All-electric injection-molding machines are said to cut energy consumption by 50 to 90% compared to equivalent hydraulic machines. Electric machines use energy only when cycling, whereas traditional machines continue to consume energy even when "idling."
Additional energy is needed to cool hydraulic oil via an auxiliary chiller or heat exchanger in traditional machines as well. The coolers not only consume energy, but also heat the plant. This leads to either an unbearably hot facility in the summer, or an equally unbearable electric bill for air conditioning.
The motors and controls for allelectric machines must also be cooled, but are said to generate 65 to 75% less heat. Milacron Inc., Batavia, Ohio, estimates that the U.S. could save 9 million MW-hr if all the country's plastic injection-molding machines were replaced with all-electric models. One thousand households consume about 1 MW of electricity annually.
A number of additional "green" benefits can be attributed to allelectric IMMs. First is the conservation of raw materials (resins). IMMs reportedly have better shotto-shot repeatability than their hydraulic counterparts. IMMs are also said to hold 50% tighter tolerances than those of equivalent hydraulic presses. Both properties help eliminate scrap material.
Second, IMMs rid a plant of hydraulic oil which improves cleanliness, safety, and reduces maintenance. And it eliminates costs associated with hazardous waste disposal. Finally, electric IMMs reduce noise levels to less than 70 dB, which reduces operator fatigue and stress.
Milacron Inc., Plastics Technologies Group, 4165 Halfacre Rd., Batavia, OH 45103, (513) 536-2428