The Glass Ribbon Machine

In 1879, Thomas Edison and his research team developed a durable carbon-filament light bulb. In the 1880s and 90s, when glass had to be blown by hand, the skilled Corning glassblowers that Edison hired could produce two light bulb glass shells per minute, a pace that couldn’t meet the public’s demand for easy and inexpensive electricity.

Enter Corning master glassblower William J. Woods, who, in 1921, thought of forming the glass shells through holes in a metal plate. Collaborating with mechanical engineer and colleague David E. Gray, his idea developed into The Glass Ribbon Machine, which could produce up to 300 light bulbs per minute by 1926. Before the end of the century, newer versions of the machine could produce 1,600 bulbs per minute. From ASME.org:

A glass melting tank sat above one end of the machine, feeding a stream of molten glass from its forehearth down between two metal drums, which flattened the glass into a thick, glowing ribbon. This yellow-orange ribbon was laid onto a series of square plates, each with a small hole in its center, which were linked together in the manner of a bicycle chain and driven by sprockets at either end of the oval.

As soon as the glass ribbon was laid on the chain, the glass began to sink through the holes, giving nascent form to the future bulb blanks. A chained series of moving plungers above the chain descended on the hot ribbon, pushing compressed air into the sagging glass. And a third chain, below and inside the first, thrust up a series of split molds which snapped together around the forming glass to give final shape to the bulb blanks before unsnapping just as quickly to reveal the familiar light bulb configuration.

From the Corning Museum of Glass, this is high speed footage of “the machine that lit up the world,” now a relic from a pre-LED bulb era. It was preserved by the museum in 2016 after Osram Sylvania closed their Wellsboro, Pennsylvania plant, one of the last U.S. factories where ribbon machines were used.