CHICAGO (Aug. 1, 4:30 p.m. EDT) — At NPE 2006, JSW Plastics Machinery Inc. molded a super-thin polycarbonate part on a super-fast injection speed of 800 millimeters per second.
``We´ve gone to ultra, ultrahigh speed,´´ said Brian Sams, business development manager, at JSW´s booth.
The Elk Grove Village, Ill.-based company also demonstrated in-mold labeling and an injection/compression process to mold a precision gear. All three booth machines were all-electrics.
The thin-wall PC part is a light-guide plate for a cell phone, the flat rectangular component behind the LCD screen that disperses the light onto the screen. Its wall thickness is 0.4mm.
A press, with 60 tons of clamping force, was equipped with JSW´s ultrahigh-speed injection feature. It sounded like a muffled shotgun blast when it injected the PC resin into the mold, making two light-guide screens at a time.
Beyond the lightening-fast injection speeds, JSW boasted some other impressive speed statistics for the J55AD-60H-US: fill time of just 0.04 second on the part, and an acceleration from zero to 800mm per second in just 36 milliseconds.
``We´re using an ultrahigh-speed injection unit with dual servomotors on injection, and with a high pitch on the ball screw for faster linear travel, per revolution on the ball screw,´´ Sams said. Higher pitch means the flights are at a steeper pitch. The two servomotors give the necessary horsepower, through the belt-and-ball-screw system.
Sams said the machine is very precise, which is required for the thin, flat light-guide. ``Our range of variance, across 18 points on the part, is less than one-hundredth of a millimeter,´´ he said.
In the other molding demonstrations, JSW:
* Molded an acetal gear on a 121-ton press, model J11OAD-180H. The mold gets filled out under full tonnage, and then the press uses its ejector pins to push against the part, giving it an extra fill-out force at the late stage of fill. This ``partial compression´´ using the ejectors, improves accuracy, according to JSW.
* Produced polypropylene yogurt cups, in a four-cavity mold and via in-mold labeling, on a four-second cycle. An electrostatic charge was holding the label in place. The press, a J180AD-300H, has 200 tons of clamping force.
In other news, JSW officials announced - but did not show at NPE - that the company has stepped up to larger sizes of all-electric injection molding machines. Last year, Japanese parent company Japan Steel Works built a 1,980-ton all-electric injection press.
JSW now has officially cracked the 2,000-ton barrier, said Robert Columbus, head of marketing and regional sales manager. ``We´re delivering our first and largest 2,750-ton all-electric,´´ Columbus said.