CHICAGO (Aug. 21, 4:05 p.m. EDT) — Niigata Machine Techno Ltd. touted the extra-long holding pressures on its new MD-X and MD-W lines of all-electric injection molding machines at its NPE 2006 exhibit.
Niigata showed an MD-X with 55 tons of clamping force and a 385-ton, wide-platen MD-W.
Maintaining long holding pressure can overload electric motors, but Niitaga said the MD-X can hold for 60-100 seconds. The MD-W can maintain holding pressure for 70-100 seconds.
Both presses also boast quick servomotor response time of 55 microseconds.
On the MD-W, Niigata has increased the tie-bar spacing by 11 percent and increased the minimum mold height as well.
The MD-X boasts a compact design and injection driven by dual ball screws for better alignment and longer machine life.
Belt-drive machines have other advantages over direct-drive all-electrics, according to Peter Gardner, vice president and general manager of Niigata operations at DJK-Global Ltd. in Itasca, Ill. “To us, the belt-drive system is just simpler to maintain, cheaper to maintain for the customer,” he said. “If there's a problem, replacing a belt is a couple hundred dollars. Replacing a direct-drive gearbox is thousands of dollars.”
Niigata also likes to use comparable drive technology across its range of injection presses. “All the competitors, as they get into the bigger tonnages, they have to go to a belt because the direct drive is just not efficient for that. And because we build from small all the way up to 2,000 tons, we want to keep consistency through the whole line,” Gardner said. “So with belt drive, it's the same design all the way up to 2,000 tons.”
Also at the Niigata booth was a 55-ton MDVR press with vertical clamp and vertical injection, with a two-station rotary table.