“The high cost of tooling up a factory has long been a barri...

Read the text to answer 33, 34 and 35.

As epoch-making as Gutenberg’s printing press, 3-D printing is changing the future.

By Roff Smith

Rocket engine parts, chocolate figurines, functional replica pistols, a Dutch canal house, designer sunglasses, a zippy two-seater car, a rowboat, a prototype bionic ear, pizzas — hardly a week goes by without a startling tour de force in the rapidly evolving technology of three-dimensional printing. What sounds like something out of Star Trek — the starship’s replicator could synthesize anything — is increasingly becoming a reality. Indeed, NASA is testing a 3-D printer on the International Space Station to see if it might provide a way to fabricate meals, tools, and replacement parts on long missions. Back on Earth, long-term business plans are being reimagined. Airbus envisions that by 2050 entire planes could be built of 3-D printed parts. GE is already using printers to make fuel-nozzle tips for jet engines. And interest isn’t limited just to corporate giants.

The high cost of tooling up a factory has long been a barrier to developing niche products. But now anyone with an idea and money could go into small-scale manufacturing, using computer-aided design software to create a threedimensional drawing of an object and letting a commercial 3-D printing firm do the rest. Since a product’s specifications can be “retooled” at a keyboard, the technology is perfect for limited production runs, prototypes, or one-time creations — like the one-third-scale model of a 1964 Aston Martin DB5 that producers of the James Bond film Skyfall had printed, then blew up in a climactic scene. And because a 3-D printer builds an object a bit at a time, placing material only where it needs to be, it can make geometrically complex objects that can’t be made by injecting material into molds — often at a considerable savings in weight with no loss in strength. It can also produce intricately shaped objects in a single piece, such as GE’s titanium fuel-nozzle tips, which otherwise would be made of at least 20 pieces. “People read about the fabulous things that are being made with 3-D printing technology, and they are led to believe that they will be able to make these things themselves at home and that what they turn out will be of a really high standard of workmanship, it won’t be.” Dr. Rowly, a tech expert says. While consumer printers may one day allow us to make whatever we like, Rowley envisions a different grassroots revolution, one where people can test ideas that once would never have made it off the back of an envelope.

(Available: http://ngm.nationalgeographic.com/2014/12/3d-printer.)