DESIGNERS are lofty idealists who know how the world ought to behave. Unfortunately, those who have to turn their fine ideas into real things soon find out that “ought to” is not the same as “does”. Here, a hole cannot be drilled because something sticking out next to it will get in the way of the drilling machine. There, attaching the widget-wheel to the thingummy-tube will take too long and hold up the entire production line. One part has ended up the wrong shape, and another's place in the assembly schedule means that to fit it a technician has to crawl into a space only a child could enter.
In an ideal world, therefore, the design and manufacturing process would be perfected before anything had to be made flesh. These days, however, such a fantasy world exists: it resides in the vast virtual spaces inside computers. In the past few years certain industries—car and aircraft makers, most of all—have been simulating ever more aspects of production in these pleasure palaces of the imagination before carrying them out for real, and—so they say—saving a great deal of time and money in the process.
The roots of “virtual manufacturing” are in computer-aided design (CAD). This gave to designers what word-processors bestowed on writers: the freedom to make changes without having to redo the whole thing. But there is more to CAD than simply being a whizzy drawing-board. Its true potential lies in the form in which a drawing is stored: digital data.
Such data can be copied and shared, allowing designers in different continents to collaborate on the same project. More importantly, the data can be given to other kinds of computer programs to crunch. This was what Boeing's engineers did when they designed the 777 jetliner. Using a system called CATIA, developed by Dassault Systèmes, a French software company, they assembled an entire virtual 777 to make sure the hundreds of thousands of parts fitted—redesigning any that did not do so before letting them be manufactured. Consequently, when the first real 777 was constructed, it fitted together almost perfectly—with little of the coaxing and machining that assembly normally requires.
Of course, replacing expensive prototypes with computer models is not a new idea. Virtual reality, usually involving the donning of a headset for the three-dimensional effect, has been much touted as a tool for designers. It lets them see, for instance, a cockpit from the pilot's viewpoint and thus make sure all the instruments are within reach. In practice, though, they usually find that these details can be worked out less tediously and more accurately on a normal computer screen.
Exotic headgear and other such diversions do, however, appeal to customers, since they allow them to join the engineers in electronic fairyland. General Motors' portal to this realm is their version of a device called “the Cave”. This is a small room with stark white walls and a couple of video projectors mounted on the ceiling. These beam a stereoscopic pair of images on to the floor. Someone wearing a special pair of glasses can see these as a three-dimensional model. The company uses the Cave not just as a design tool, but also to see how potential customers like the inside of its new vehicles. Some are so taken in by the effect that they try to put (real) cups of coffee they are holding down on (virtual) surfaces inside it.
The Cave, however, is still just a fancy display unit. Other systems do not merely show things off, but allow them to be messed around with. Ten years ago, car makers would expend dozens of prototypes, at up to $1m apiece, on crash testing during the design. These days they destroy virtual vehicles; real ones are used only in the final safety tests demanded by law. And now even crash-test dummies, those hapless plastic stand-ins for human beings, have electronic stand-ins of their own. In March, First Technology Safety Systems in Michigan—which has 80% of the world's real dummy market—released its first virtual ones. According to the company, not only does this reduce the need for new dummies, but a computer can run as many gory scenarios in a week as real testers can engineer in a year.
But if computers can depict something that has not yet been built, they can show it in the process of construction too. This, perhaps, is virtual manufacturing in its purest form. Systems such as DMAPS, made by Dassault, and a suite of programs from Tecnomatix Technologies, a company based in Herzlia, Israel, simulate entire factories. Engineers can calculate the most efficient route for a spray-painting robot to take around a car body, work out how quickly parts must be supplied, look for bottlenecks or even tell if a human worker's task is likely to give him backache.
These simulations catch many problems before a factory has been built. More importantly, because they get their data straight from a CAD system, production engineers can bounce problems back to the designers, instead of just cursing them for their ignorance. The car industry makes impressive (though probably exaggerated) claims about the benefits. Chrysler, which has used both Tecnomatix's and Dassault's tools, says that a decade ago it took five years to get from the concept to the production of a new car. The company's latest model, which rolls out this autumn, completed the course in half that time.
The ultimate aim is to “virtualise” the entire production process. British Aerospace is one company making some headway towards this with the method it uses to design fighter aircraft. A client's wishes are investigated first by running computer models of the sorts of battles a plane might be used in. This gives the designers performance criteria to aim at. Once a design is set, different bits of the manufacturing process are tried out on computer: a virtual pipe-bending machine, for instance, makes sure that the fuel lines which snake their way through the airframe can be created without wrapping themselves around the machine and bringing it to a halt. After various tests on the virtual prototype (such as making sure vital systems are insulated from lightning strikes), its ceiling, rate of climb and other handling characteristics are fed into a flight simulator. This lets would-be pilots test its performance.
It is not, however, a seamless process. The flight simulator, for instance, cannot simply download the virtual aircraft from the design computers. This is symptomatic of the problem with virtual manufacturing: it is still, despite its promise, a sporadic and haphazard phenomenon. There are many systems, and few standard formats. Manufacturers have highly specialised needs, so they have tended to develop their tricks in-house—which is expensive.
But CAD, too, was first created by manufacturers for their own purposes (the pioneers were car makers, which may be why they are now so advanced in virtual manufacturing). Only later did companies that specialised in it spring up. And some effort is being made to develop standards for the data that virtual manufacturing systems will swap. The Manufacturing Systems Engineering Group at America's National Institute for Standards and Technology, which is led by Charles McLean, is working on things such as the best way to represent a human being. Currently, depending on what they were designed for, some packages can take account of finger movements, while others treat a hand as a single lump.
Dr McLean envisages that one day, before buying robots for its factory, a company may buy virtual ones from the suppliers' catalogue for a nominal fee. These, thanks to a standard language, will be able to plug straight into its virtual shop floor. There could be a virtual library of parts—perhaps on the Internet, which already has a standard code, VRML, for describing solid objects. Eventually, engineers will work entirely in the abstract world of forms— emerging only for the unpleasant, if necessary, duty of turning them into things tangible enough for people to buy.