The factories in Charleston, S.C., and North Brookfield, Mass., which make glass for the precision lenses used by computer-chip makers, employ about 135 people. Two dozen employees will be reassigned to other locations, the company said Thursday.
The plant in North Brookfield will close by the end of the year and the Charleston operation will be shut down early next year.
The materials company, which specializes in fiber-optic and glass products, is consolidating manufacturing of ultra-clear glass and fluoride crystal materials at its factory in Canton in northern New York.
It also is concentrating production of fluoride crystal components at its Corning Tropel subsidiary in Fairport, a suburb of Rochester.
Corning said it will take a pretax charge of $70 million to $80 million. The changes will save the company an estimated $12 million a year.
"The dramatic cyclicality of the semiconductor equipment market requires greater flexibility and lower costs than we currently have in our structure," said James Steiner, general manager of Corning's specialty materials unit.
"Although we believe the market is currently improving, we are taking this action to attain the flexibility and cost structure required to succeed through the entire up and down cycle."
Corning was badly shaken by the telecommunications industry's rapid slowdown in 2001. In October, helped by robust sales of flat-screen glass used in computer monitors and television, it announced a profit for the first time in more than two years.
The company gets less than half its sales from optical networking products, notably optical fiber. Those products accounted for almost three-quarters of its sales in 2001.
Under James Houghton, who returned as chief executive in April 2002, Corning has shut 13 plants and nearly halved its work force to 22,500.
The company anticipates sales could dip as low as $3.2 billion this year from $7.1 billion in 2000. With one-time costs included, Corning doesn't expect to return to profitability until next year.
Corning shares fell 19 cents to close at $10.85 on the New York Stock Exchange.