Energy efficiency: out with the new, in with the old

Engel has launched a new retrofit solution designed for use on older manufacturing systems that it says reduces the energy required by exisiting hydraulic injection moulding machines by up to 50 percent.

In response to the industry’s need for cost-efficiency and sustainability, as well as addressing rising energy prices, Engel says it has developed the new ecodriveR as a retrofit solution that is “reasonably priced” and “can be fitted with little hassle” to significantly increase the saving potential of older injection moulding machines to bring them inline with the efficiency capabilities of newer, more modern models.

ecodriveR is the next generation of Engel’s servo-hydraulic drive system, ecodrive. Consisting of a servomotor and a fixed displacement pump, ecodrive saves lost energy among other things. Without an energy saving option, lost energy builds up when a machine is idle and traditionally accounts for a large proportion of its total energy consumption.

Engel says new ecodriveR means hydraulic injection moulding machines with an asynchronous motor and electric-hydraulic variable capacity pumps (EHVs) can now be controlled according to demand as well. This is achieved through the installation of a frequency converter that adjusts the speed of the pump drive to the amount of energy required. ecodriveR is set using a simple interface of the machine control unit, Wolfgang Degwerth, Head of Engel Austria's customer service division, explained.

"Since a machine's hydraulic system remains the same when it is retrofitted, ecodriveR allows us to adapt older injection moulding machines to the requirements of modern production companies quite quickly and at a relatively low cost,” he commented. “The first few uses have shown that, depending on the application, it can reduce the energy required by machines by up to 50 percent without affecting the cycle time, part quality or reproducibility standards.“

As with the original ecodrive principle, Engel says the drives of an injection moulding machine with the retrofitted ecodriveR are only active when the machine is in movement, such as during mould opening and closing, plasticising and injecting. During the post injection pressure and plasticising phases, the speed is reduced, and during cooling, the drives come to a complete standstill and do not use any energy at all.

Engel says the saving potential depends on different factors. Machine size and cycle time play a crucial role among other things. If, for example, POM technical parts with a shot weight of 109 g and a cycle time of 78.3 seconds are made on an Engel victory 330/125 injection moulding machine that has been energetically optimised with the ecodriveR system, 3.7 kWh of energy will be saved every hour, which Engel explained means 46 percent less will be consumed compared to a machine that has not been updated. The 3.2 kWh/h drive energy reduction and the fact that the cooling/filter motor uses 0.5 kWh/h less energy make a major contribution here, it said. If the machine is in operation for 6000 hours per year, the amount of electricity it uses will be cut by 22,200 kWh overall, which equates to six tonnes of carbon dioxide.  

The retrofit option ecodriveR can be added to any ENGEL hydraulic injection moulding machine with three or fewer asynchronous motors and electro-hydraulic variable capacity pumps.