SHANGHAI (May 4, 2:45 p.m. ET) — Arburg GmbH + Co. KG has developed a hydraulic compression molding machine designed to for a 0.5-millimeter-thick optical application.
The machine and application was debuted in Shanghai at Chinaplas 2012. To mold the light guide panels, a thin optical panel intended for use in tablets and thin film transistor (TFT) screens using light-emitting diode lighting, the mold does not close completely.
“These panels have a flow path/wall thickness ration of 350-to-1,” said Jan Lachhein, group leader for application testing at Lossburg, Germany-based Arburg. “This is why regular injection molding won't work.”
The hydraulic Allrounder 630 S has a clamping force of 250 metric tons and operates with a two-cavity mold. It maintains a 1mm gap until the last 50 milliseconds of the process. The mold, in turn, must be designed so that the cavity is sealed, even in the partially open state. This process helps reduce shrinkage and deformation and can accommodate precise molding specifications.
The light-guide panel features nearly imperceptible ridging and changes in thickness at the edges that are designed to “guide” LED light from the edges of the panel. Most tablet panels are lit from behind, explained Lachhein, but the light guide panel can be lit from the edges and maintain even brightness across the entire surface of the panel. Production of the panels is about to be rolled out in Taiwan, and a local mold maker that Arburg declined to identify signed a contract for another machine during Chinaplas, held April 18-21 in Shanghai.
“We have long-term experience in the optical disc business,” said Lachhein. “At the beginning of 2000 the optical disc business died, but the experience is relevant.
“This is basically a DVD, but the shape is different.”
At Chinaplas, Arburg also introduced their new Edrive Allrounder for the first time in Asia. These all-electric machines offer an energy-saving alternative to basic hydraulic machines.
Arburg also showcased its Allrounder 570 H as a representative of the Hidrive hybrid high-performance series. The machine is equipped with a special packaging unit, operating with a four-cavity mold from Glaroform and produces polystyrene cups in a cycle time of three seconds. The use of transparent PS and a film printed on both sides means that the cups have a decorative surface both inside and out.