Wednesday, July 23, 2008

Spin-cast Eyeglass Frames

Contributed by Irving J. Arons, Product Technology 1969-1994.

In the summer of 1976, Universal Optical, an eyeglass frame manufacturer called and asked ADL to see if it could develop a process for manufacturing an epoxy eyeglass frame, similar in properties to that of Optyl of Germany.

Optyl had developed and was marketing a high-style frame that could be shaped to fit the wearers face but that would hold that shape, unlike normal plastic frames that quickly loosened on the face. Plastic frames, until that time, were typically made of cellulose acetate and the “ears” required a metal insert to maintain their shapes over the ears.

I led the case for ADL’s Product Development Section, ably assisted by my boss Richard Merrill, Arthur Drennan, and Karen Lanzon (Evans). The first thing we did was to develop an epoxy-based material that had the right properties – low viscosity, quickly cured, and that had the proper hardened properties required for an eyeglass frame, i.e., rigid, strong, clear (so that it could be dyed to any color), and malleable when heated for adjustment. After producing and testing several formulations, we found the right formula and went on to the next problem.

Our biggest problem was developing a method for making finished frame parts. We settled upon a method used in the jewelry and small pewter figurine businesses, spin casting. After much trial and error, we were finally able to develop a process that produced both the ear pieces and frames – after overcoming a major problem of removing small air bubbles trapped in the parts that threatened to ruin our attempts. Arthur Drennan came up with a brilliant idea for venting our molds –using soda straws -- to overcome this problem.

Next we developed a dyeing process for coloring the frames according to the style of the day, gradient colors, and finally, found the right urethane coating to produce a lustrous finish.

After about three years of experimentation and development, the process was transferred to the client company’s plant in Providence, RI and a pilot program initiated. Unfortunately, Universal Optical was beset with other problems by this time, and the epoxy frame production was never commercialized. We were, however, able to obtain a patent (1) on the process that was assigned to the company.

1. U.S. Patent No. 4,294,792, Molded Plastic Parts, Particularly Spin-Cast Plastic Parts for Eyeglass Frames, Irving J. Arons, Richard E. Merrill, Arthur P. Drennan, October 13, 1981.

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