Parallel holding system with cutting shock damping
from Lemacher Hydraulik®
With our parallel holding system not only the cutting impact is effectively fought. Our linear synchronised flow divider also drastically improves the parallel holding of upper and lower tools without additional effort. High precision is guaranteed even with eccentric loads in the tool.
Improvement of press performance
Press requirements are becoming more and more demanding. Old hydraulic presses can no longer be used for precise work with new tools. New pressing tools make it necessary to make the presses more stable and to improve the parallelism of upper and lower tools. Even with off-center loads in the die, we can significantly improve the performance of old and new hydraulic presses with our parallel holding system. The loads on man and machine caused by the cutting impact during presses and punching must no longer be part of a hydraulic press, which is why our parallel holding system was also developed as cutting impact damping for presses.
How it works
The basis of this system is our linear synchronised flow divider, which has proven itself in many areas of industry for many years. With the synchronous cylinders, the cutting impact is removed in a controlled manner via a defined oil cushion and a parallel position is created. Depending on the application, it is manufactured with or without an external oil supply. For presses with a low stroke frequency, we recommend units which are equipped with a pressure accumulator and operate independently. In the simplest case this can be done manually without control. However, a connection to the press control is practical. The synchronous cylinders and the linear synchronised flow divider automatically return to their initial position when the press is opened. An oil pressure of 60 bar via an accumulator causes a force of 5kN per cylinder to return to the extended position. The cylinders then wait for the next ram stroke. During the downward movement of the press the parallel holding system works as a displacer. The resulting flow rates can be easily limited. The energy released during the cutting impact increases the volume flow; this increase is absorbed and significantly reduced by the selected components right from the start. The parallelism is also maintained during the cutting stroke. The synchronous cylinders are always designed for the full press force and are thus able to absorb the complete press force even in the fully retracted position (stop).
Im einfachsten Fall kann dies manuell ohne Steuerung geschehen. Praktikabler hierbei ist jedoch ein Anschluss an die Pressensteuerung. Die Gleichgangzylinder und der Linear-Gleichlauf-Mengenteiler fahren beim Öffnen der Presse selbsttätig in ihre Ausgangsposition zurück. Über einen Speicher bewirkt ein Öldruck von 60bar eine Kraft von 5kN pro Zylinder um wieder in die ausgefahrene Stellung zu fahren. Anschließend warten die Zylinder auf den nächsten Stößelhub. Während der Abwärtsbewegung der Presse arbeitet das Parallelhaltesystem als Verdränger.
Die sich ergebenden Durchflussmengen lassen sich einfach begrenzen. Die beim Schnittschlag frei werdende Energie erhöht den Volumenstrom, diese Erhöhung wird schon im Ansatz durch die ausgewählten Komponenten aufgefangen und deutlich reduziert. Hierbei wird die Parallelität auch während des Schnittschlags gehalten. Die Gleichgangzylinder werden immer auf die volle Presskraft ausgelegt und sind somit in der Lage, auch in der voll
eingefahrenen Position (Anschlag) die komplette Presskraft aufzunehmen.
Structure or installation
DThe linear synchronised flow divider and the synchronous cylinders can be designed flexibly and to suit the machine incl. tool, depending on the required size and given possibilities. Normally, the flow divider is placed on the side of the press table and the synchronizing cylinders are placed on the press table in a non-slip manner. To ensure the greatest possible parallelism, the synchronous cylinders are connected to the LGM by tubes of the same length. The synchronous cylinders are manufactured to the highest precision and have the same heights. In order to compensate for mechanical inaccuracies of the machine, there are intermediate plates that can be adapted accordingly. Thus the parallelism of the system can be further improved.
We manufacture our systems ourselves, so that we can ensure a high accuracy of the components. The greatest deviations or tolerances are caused by the compressibility of the fluid used. With hydraulic oil, a volume loss of 0.7% can be assumed with a pressure difference of 100 bar. If a water-glycol mixture is used, this value is halved.
Our product advantages:
- Pure hydraulic system, without electrical regulation
- No failure-prone electrical components
- No time-consuming programming necessary
- Can be operated independently as a separate system
- Asynchronous tool loads are absorbed by the system
- Improvement of the tool life of the press tools
- Improvement of product quality
- Increase in productivity
- Drastic reduction of noise emission
- Reduction of the press load
- Can be retrofitted to all hydraulic presses
- Easy installation and commissioning
- Parallel holding and cutting impact in one
- Low maintenance system