Safety in blow-moulding

The DFEn system, developed by Bosch Rexroth, has recently been installed on a dual-closure accumulator-head blow-moulding machine built by Uniloy Milacron (Magenta, Milan, Italy) to improve safety and energy efficiency. The system achieves the objective of a Category 3, Performance Level "e" safety rating per EN ISO 13849, while providing a hydraulic plant that ensures significant energy savings.
The design includes a servo-controlled axial-piston variable-displacement pump with closed circuit pressure and flowrate control. Thanks to a new version of the proportional pilot valve, the pump communicates with an inverter that controls a servo-ventilated asynchronous electric motor which, in turn, ensures optimal rotation speed for every phase in the machine cycle.