Sol-gel coatings for high precision optical molds

The demand for high precision molds for the mass production of optical components is increasing. This paper describes a new approach for manufacturing precision optical molds. Firstly, thin ceramic sol-gel ZrO2-coatings were deposited onto pre-machined steel and nickel alloy molds. These coatings successfully solve the problem of sticking between the glass and the metal molds during high precision hot-pressing of glass lenses. Secondly, diamond machinable wear resistant sol-gel SiO2-xCy-coatings were deposited onto pre-machined steel molds for injection molding. Mechanical coating properties like hardness, elastic modulus and density were measured as a function of the sol-gel processing parameters.