Engis Unveils New Polishing Process
HENLEY-ON-THAMES, England, June 19, 2014 — Engis has developed a new process for polishing a variety of laser-grade optical surfaces.
The process uses diamond slurry and composite polishing plates to polish surfaces made of zinc selenide, zinc sulfide, germanium, silicon, calcium fluoride or magnesium fluoride.
The company said this enables manufacturers to rapidly change between different materials, reducing setup times and costs, and eliminates edge rounding normally associated with pad polishing. The system causes fewer visual sleeks, according to Engis, while achieving surface flatness to λ/8 and a scratch-dig rating of 20-10.
For more information, visit www.engis.uk.com.
- calcium fluoride
- An optical material used in place of crown glass to produce lenses with extraordinary correction of chromatic aberrations. Its high coefficient of thermal expansion and its tendency to absorb moisture limit its range of application.
- A crystalline semiconductor material that transmits in the infrared.
- magnesium fluoride
- A colorless, crystalline compound whose low refractive index (n = 1.38) makes it effective as a lens antireflection coating when deposited by thermal evaporation in a near vacuum. This process develops a coating that is robust and stable, though only a few molecules thick.
- zinc sulfide
- A polycrystalline material that transmits in the infrared; it is used as a phosphor in x-ray and television screens.
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