For large machining centers, hydraulic weight balancing of spindle heads and/or work piece tables pays off. Because HAWE Hydraulik’s cleverly arranged systems cut down the processing center’s consumption of electricity and resources. They contribute not only toward energy efficiency in production, but also lower the machines total costs of ownership (TOC). What’s more, when hydraulically counterbalanced, the motors for the vertical axes of spindle head and work piece table can be dimensioned significantly smaller, which provides for more dynamic movements of the axes and generates additional savings in electricity.
Hydraulic weight balancing is an autonomous system. Once it has been pressurized it requires no further energy intake. A hydraulic cylinder that is connected with the hydraulic accumulator takes up the weight of the spindle head and/or work piece table. The pressure in the system is set so that the cylinder balances out the weight. Merely the force of friction and the inertia of masses must be overcome to move the spindle head along the vertical axis. This in turn requires significantly lower drive power.
The power pack supplying pressurized oil is only needed when filling the system ahead of start-up and in case of maintenance. As these two instances are not time-critical the power pack’s capacity can be smaller. One suitable solution could be HAWE’s compact MPN power pack. It meets the criteria of providing high operating pressure with small capacity, has a compact built and a large tank volume for filling and emptying the system.
It requires a pressure reducing valve for the supply of the pressurized oil, so that the required operating pressure is set while filling the system. During operations a pressure switch monitors the system’s pressure, signaling any under- or overshooting of the predefined pressure range. The machine operator will then undertake the corresponding actions, i.e. check the system for leakages or control the accumulator’s preload pressure. A pressure valve secures the hydraulic accumulator, while a drain valve is used to empty the storage for maintenance work. The compact valve bank, BA type, contains all these standard components, so that pipe works and assembly of a separate block construction is omitted.
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