Making A Pair of AO Glasses - PART 1

 Taken from The American Optical News, Volume 5,

Dated Feb. 11, 1944 - Jan. 26, 1945

 

If one wishes to follow the steps which ultimately lead to a completed pair of AO glasses, he must go first to the stockroom which is in the long building situated behind the Power House and along the bank of the Quinebaug River below the falls. Here the pair of glasses starts its growth into the finished product.

A Picturesque Scene

The Molding Department, D1R, where the glass goes from the stockroom, is a fascinating place - and a warm place on a cold winter’s day. There are two long rows of rotary furnaces, and the room resounds to the rhythmical clamor of the tongs and presses. Everyone seems to be in constant motion; there is no waiting between various steps in an operation.

Glass In Form of Squares

The glass comes from the Pittsburgh Plate Glass Co., Pittsburgh, Pa., by the carload in boxes of one gram variation per box. Boxes have an average weight of about 300 pounds of glass. It arrives in the form of little squares, each of which has been weighed according to the specifications of the job. For the glass is made up according to our formula, and it is checked by preshipment and shipment samples. The Plate Glass Co. submits a preshipment sample for approval here and takes an AO sample to test and be sure it is all right before using.

The Rotary Furnaces

There are 22 rotary furnaces and two hand furnaces in the Molding Room. The glass is placed in hoppers by girls known as “helpers.” And they live up to their name. Each girl feeds five of the furnaces. The glass is fed on a slowly revolving hearth inside the furnace whose temperature is from 1200 to 2400 degrees F. By the time the little squares of glass have reached the door of the furnace, they have become soft and pliable from the heat and a rosy pink in color.

The Operation

Fine sand has been spread on the revolving hearth of the furnace so that the glass won’t stick when the operator pulls out the little squares deftly, one by one, with a hook poker. He pulls them with a flick of his wrist into the mold, puts each one into the molding press and steps on a pedal which molds by air pressure. There are half a dozen or so molds, and after filling them all, the operator starts again after he has dropped each lens into the molding basket which rests in front of him.

The Final Process

When the basket is full, it is taken to the lehr, or annealing oven, where, in going through, the lenses are annealed to relive the strain. By the time the glass has made its slow way through the lehr, it has gradually cooled off and is ready to go through the Inspection Department where the rejects are taken out and the rest edged. Then the lenses go to the Grinding and Polishing Department, D3R, for the next step toward the finished product. Here the lenses are ground and polished.

The Molding Room is an interesting place. It is the beginning of the long process which finally results in a pair of American Optical glasses. The men in the Molding Room must be quick, adept and well-coordinated, for they use both their hands and their feet in operating. A good molders does very many pairs of lenses a day, and the men in D1R are good molders.

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