SERVO Hydraulic Production Press

Design
By combining the quality of our conventional hydraulic production press and replacing the control valves of the hydraulic systems with a servo motor, speed, position and press force are controlled merely electrically. The simple design reduces the number of parts and stabilises oil temperature while facilitating availability and repeat accuracy. Finally the simple design minimises maintenance costs and frequency.

Speed
Integrating the force of speed with a servo-motor solution enables extremely fast acceleration and deceleration measured up to 3 times faster than a conventional hydraulic press. The high speed facilitates not only significantly shorter cycle times, yet also improves process control and overall performance stability.

Energy savings up to 70%
Facilitating high speed and extremely short cycle times, the servo-motor solution distinguishes itself by reducing energy consumption with up to 70%, depending on the application.

High energy savings are achieved primarily by:

• Regenerates fall-energy from ram approach
• Main motor stop for every completed stroke (no idling)
• No energy loss by deep drawing with passive cushion (single acting die cushion)
• Reduced cooling of the hydraulics

Well Tested Technology
While the SERVO-hydraulic press is a new product to STENHOJ, the high-quality components and combined technologies deployed, are familiar and well tested.

Thus, underpinning the new SERVO-hydraulic press technology, we use the same quality parts, components and electrical cabinets as for our well known hydraulic presses, while the construction of the hydraulic system still offers the same options for pressure control as our conventional hydraulic press.

Finally, we have deployed decades of experience with advanced pump systems and expertise from more than 150 advanced electro-mechanical broaching machines with equivalent servo-motor system to the design of the press.

By combining the best of two worlds the SERVO-hydraulic press from STENHOJ is a strong and competitive choice for modern production.

A significant feature of the SERVO-Hydraulic Press is its impressive speed.
By using a servo motor as driving force, acceleration and deceleration speed increases significantly compared to a conventional hydraulic press. The high speed of the press and fully programmable die cushion (speed, force and position), enables extremely short cycle times.

Pressing Speeds (typical)
Approach speed: 0-500 mm/s, adjustable in program and controlled by servo motor
Return speed: 0-500 mm/s, adjustable in program and controlled by servo motor
Pressing speed: 0-50 mm/s, adjustable in program and controlled by servo motor .

Efficient operation conditions:

• More than 30 strokes/min.
• 0-100% return speed in 0.1 s (conventional +0.5 s)
• Rapid Speed >500 mm/s – approach and return
• Rapid acceleration and de-acceleration of ram
• Full press force over the entire stroke
• Single- and double acting die cushion
• High position accuracy on ram
• Fully programable ram and die cushion
• Adjustable approach and return speed  ->

• • Energy optimization
  • Trimming of cycle time
  • Factory acceptance

The user friendly control system is built to meet latest European safety regulations.
In accordance with the safety regulations, the hydraulic system has dual monitored safety valves, monitored by a safety PLC.

The various press functions of the press are set directly on the control cabinet and displayed on the HMI touch panel.

Operator Panel  1, 2, 3 axes or more
Based on a Siemens PLC and a 9-, 12- or 15-inch Siemens touch panel.
The control consists of a freely programmable interface with up to 54 program lines to build a press program.
The user can use the program lines to control the axes of the press and 8 I/O’s, dependent or independent of each other in a desired sequence.

The following features can be selected in each program line directly on the operator panel:

• Signal exchange between individual axes and I/O
• Position control, speed control and pressure setting.
• Progressive or degressive pressure or speed regulation within a given press process.
• Dwell time in bottom ram position (timer function)
• Decompression time at ram return start (timer function)
• Stroke- and working hour counter
• Memory for 1 up to 500 programs.
• Error message from the PLC

Operation modes, on lockable electric selector switch 

• Inching (tool setting)
• Two-hand operation
• Single & double break light guards
• Foot operation (optional)
• Automatic operation

Light Guard
Using a light guard during insertion work allows safe operation without having to activate the normal operating push buttons. This works in a single or double break operation. Additional protection function against unauthorised access.

Integration Options
Possibility of signal exchange with external equipment, such as feeder, robot or transfer system.

Industry 4.0
The STENHOJ SERVO-hydraulic press not only meets energy goals of contemporary sustainable production. It also secures product quality and increased productivity with the integration of advanced sensors and actuator intelligence for data collection enabling OEE optimisation and predictive maintenance.

On request, wear, tool or service life monitoring can be integrated.

The hydraulic power pack is located at the rear top of the press and is easily accessible and service friendly.

All our pump systems are designed to fit each press size to achieve low energy consumption and avoid excessive heat in the hydraulic system.

The Main axis, die cushion and ejector can work independently at the same time.

The pumps are submerged directly into the oil tank, securing low noise.

The main valve system is placed on the hydraulic tank and designed in compliance with European safety requirements to meet the CE-standard.

The well dimensioned Bed- and Ram plate is equipped with T-slots for clamping and support of the press tool.
We offer customised Bed plates and Ram plates dimensions with desired holes and T-slots

Ram plate guiding specifications
In addition to the high guiding accuracy of the cylinder and depending on the working task requirements, STENHØJ Hydraulik offers five guiding types for the Ram suitable for the pressing process.

Type 1 and 2: The Ram plate is guided by 2 or 4 columns through guides with self-lubricating bronze bushings from above. In order to ensure a stabilised construction, the columns are integrated into the Ram/slide plate.

Type 3 and 4: The Ram guide consists of four strong columns integrated in the frame leading the ram/slide plate trough self-lubricated guides. The choice between a ram plate or a ram in a welded box depends on the tool width and the tool support requirements.

Type 5: The Ram/slide is a Box design and guided by means of eight (8) pieces 90° guide shoes equipped with replaceable PTFE compound inserts for minimum friction and long life. These gibs allow for extraordinarily high loads. Replaceable, hardened, and grinded guideways are bolted onto the press frame.

Type 3-5 are commonly used when high accuracy and high guiding stability for long strokes and eccentric side load are required.

We design all our cylinders in-house.

Exact guiding and good seal components are important for press cylinders.
Over the years, STENHØJ has developed and standardised our cylinders with long guides, to obtain an accurate and strong piston guide.
For this purpose, we use high quality, expertly processed steel pipes with a cylinder surface which are either roller polished or honed for achieving a smooth and durable surface, together with a grinded and hard chromed piston rod.

The guide bushes are made of our special material that provides a strong and precise guide along with our reliable wear-resistant and tight sealing elements guarantee the cylinders a long service life.

The ram/slide lock is designed for mechanical parking of the Ram/slide during the tool change etc.

The ram lock is connected to the safety PLC system, when the operator needs to park the ram.

By pushing a button, the ram/slide will automatically return to top position and lock the ram/slide, and the hydraulic power unit will turn off.

The STENHOJ SERVO-hydraulic Press is designed to comply with all European safety standards including the harmonised standards for presses:

DS_EN ISO 16092-1_2018 & DS_EN ISO 16092-3_2018.