CHICAGO (July 10, 11:15 a.m. EDT) — You had to squint to see the 1-millimeter-wide bobbins running on a new 20-ton, all-electric press from Sumitomo Heavy Industries Ltd. To really see details, Sumitomo had a microscope on hand.
Makuta Technics Inc., a micromolder and Sumitomo customer in Columbus, Ind., molded the bobbins on a two-cavity mold during the show. Makuta bought the 20-ton show machine — the first SE18S Sumitomo shown in the United States.
Sumitomo also showed a 253-ton all-electric press, a new screw tip designed specially for the electric machines and an option that dramatically speeds up filling and braking on its toggle-clamp machines — up to a lightning-fast 78.7 inches a second.
Two new sizes of the SHC line of general-purpose machines rounded out Sumitomo´s booth, where eight injection presses were turning out parts at NPE in Chicago.
On the electric side, Sumitomo said both the 20- and 253-ton all-electric machines have a maximum injection speed of 12 inches per second, with a very quick response time. That means SES-series presses are capable of high-speed filling, high-speed decompression and stable molding. Mold open and close speeds are 51.2 inches a second.
The 20-ton electric delivers injection pressures of up to 32,420 pounds per square inch, so it can run narrow-pitch connectors, small thin-wall parts and micromolded components. The 253-ton press at NPE was running eight polypropylene containers on a four-second cycle.
Sumitomo already was making all-electric SES presses in clamping force tonnages of 33, 55, 83, 110, 198, 308 and 385 tons.
On models up to 200 tons, two direct-drive alternating current servo motors power the injection unit. On models larger than 200 tons, Sumitomo uses motors that drive belts.
Sumitomo makes its own servo motors in Japan.
The company also showed a screw tip, the SK, dubbed the SK Control option, for all-electric presses. During the plasticizing process, the screw rotates clockwise, in the traditional manner. This aligns the check ring and seal so the channel is open for the melt to flow forward. Once the shot is recovered and before injection begins, the screw reverses and spins counter-clockwise, automatically locking closed the check ring and shutting off material flow.
Sumitomo said the SK option is well-suited for molding high precision parts such as connectors, lenses, packaging and office automation products.
Not all of Sumitomo´s news at NPE involved electric presses. The company also introduced the HP+ Option for its SGM line of high-speed toggle-clamp presses, for molding jobs that require high injection pressures with very fast filling and braking.
Sumitomo claims that SGM presses equipped with the HP+ Option can produce injection speeds of 78.7 inches a second and injection pressures up to 47,210 psi. The result is a machine than fills about six times faster than a standard press, Sumitomo said.
To boost response time, the company added a digitally controlled servo valve.
Sumitomo is offering the HP+ Option on SGM presses with clamping forces of 110 and 198 tons, with the C170, C220, C450 and C570 plasticizing units, for shot sizes ranging from 1.9 to 6 ounces.
In general-purpose molding machines, Sumitomo has added a 55- and an 88-ton press to its SMC series, which goes up to 385 tons of clamping force. The machines are built at Sumitomo´s factory in Jefferson, Ga.
The company´s U.S. headquarters offices are in Norcross, Ga., at Sumitomo (SHI) Plastics Machinery of America LLC.