(FORTUNE Magazine) – Ever since modern manufacturing began in the 19th century, the biggest delaying factor in getting new products to market has been the industrial counterpart of astronomy's black hole--the so-called manufacturing middle, where unpredictable amounts of time and money can disappear. We live in a digital age, when durable products from cell phones to automobile-engine parts are created using CAD (computer-aided design). But except for a few simple metal items, hardly any of these designs can be turned instantly into three-dimensional objects by feeding them into, say, those other digital wonders, CNC (computer numerically controlled) machine tools.

Most metal and plastic products and parts aren't machined at all but are cast and stamped by the thousands. Before companies go to the great expense of tooling--making the necessary molds and dies--they handcraft prototypes of clay, wood, plastic, or other materials. These are passed around to design teams, marketing people, even consumer focus groups, to catch flaws and get comments. Some prototypes must be sturdy enough for testing as parts inside engines. Once the design is set, manufacturers resort to moldmaking processes as cumbersome as wax casting, which dates back to the ancient Egyptians and Chinese, who used it to make jewelry and weapons.

The middle phase can swallow up several years. But the manufacturing equivalent of Star Trek's warp drive, which would allow companies to bridge this black hole, is beginning to appear. Look at those convoluted pollution-control filters for industrial plants, displayed by the two young entrepreneurs in the photograph. The filters were made of ceramics directly from a CAD drawing by a machine that uses ink jets similar to those in a computer printer. Instead of ink, this machine can deposit a liquid binder on layers of powdered ceramics to create a variety of shapes. No handmade prototype or slow, expensive tooling here. Goodbye, ancient Egyptians and Chinese!

IMPOSSIBLE TO MAKE UNTIL NOW

The filters, by Specific Surface of Franklin, Mass., are remarkable in another way. Their complex interior structure, built up in layers, is impossible to make by traditional methods like molding or machining. The filters have eight times as much interior surface area as older types, and a version designed for electric utilities is ten times as efficient in removing particles from the stack gases of coal-burning power plants. The first filters will be installed soon at two Southern Co. plants near Birmingham, Ala.

Because the filters are made in a way that eliminates all steps between CAD drawing and production, they're the most dramatic example of a fast-growing new technology called rapid prototyping, or simply RP. Sales of RP machines and related services zoomed 43% in 1997, to $615 million, estimates Terry Wohlers, an RP guru and head of Wohlers Associates, a research firm in Fort Collins, Colo.

Like a kangaroo carrying a baby in its pouch, RP also encompasses a smaller but exciting new technology, called rapid manufacturing, that seems destined for big growth spurts. When the shapes made by RP machines are not mere models but salable end products, like those filters, the machines have taken on the added role of rapid manufacturing. In another version of rapid manufacturing that's springing up, RP machines quickly turn out molds that offer a shortcut to volume production.

RP is already saving companies millions in its main role: making models of proposed products and parts in a hurry. Companies large and small, from Detroit automakers to tiny design shops, are enthusiastic users of RP machines, which range in price from $50,000 to $500,000. One of fast prototyping's biggest fans is Thomas Sorovets, head of Chrysler's RP lab in Detroit. To shrink the design part of manufacturing's black hole, Sorovets' lab keeps ten RP machines running unattended around the clock. They turn out 3,000 objects a year of various types, ranging from dashboards to transmission gears to the intake manifolds that sit atop a car engine. An intake manifold, shaped like an octopus, can be made in transparent plastic in four to eight days. The old way of bending and welding steel tubes took as long as three months.

At 3M, RP is used to make both product prototypes and working parts for 3M's own production machines. Prototypes include myriad products from respirator masks to tape dispensers. Says Marge Hartfel, a senior engineer at 3M's rapid prototyping center in St. Paul: "Just about every program 3M has invested in has been touched by RP." Savings from RP, running into hundreds of thousands and even millions of dollars on a single project, are common at 3M and other companies.

Prototype machines use a variety of methods to transform CAD drawings into solid objects. All the techniques, though, have elements in common. A computer translates a CAD image into slices of a 3-D object that can be made from layers of plastic, starch, powdered ceramics or metal, or paper. In most RP machines, lasers shape the layers.

As usual with invention, one individual's impatience was the propellant for the rapid prototyping industry, now barely a decade old. Its father, Charles W. Hull, 58, still works as vice chairman and chief technology officer at the RP company he helped found in 1986, 3D Systems of Valencia, Calif. As an engineer, Hull had always been bothered by the long time it took to make prototype models of plastic. They had to be machined by hand, he recalls. If more than one was needed--generally the case in industry--molds for making plastic prototypes had to be individually machined.

The building blocks of a better system were lying around. Hull had been working for a small company that used ultraviolet lamps to harden photosensitive plastic coatings on glass and other objects. One of his insights was to substitute a laser for an ultraviolet lamp. "But taking that insight to a practical machine came slowly," Hull recalls, and required several years of Edison-style perspiration.

The result was the first prototyping machine, introduced by 3D Systems in 1987. It could fabricate small, transparent plastic parts from CAD drawings in hours or at most days. The machine builds the model in layers, from the bottom up. A laser, which causes molecules of a photosensitive liquid resin to fuse when it hits them, races above a vessel filled with the resin. The laser first traces the outline of a layer on the resin's surface. Next, like an artist shading a panel in a pencil drawing, the beam crisscrosses the whole outlined area to harden it. Then the platform holding the model sinks so the layer is barely awash in liquid resin, the laser goes to work solidifying another layer atop it, and so on. When the translucent object is done, it is raised from the vat, dripping like a mermaid just emerged from the sea.

Hull dubbed the process stereolithography, and it still dominates RP. The resins were--and still are--very expensive: A gallon of acrylic blends of photocurable liquids fetches about $750. But so great is industry's hunger for prototypes, in an era when the pool of high-paid artisans who can make them by hand is shrinking and time to market is king, that designers were glad to get the first RP machines at any price. 3D Systems has grown to an $80-million-a-year public company that's still No. 1 in the field by far.

LIKE A DEMENTED ICE DANCER

Before long other inventors jumped in. Michael Feygin, an immigrant Russian engineer, hit on the idea of building prototypes from inexpensive slices of paper. His company, Helisys of Torrance, Calif., makes remarkably sturdy objects by a process called laminated-object manufacturing. A blue CO2 laser traces each layer by burning, moving like a crazed ice dancer carving a turn here, a straight line there. Successive layers are bonded by adhesive. Helisys, whose machines have modeled auto steering wheels, bumpers, and other shapes that feel like wood to the touch, is a $12-million-a-year public company.

Meanwhile, a group of MIT inventors led by Emanuel Sachs, a slender, unassuming professor of mechanical engineering, chafed at the RP industry's inability to make prototypes, as well as molds and production parts, from ceramics and metal. The early RP machines could make a metal prototype only in a roundabout way. First a plastic model had to be "invested," or clad in a heat-resistant material such as a ceramic. Then the model was "sacrificed" by melting, just as the ancient Egyptians melted a wax model inside a mold to clear the way for a bronze casting. This leaves a mold suitable for making a metal or plastic prototype.

Why not skip that stage, Sachs asked, and make sturdy parts directly from CAD designs? He and his 30-person shop at MIT have become the leaders in a branch of RP based on the same technique that enables computer printers to produce documents by squirting ink through jets. Instead of ink, RP machines, licensed to use MIT's approach, squirt a binder on layers of powdered steel, ceramics, or even starch that are spread by rollers.

The machines to which Sachs' idea has given birth, called 3-D printers, are fairly inexpensive by RP standards, with low-end versions in the $50,000 range. The bigger 3-D printers are only now realizing Sachs' goal of making commercially usable metal objects and molds directly from CAD designs. Soligen, a Northridge, Calif., company founded in 1992 by expatriate Israeli engineer Yehoram Uziel, has developed, under license from MIT, the ink-jet machine Specific Surface employed to make those ceramic filters. On its machines, Soligen also makes ceramic molds, directly from CAD drawings, suitable for casting metal automotive parts that are as strong as those used in commercial products and suitable for testing and small production runs.

NEEDED: LONG-LIVED MOLDS

Soligen's process still has limitations. The ceramic molds are made in one piece and can only be used once, since they must be destroyed to get at the part. But Soligen can make lots of molds quickly as needed. Many RP users, eager to go further, want rapidly made molds that can be used over and over for mass production. That would shrink the manufacturing middle some more, bypassing a conventional process in which a long-lasting mold is carefully carved out of a block of high-grade steel with CNC and other machines, then painstakingly finished by hand, a process that can take months.

Quickly made reusable molds, which put RP squarely in rapid-manufacturing territory, have started to appear. When Rubbermaid Office Products of Maryville, Tenn., got an urgent order in 1996 from Staples, the office-products chain, for a small plastic stand that holds sheets of paper vertically, Rubbermaid went to an RP service bureau in Dallas that had a machine made by DTM of Austin, Texas. The ten-year-old company, whose initials stand for "desk top manufacturing," has developed a sintering process in which loosely compacted plastic particles are heated by a laser to combine with powdered steel, layer after layer, into a solid mass.

The DTM machine speedily produced a metal mold from which Rubbermaid was able to make more than 30,000 plastic stands for Staples, priced at $3. Says Geoff Smith-Moritz, editor of the newsletter Rapid Prototyping Report in San Diego: "Though not very impressive looking, this product is a harbinger. More and more molds are being made this way."

In its purest form, rapid manufacturing would junk molds: Machines would spit out products directly from CAD designs. Extrude Hone, a company in Irwin, Pa., is getting ready to market a machine, based on MIT's ink-jet technology, that will make not only metal molds but also salable metal parts. In Extrude Hone's machine, powdered steel is hardened with a binder and infiltrated with bronze powder to create a material that is 100% metal.

MAKING METAL THAT'S DENSE

Powerful new lasers may also open doors to direct manufacturing. Such laser systems are being explored at national laboratories such as Sandia and Los Alamos, as well as at the University of Michigan, Penn State, and elsewhere. They may soon be available commercially. In the Sandia system, a 1,000-watt neodymium YAG (yttrium-aluminum-gallium) laser melts powdered materials such as stainless and tool steels, magnetic alloys, nickel-based superalloys, titanium, and tungsten in layers to produce the final part. The process is slow: three hours to make a one-cubic-inch object. But the part is just as metallically dense as one made by conventional means.

Sandia vice president Robert J. Eagan says the lab's researchers hope to see the process used to make replacement parts for the military's stored nuclear weapons. Commercial interest is high too. Ten companies, including AlliedSignal and Lockheed Martin, are participating in the program. Another 20 companies support research at Penn State, where the goal is to make big objects, such as tank turrets and portions of airplanes, as a single part.

Some experts look to a manufacturing future extensively liberated from today's noisy, hot routines. Instead of molds and machine tools, these visionaries foresee rows of lasers building parts, 3-D printers fashioning convoluted shapes no CNC machine can carve, and silent ceramic partsmakers replacing the traditional factory din. Many products turned out in future factories could be designed to take advantage of rapid-manufacturing techniques. Implantable drug-release devices, with medicine sealed in, could be made in a single operation, since 3-D printers can make a sandwich-like product.

Manufacturing pioneers find such possibilities intoxicating. "We could have naval ships carry not an inventory of parts but their images digitized on a 3.5-inch diskette, plus a bag of powdered metal and a rapid manufacturing machine," says 3-M's Marge Hartfel. Adds Brock Hinzmann, director of technology assessment at SRI International: "In two or three years rapid manufacturing will be on everybody's lips." In the meantime, the feats of fast prototyping are giving the factory folks plenty to talk about.

REPORTER ASSOCIATE Alicia Hills Moore