Hydraulic Press Limitations

• Introduction
• Hydraulic Presses - Fast, Reliable, Productive, and Flexible
• 10 Advantages of Hydraulic Presses
• Glossary
• Formulas and Data
• Selecting a Hydraulic Press
• Hydraulic Press Limitations

1. Speed. There are no hydraulic presses today that are as fast as the fastest mechanical presses. If speed is the sole requirement and the material feed stroke is relatively short, the mechanical press remains the best selection.

    

2. Stroke depth. If a limit switch is used to determine the bottom, the stroke depth is not likely to be controlled much closer than .020".

   Many hydraulic presses can be set to reverse at a preselected pressure, which usually results in uniform parts.

   Generally, if absolute stroke depth accuracy is required, "kiss" blocks must be provided in the tooling.

   However, Greenerd hydraulic presses are now available with an accurate built-in method of limiting the down stroke. Greenerd's new closed-loop servo-hydraulic system dramatically improves stroke depth control, guaranteeing consistent, repeatable results. In many applications, this system eliminates the need for "kiss" blocks.

    

3. Automatic feeding equipment. Hydraulic presses require some external or auxiliary power to feed stock. The feeder must have its own power, and must be integrated with the press control system.

   There is, however, an increasing selection of self-powered feeding systems available: roll feeds, hitch feeds, and air feeds.

    

4. Shock after breakthrough in blanking. Both mechanical and hydraulic presses experience this problem. But, the hydraulic system of a hydraulic press must also be isolated from the shock associated with decompression. If the hydraulic system does not contain an antishock feature, this shock can affect the lines and fittings.