ELMET and DOW partner on turnkey system for LSR optics of LED headlights

Partnered with DOW, ELMET has further improved the manufacturing technology for the main optics of LED headlights with Adaptive Driving Beam (ADB) functionality to suit it for use with a grade of LSR specifically developed for optical applications.

Consistently high part quality is ensured by a combination of ELMET’s high-precision SMARTmix TOP 7000P dosing system with the mold’s SMARTshot E cold runner system, in which the needle is positioned servo-electrically when the nozzles open and close.

ELMET’s turnkey systems

ELMET developed turnkey systems which are mold-making facilities using proprietary dosing systems and cold runner.

SMARTmix TOP 7000P dosing system is the first commercially available dosing pump designed to be FDA-compliant, which ideally suits it to high-purity optical LSR grades. The volumetric meter’s high measuring accuracy of 0.0156ml per count pulse ensures high mixing quality and process consistency.

Virtually abrasion-free delivery also opts out any contamination of LSR by abraded metal from the pump which would impair functionality.

Developing turnkey systems for manufacturing LSR optics for adaptive LED headlights requires a combination of expertise in materials, mold-making, dosing and injection molding.

SMARTshot E valve gate cold runner system has a compact servomotor for moving and positioning the nozzle needle for precise control of sprueless cavity filling. Needle opening can be set in the µm range, making injection process more balanced than with stepper motor drives.

Besides that, mold gaps of less than 10 µm ensure no flash is formed on the optical components despite the material’s very low viscosity.

Turnkey system for DOW’s optical LSR

DOW and ELMET are currently working together for a turnkey system for manufacturing ADB multiple light guide lenses from the optical LSR grade SILASTIC MS-5002.

ELMET is responsible for designing the sophisticated mold for injection molding the geometrically highly complex parts.

The part’s volume is about 35cm³, corresponding to a weight of around 37.5g, based on the LSR’s specific density of 1.07g/cm³. With the widely varying cross-sections, this results in challenging cycle times for LSR mass production.

ELMET has tailored the mold’s cold runner to the selected LSR grade’s viscosity and flow behavior, so to ensure maximum process stability and provide uniform cooling.

The mold inserts, made from a special steel alloy, are heat-treated and polished – mold surface is perfectly transferred onto the surface of LSR part, making it possible to meet stringent optical industry requirements for light guides and outcoupling sections of the lens.

“We are convinced that our combined technical expertise in silicone chemistry, LSR processing and optics will, into the medium term, remain key to unlocking high added value along the automotive LED headlight value chain with silicone light guide lenses,” explained Thorsten Häuser, Development Manager of ELMET.