The installation of two new lehrs is part of a major capital improvement program that began over a year ago. The lehrs will enable us to provide more consistent annealing thus enabling better lens performance in their intended applications. By using state-of-the-art lehrs, we have the added flexibility of annealing intricate and difficult shapes that previously would not have been possible.
In addition to providing a better environment for annealing, the lehrs will also be used for coloring and decorating processes. They will provide better color consistency with red and yellow colored lenses. This will give us the ability to achieve tighter transmission and chromaticity requirements. The lehrs will also be used to bake "cure" decorating enamel used to opaque certain portions of the lens surfaces.
"The convective heating methodology utilized by the new lehr equipment provides improved temperature uniformity over an increased furnace volume, thus producing more consistent colors and an improved anneal on our thick, intricate glass designs." - William Chen, Director of Research and Engineering
We decided to purchase lehrs from E.W. Bowman because they are the industry leaders. Since 1959, Bowman has been designing and manufacturing annealing lehrs for the glass industry. Their custom designed and manufactured lehrs are used all over the world. Each lehr was manufactured in the U.S. and was designed to be as energy efficient as possible. Natural gas is used to fire the lehrs and electric is used to power the eight circulating fans installed within each lehr. A convection approach is taken in order to take advantage of the air that is already heated. The design of the lehr allows for temperature control within a 10 degree F range (previously 100°F). This allows for better control of gas usage and flow during the lehr operation.