Remanufacturing, although an oftignored production strategy, has made some headway in a number of manufacturing arenas. A survey by Robert T. Lund, a research professor at Boston University's Center for Technology and Policy (see text), identified 450 major remanufacturers. Among the companies, both large and small, that are already making productive and profitable use of the process are:

* AT&T Technologies Inc. The relephone company has been remanufacturing phones and other telecommunications equipment since Alexander Graham Bell scrounged parts from No. 1 to make No. 2. In recent years, its activity has grown in size and sophistication. Now some 70% of all handsets provided by AT&T are remanufactured. Divestiture -- with all the competitive options it opened -- is likely to change the marketplace somewhat. But remanufactured equipment, produced at 25% the cost of new, is still the cheapest route to go.

* Detroit Diesel Allison, a division of General Motors Corp. Since January, DDA has been remanufacturing 8.2-liter diesel engines, and GM made quite a to-do about its new product at the recent Indianapolis 500. Its "Fuel Pincher," the company claimed, costs less than an original-equipment manufacturer's engine, takes less time to install, is built to new specifications, and is covered by a nationwide warranty. Buyers get a credit for their old engine core, and if that isn't enough, DDA estimates that a Pincher-powered truck will save $34,538 in fuel over an eight-year period.

* Dickenson Lines Inc. of Princeton, Minn, (recently purchased by No-Ko-Ne Corp.). If bus fares haven't gone up recently in San Francisco, Dayton, or Madison, Wis., it may be to the credit of DLI, which, since 1979, has been providing an assortment of used vehicles -- refurbished, rebuilt, and remanufactured -- to various municipalities. The remanufactured item, an old bus upgraded to current standards, costs from $50,000 to $80,000, about half the cost of new. It will last an additional 8 to 12 years.

* Unimation Inc., of Danbury, Conn., a subsidiary of Westinghouse Electric Corp. A premiere robot manufacturer, Unimation has been remanufacturing its one-armed wonders since 1978, primarily to bring older units up to date technologically. The activity has proven so sucessful (buyers save an average of 35% on the cost of a remanufactured robot) that Unimation now devotes an entire plant to busting up the old, upgrading the equipment, and transforming it into like-new.

* United States Machine Tools Inc., of Hartford, a wholly-owned subsidiary of Numex Corp. This company used to produce new machine tools, but it found the market too competitive. Remanufacturing, however, has given it a new lease on life: In the past six years, sales have climbed by 50%. USMTI concentrates on tools 15 to 30 years old and worth $70,000 or more -- Pratt & Whitney Tape-O-Matics, Burgmaster turret drills, Cincinnati Milacron vertical and horizontal milling machines, to name a few. Buyers enjoy savings of from 30% to 60%.