Technical Molding: Sophisticated LED lenses of liquid siliconeIn the technical molding exhibition area of ENGEL at the NPE2018, the focus is on the advanced processing of liquid silicone (LSR). Lenses for LED headlights will be produced on an e-victory 310/120 US injection molding machine equipped with a two-cavity mold by ACH solution (Austria). These technical parts represent a wide range of applications. From automotive to construction to street lighting, LSR is rapidly gaining in importance. This is due to its special characteristics. Highly transparent LSR has a lower yellowing index than standard lens materials, is UV-resistant, and stable across a very broad temperature range of -20 to +150 °C. In addition, even complex lens geometries can be efficiently and consistently produced with injection molding.
ENGEL has a great deal of worldwide LSR project experience in various industries, and is therefore considered a preferred partner of the lighting industry in the market introduction of the new lens material. This is the first time that ENGEL is presenting the production of LSR lenses at a trade show.
"Prerequisite for the economic production of advanced products with liquid silicone are automated processes and a high degree of precision and stability in the injection molding process", states Steve Broadbent, responsible for elastomer projects in the application technology of ENGEL in North America. "Thanks to its tie-bar-less clamping unit, the e-victory machine with its electric injection unit has shown itself to be predestined for this purpose." Free access to the mold interior simplifies setup and keeps the production cell compact. Since the mold mounting platens can be used all the way to the edge, the lens mold, which is larger in size due to the complex component structure, fits into a comparatively small 120-ton injection molding machine. In addition, the robot can access the cavity directly from the side and requires less vertical space.
The tie-bar-less injection molding machines by ENGEL impress with an outstanding parallelism of mold mounting platens. The patented force divider enables the moving mold mounting platen to follow the mold exactly while clamping force is building up and ensures that the initiated clamping force is distributed evenly across the surface. This prevents burr formation even when processing low-viscosity materials such as LSR. The components require no rework and can be used immediately after the injection molding process.
ENGEL is implementing the high-tech solution in cooperation with its partner. The mold as well as the dosage system were developed and constructed by ACH solution, and the mold is using the new electric nozzle control ServoShot.
As systems provider, when processing LSR ENGEL also integrates all components of the production cell into a common control so that the entire process, including LSR dosage and handling, can be adjusted and controlled via the CC300 operator panel of the injection molding machine.
Confidently control LSR processes with ENGEL tie-bar-less technologyThe NPE2018 once again confirms the leading position of ENGEL and tie-bar-less injection molding machines in LSR processing. Altogether, four LSR applications with ENGEL injection molding machines – three of which with tie-bar-less machines – will be presented at the trade show. At Wacker Silicones (headquartered in Germany) in the South Hall, Booth S24179, coasters will be produced on a hydraulic victory 200/120 with a 4-cavity mold. An additional tie-bar-less application is being run on a victory 200/55 at the booth of the tool builder Burteck from Windsor, CT (US) in the South Hall, Booth S30045. And Shin-Etsu Silicones from Akron, Ohio, will produce eyeglass lenses on an all-electric e-mac 170/55 machine using an optical grade LSR with the mold coming from Roembke (Ossian, Indiana). The Shin-Etsu booth is in the South Hall, Booth S20125.