Frequently asked questions
The questions we hear most when buying a hydraulic press: daylight vs stroke, C-frame vs H-frame, tonnage sizing and what drives the price.
What is daylight, and how does it differ from stroke?
Daylight is the gap left between the two bolsters when the ram is at the top; stroke is the distance the ram travels. Your die has to FIT into the daylight, while your part has to be FORMED within the stroke. The stroke is always smaller than the daylight and the two cannot be used in place of each other.
Hydraulic press or eccentric (mechanical) press?
An eccentric press is fast and, on short-stroke, high-volume cutting/piercing work, superior in terms of cycle time. The strength of the hydraulic press is control: the nominal force can be obtained at any desired point of the stroke, the speed and the blank holder force can be set to suit the part, and the stroke can be stopped wherever wanted. Deep drawing, hot moulding, composite and sizing work call for that control, which is why they are done hydraulically.
How do you determine the tonnage of the press?
Tonnage is not picked from a catalogue; it is worked out by calculating the material and the thickness of the part, the area being formed and the type of process. The same part calls for one force in deep drawing and another in cutting. If you share your part drawing and your process details, the technical quotation is prepared together with the tonnage, bolster size and stroke figures.
Column-type (pillar) or monoblock?
In the column-type structure the ram is guided on the cylindrical columns at the corners; because all four sides of the machine stay open, feeding, robots and die changes are easy. In the monoblock structure the welded one-piece frame both carries and guides, and it is more rigid at high tonnage. The choice is made according to the tonnage, the die size and the need for automation.
What is the cushion (ejector) for — does every press need one?
No. A cushion is needed in deep drawing to restrain the flow of the sheet into the die (to prevent wrinkling) or to push the finished part up out of the die. It is not needed in cutting, coining and simple forming work. If your process draws sheet metal, whether the cushion force is adjustable determines the result.
Why are there no figures for some presses in the technical tables?
Because those presses are sized to the project and we do not want to publish an unverified figure. Since the bolster size, the stroke and the tonnage change with the part, giving a single “catalogue value” would be misleading. Where we do give figures, we also state that this is an example configuration.
What is the difference between a C-frame and an H-frame hydraulic press?
In a C-frame press the body traces a C in side view; the front and both sides are open, die access is easy and it is economical at mid tonnages. An H-frame (double-upright) press carries the force symmetrically in a closed frame; with less deflection it scales to high tonnages. In ÖZKOÇ naming the closed welded body is monoblock and the column-guided design column-type (pin-guided); the choice follows part size, die access and automation needs.
What determines the price of a hydraulic press?
There is no list price; the press is sized to your part. The main cost drivers are pressing force (tonnage), bolster size and stroke, additional axes such as the cushion / ejector, heating, automation and safety equipment. Share the part drawing and the annual quantity, and the technical quotation is prepared with exactly these items.