Types of Power Presses: By Drive, by Frame, by Job

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Why Press Types Are Confused

Ask five suppliers for a "power press" and you will be quoted five different machines: a 25-ton gap frame crank press, a 3,150 kN hydraulic press, a servo press and a knuckle joint high-speed press all answer to the same name, because a power press is simply a machine that drives a slide (ram) with stored or generated energy to work metal in a die. The useful way to sort them is the way this manufacturer's catalogue is organised: by drive (what moves the slide), by frame (what holds the load), and by job (what the combination is for). This guide walks through all three, anchored to real series and their published data, so the vocabulary survives contact with an actual quotation.

Types by Drive

Mechanical crank presses

The flywheel stores energy; the clutch engages it; the crank and connecting rod convert rotation into the slide's stroke. Crank presses are the layout this catalogue documents most widely: fast and repeatable in operation. Their defining limit is the force curve — full rated tonnage is only available near bottom dead centre, at the rated tonnage point stated in each model's table (1-13 mm above BDC across this range). In this catalogue: the C1N, A1, C1S and C2N gap frame series and the D1N, D2N, M1N straight side series, 15-800 tons, plus two structural variants below.

Eccentric gear presses

The eccentric-gear variant in this range is the S2N straight side eccentric press, documented for work requiring longer stroke lengths: it runs 400-1,600 tons with strokes of 500-700 mm at 12-30 SPM (the range spans the S2N-1600's second SPM option, a presumed restoration of a cell the manufacturer's table prints as a date) and four pressure points — the machine documented for the largest progressive and transfer dies. The T2N two-point straight side press (400-1,200 tons) runs strokes of 300-450 mm.

Knuckle joint presses

A toggle (knuckle joint) linkage drives the slide. In this catalogue the GT series built on it is documented for lead frames and EV motor laminations. The GT series publishes 150-1,500 kN and up to 1,800 SPM — 2,000 SPM on the GT-15H, its smallest model — with a documented die regrinding interval more than 25% longer than a conventional crank press.

Servo presses

A servo motor drives the slide directly, so the motion profile is set in software rather than by crank geometry. The EC1 C-frame (25-315 t) page documents the pendulum curve combined with a progressive die, with energy savings of over 50% claimed against a conventional press; the EM2 straight side (110-630 t) page documents a virtually unlimited number of stroke and slide movement profiles, with full working energy even at slow speeds. Servo is the answer when the part's forming curve — not the press's — should dictate the motion.

Hydraulic presses

A hydraulic cylinder drives the slide at low speed, with stroke and pressure both adjustable — here, two switchable processes: fixed stroke and fixed pressure. Speeds are published in each drive's own units: descent at 300 mm/s and working speeds of 15-80 mm/s on the Y1P and Y1C tables, strokes per minute on the crank tables — the two sets of figures describe different motions and are not converted into a single speed ranking. The Y1P pillar, Y1C C-frame and Y1H H-frame series cover 200-16,000 kN for drawing, forming, powder pressing, correction and pressing. The dedicated comparison is the mechanical vs hydraulic press guide.

Types by Frame

• C-frame (gap frame) — open on three sides; 15-400 tons in the crank range (C1N), plus servo (EC1), hydraulic (Y1C) and high-speed (GS) versions. Deflects under off-centre load; throat depth is its key dimension (C1S deep throat: to 1,300 mm).
• Straight side (H-frame / D-frame) — closed welded box; single crank (D1N, M1N), two-point (D2N, T2N) and four-point eccentric (S2N) drives; bolsters to 6,000 x 1,800 mm.
• Four-post (pillar) — the hydraulic Y1P's three-beam four-post construction guides the moving platen on four columns; the general-purpose hydraulic layout.
• High-speed frames — GHD, GP and GPH H-frames and the GS C-frame run at 60-1,000 SPM (the 2,000 SPM figure in this range is the GT-15H's).

Types by Job

Finally, presses are sold by the job they anchor: punch presses for blanking, punching, bending and forming of thin plate (the application wording of the C1N and A1 pages); stamping presses as the general production term, specified through the selection method on the stamping press page; high-speed presses for laminations, terminals and lead frames; drawing/forming presses (hydraulic and servo) where the work happens through the stroke rather than at its end; and press lines — press plus coil feeding line plus transfer or progressive die — bought as one system, as on the metal stamping machines page. The type names overlap because they answer different questions; a single machine can be a straight side, two-point, mechanical stamping press all at once, and a good enquiry says so.

Frequently Asked Questions

What is the most common type of power press?

The mechanical crank press — gap frame for small and medium work, straight side for long dies and heavy tonnage. It is the layout documented most widely across this catalogue; whether a given series fits a job is read from its published force curve and tables.

How is force published for each press type?

Differently. Hydraulic tables publish a nominal force, read under their fixed-stroke and fixed-pressure processes. Crank and servo tables publish the point in the stroke where full force is available: the rated tonnage point on crank models, and a nominal pressure stroke of 1.5-6 mm on the EC1 and 4-8 mm on the EM2 — the EM2 also documented for full working energy even at slow speeds.

What type of press stamps motor laminations?

A high-speed press built for it — here the GP series (85-550 t, 60-500 SPM), documented for stacked stator and rotor cores. See the lamination guide.

Is a punch press a different machine from a stamping press?

Not in construction: "punch press" names the application (blanking, punching, forming of thin plate), "stamping press" the general production machine. The same C1N is both, depending on the sentence.