Energy-Efficiency Improvement and Processing Performance Optimization of Forging Hydraulic Presses Based on an Energy-Saving Buffer System

This paper proposes an energy-saving system based on a prefill system and a buffer system to improve the energy efficiency and the processing performance of hydraulic presses. Saving energy by integrating such systems into the cooling system of a hydraulic press has not been previously reported. A prefill system, powered by the power unit of the cooling system, is used to supply power simultaneously with the traditional power unit during the pressurization stage, thus reducing the usage of pumps and installed power of the hydraulic press. In contrast to the traditional prefill system, the proposed energy-saving system is controlled by a servo valve to adjust flow according to the load profile. In addition, a buffer system is employed to the cooling system to absorb the hydraulic shock generated at the unloading stage, store those shares of hydraulic energy as a recovery accumulator, and then release this energy to power the prefill system and the hydraulic actuator in the subsequent productive process. Finally, through a series of comparative experiments, it was preliminarily validated that the proposed system could reduce the installed power and pressure shock by up to 22.85% and 41%, respectively, increase energy efficiency by up to 26.71%, and provide the same processing characteristics and properties as the traditional hydraulic press.