A power press is a machine that drives a ram, or slide, down onto a die to cut, punch, bend or form sheet metal. Indian makers, including many in Rajkot, build mechanical and hydraulic presses from small bench presses to large machines for heavy forming.
Tonnage is the maximum force the press can apply. You choose it from the force your tooling needs, plus a safety margin, not from the largest number on offer.
Common press types
- C-frame or open-front presses give access from three sides and suit small blanking and piercing work.
- Straight-side or H-frame presses resist deflection better and suit heavier and more precise work.
- Pillar-type hydraulic presses suit deep drawing, forming and assembly tasks.
- Pneumatic presses suit light assembly, riveting and marking work.
- Press brakes are long presses used for bending sheet metal.
How to choose the tonnage
For blanking and piercing, the force depends on the cut perimeter, the sheet thickness and the material's shear strength. Your toolmaker should calculate it from the part drawing. Then add a margin, because blunt tools and harder material raise the load.
For a mechanical press, the rated tonnage is only available near the bottom of the stroke. If your work needs high force higher in the stroke, as deep drawing does, a hydraulic press may suit better. Our article on mechanical and hydraulic presses explains the difference.
Do not size on tonnage alone. Check the bed area, shut height, stroke length, strokes per minute and the daylight opening. The die must fit, and the press must run at the speed your output needs.
What decides build quality
- The frame should be welded steel plate or a heavy casting, stress-relieved so it does not distort under load.
- The clutch and brake on a mechanical press should be a type suitable for the safety controls your country requires.
- The slide guides should be long and adjustable, so the die stays aligned and tools last longer.
- Overload protection, such as a hydraulic overload system, protects the press and the die from a jammed stroke.
Safety comes with the press
Presses are among the most dangerous machines in a workshop. Many low-cost presses are sold without the guards, light curtains and safety controls that your country requires. That is a legal risk as well as a safety risk.
Before ordering, read what safety guards presses need for export and agree the safety package in the contract. In most countries the importer or employer carries legal duties, so confirm the rules with your regulator. A safety package fitted at the factory and tested during the trial is far easier than retrofitting guards after delivery.
Next step
Send your part drawings and output target, and we will shortlist press makers with the right size and safety package. To start, book a free sourcing review.