valves, cleaning, airblast types) | 6–7 bar | Steady for airblast; low for wheel types | Dry air; aftercooler and separator |
| Trimming press clutch, conveyors, sorting gates | 5–6 bar | Intermittent | Dried plant air |
| Grinders, chippers and maintenance air tools | 6.2 bar (89.9 psig) at tool | Intermittent bursts | General air with filter-regulator |
| Self-contained pneumatic hammer (jobbing shops) | Own internal compressor | Not from plant air | Not applicable |
Treat these as typical. Press clutch and brake pressures in particular must follow the press maker’s setting; a wrong pressure affects stopping performance and safety.
Die blowing and lubricant spray: the biggest hidden air user
In closed-die forging, the die is cleaned of scale and sprayed with lubricant on every stroke. On automatic lines this is done by spray manifolds or robots; on manual lines by an operator with a spray lance. Open blow-off nozzles that run continuously, or that are left open between strokes, can account for a large share of a forge’s compressed air.
- Use timed blow-off synchronised with the press stroke instead of continuous blowing.
- Fit engineered nozzles and regulate blow-off pressure to what removes scale, not full line pressure.
- Keep spray air clean and dry; water and oil in air change droplet size and cause uneven lubricant films, die sticking and short die life.
- Check whether die cooling can be done with lower-pressure air from a blower; see air jets and blow-off alternatives and blowers vs compressors.
- Measure the demand of one press line before and after changes; it shows the value quickly.
Shot blasting and handling
Most forgings are shot blasted to remove scale before machining or inspection. Wheel-type (centrifugal) shot blast machines use little compressed air, mostly for valves, doors and dust-collector pulse cleaning. Airblast cabinets and nozzles use a great deal: each nozzle needs a steady, high flow at 6–7 bar for as long as it runs, and moist air causes shot clumping and flow problems.
Size the compressor for the number of nozzles that run together and the nozzle bore, and fit an aftercooler, moisture separator and drain close to the blast equipment. See abrasive blasting nozzle and air supply. Handling systems, from billet loaders to robots, need consistent pressure more than large volume; local receivers near fast-cycling cells stop pressure dips from upsetting them.
Typical system architecture
A medium forging plant typically runs two to five rotary screw compressors with a common header, refrigerated dryers and filtration. Because forging is hot and dirty, the compressor house design matters as much as compressor choice.
- Locate the compressor room away from furnaces, induction heaters and shot blast dust, with cool, filtered intake air.
- Provide ducted ventilation; compressors in a hot forge bay lose capacity and trip on high temperature.
- Fit a wet receiver and refrigerated dryer sized for summer conditions, followed by general and coalescing filters.
- Run a ring main around the press lines with drop legs from the top and drains at low points.
- Add local receivers near presses with large blow-off and near airblast equipment.
- Keep standby capacity: if the largest compressor stops, the remaining machines should still cover clutch, brake and handling air.
- Use sequencing or a central controller to avoid several part-loaded machines; see controls and sequencing.
Air treatment in a hot, dusty plant
Forge shops have high ambient temperatures near presses and furnaces, scale dust, graphite and oil mist. Intake filters and coolers on compressors block quickly, raising discharge temperatures; oil-injected screw compressors normally run with discharge temperatures of about 75–95 °C and trip if cooling fails.
A refrigerated dryer giving a pressure dew point of about +3 °C is usually enough for plant air. Press clutch and brake valves and proportional spray valves benefit from good filtration and reliable drains. Where compressed-air lines run near furnaces and then into cooler areas, extra drainage prevents water slugs. See aftercooling and condensate removal.
Reliability and standby cover
Loss of air stops press clutches and brakes, handling and lubrication at once, so a forge line goes down within minutes. Billets in the furnace may be wasted and dies cool and need reheating. Plan for this:
- N+1 compressor capacity on the main header.
- Dryer bypass with filtration for short emergencies.
- Critical spares for the installed compressors kept on site.
- Planned preventive maintenance; see preventive maintenance.
- A pre-agreed rental arrangement and tie-in point for a temporary compressor during breakdowns or shutdowns; see temporary air for planned shutdowns.
Indian context: auto component forging
India has a large forging sector, much of it serving the automotive and tractor industry with crankshafts, connecting rods, gears, axle parts and hand tools. Major forging clusters are found in Maharashtra, Tamil Nadu, Punjab, Haryana and Karnataka, with forging, machining and fabrication units in industrial estates around Hyderabad and in Andhra Pradesh serving automotive, defence, railway and engineering customers.
Common conditions include high summer ambient temperatures, heavy dust, voltage fluctuations that affect motors and drives, and many plants with a mix of old and new presses. That mix often means a compressed-air system that has grown piece by piece, with several makes of compressor and no central control, which is exactly where an audit pays off.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Compressors tripping on high temperature | Hot room, dust-blocked cooler, poor intake | Clean coolers; ducted intake and exhaust; relocate if needed |
| Press clutch slipping or slow brake | Low or unstable air pressure, wet air in valve | Local receiver; check regulator setting and dryer |
| Uneven die lubrication, sticking | Water or oil in spray air, pressure fluctuation | Improve drying and filtration; regulate spray pressure |
| Shot clumping in airblast | Moist air | Aftercooler, separator and dryer near blast unit |
| High power use | Continuous blow-off, leaks, raised pressure | Timed blow-off, leak survey, pressure reduction |
| Frequent motor failures | Voltage dips, dust in motor | Phase protection; clean or ducted cooling |
How Reddy Compressors helps
Reddy Compressors serves forging plants as an independent multi-brand specialist. We sell new rotary screw and piston compressors, used and refurbished machines, dryers, filters and receivers; we service and overhaul ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic and other makes under call-out or AMC; and we carry out air audits, leak surveys and demand logging on press lines.
For breakdowns and shutdowns we rent electric and diesel compressors from our own fleet, 50–2,000 cfm and 2–30 bar. For long-term projects we can supply brand-new compressors to site. Spare parts are identified from the nameplate and fit is confirmed before quoting.
Our only office is at Srinilayam, 12-13-200, First Floor, Street No. 1, Tarnaka, Secunderabad 500017. Call +91 99590 60718 or +91 92468 88812, WhatsApp +91 99590 60718, or email reddycompressors@gmail.com. Service teams cover the whole of Telangana and Andhra Pradesh, and we supply equipment, rentals and spare parts across India.
Our track record. We have supplied compressors to leading companies in forging across Telangana, Andhra Pradesh and beyond – new and used machines, long-term rental, and breakdown cover when a plant’s own compressor fails – backed by our own service team.
What to send us
- Number and type of presses and hammers, and shot blast equipment
- Existing compressors, dryers, header pressure and any logged data
- Blow-off and lubricant spray method on each line
- Compressor room conditions: temperature, dust, ventilation
- Location of the site and whether it is in Telangana, Andhra Pradesh or elsewhere in India
- Nameplate photos of existing compressors, dryers and receivers (make, model, serial number)
- Contact name and phone or WhatsApp number for a site visit, on +91 99590 60718 or +91 92468 88812
Frequently asked questions
How is compressed air used in a forging plant?
In most modern forges compressed air operates press clutches and brakes, blows scale off dies, atomises die lubricant, cools dies, drives part handling and ejectors, and supplies shot blasting and maintenance tools. It is usually supplied at 6–7 bar by rotary screw compressors with refrigerated dryers. Hammers themselves are now mostly mechanical or hydraulic.
Are pneumatic forging hammers still used?
Yes, but mainly as small self-contained pneumatic hammers in jobbing shops and for open-die work. These machines carry their own compressor cylinder and do not draw on plant air. Large central-air or steam-air drop hammers have largely been replaced in production forging by mechanical presses, screw presses and hydraulic or electro-hydraulic hammers.
Why does my forge compressor keep tripping on high temperature?
Forge shops are hot and dusty, so coolers and intake filters block quickly and room air is often too hot. An oil-injected screw compressor typically runs at about 75–95 °C discharge temperature and trips when cooling fails. Clean coolers and filters, check oil level and grade, and provide ducted cool intake and exhaust air.
How can a forging plant reduce compressed-air cost?
Start with die blow-off and cooling jets, which often run continuously. Synchronise blow-off with the press stroke, regulate nozzle pressure and fit engineered nozzles. Then repair leaks, lower header pressure where possible, since each extra bar costs about 7% more power, and use sequencing so compressors are not all running part-loaded.
What air quality does die lubricant spraying need?
Spray air should be clean, dry and at stable pressure so that lubricant atomises consistently and forms an even film. Water or oil in the air changes droplet size, causes patchy coating and can shorten die life. A refrigerated dryer at about +3 °C pressure dew point with good filtration and drains is usually adequate; follow the spray system maker’s requirement.
Can you supply a temporary compressor if our forge compressor breaks down?
Yes. We rent electric and diesel compressors from our own fleet, 50–2,000 cfm and 2–30 bar, and can include hoses and site support. Agreeing the pressure, flow and a tie-in point in advance makes changeover quicker. We serve forging plants across Telangana and Andhra Pradesh, and supply rentals and spares across India.
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Technical content reviewed by D. Srinivas Reddy, Managing Partner and service engineer, Reddy Compressors. Last updated 21 October 2026. How our engineering content is reviewed.