Larger Size of Hybrid Electric Machine

A 2200-ton model has joined the em series of two-platen machines with hybrid electric-hydraulic clamp from MHI Injection Molding Machinery Inc., Bensenville, Ill.

A 2200-ton model has joined the em series of two-platen machines with hybrid electric-hydraulic clamp from MHI Injection Molding Machinery Inc., Bensenville, Ill. The new press is expected to come to market in 2006 and fills out a line from 720 to 3300 tons. The em series features electric motor driven plastication, injection and ejection. A split-nut hydromechanical locking system is used on the platen, which is moved by a servo-driven ballscrew mechanism. Clamping pressure is applied by four hydraulic “pancake” cylinders on the tiebars. Compared with a fully hydraulic unit of similar size, the em series is about 15% more compact, has clamp movement that is 30% faster, and a clamp stop position accuracy of 0.0012 in. versus 0.039 in. for hydraulic.