Heavy metal

THE biggest engineering companies nowadays prefer to talk about “additive manufacturing” rather than “3D printing”. One reason is that printing is not quite the right word for some of the technologies given this label. Whereas hobbyist-scale 3D printers typically build a product by squirting out blobs of plastic, a technique called selective laser melting zaps successive layers of powder with a laser or ion beam, hardening only certain bits.

Another reason for being picky about terminology is that big companies want to stress the “manufacturing” aspect: the technology has moved beyond the development labs and is now being used on the factory floor to make complex metal parts. A pioneer in making the selective-laser melting equipment used in factories, SLM Solutions of Germany, will float on the Frankfurt stock exchange on May 9th.

In gas turbines, the blades move at the speed of sound and heat up to 1,400°C. The elaborately shaped components are hard to design and costly to make. But Siemens, a big industrial group, is using SLM Solutions’ machines to cut the cost and the time needed to replace the blades on customers’ turbines when they break. It hopes eventually to cut the time from order to delivery from 44 weeks to perhaps four.

For simpler mechanical parts, additive manufacturing is a long way from replacing traditional mass-production techniques such as casting and welding. But 3D printing allows designers to imagine shapes that would be impossible to create through older techniques, besides greatly speeding up prototyping—for turbine blades and similar parts, from 16-20 weeks to just 48 hours, Siemens says.

Additive manufacturing cuts the cost of tooling and materials: a piece can have all of its holes incorporated into it, with great precision, as it is built up from powder, instead of needing to have them expensively drilled afterwards. Siemens hopes to cut the cost of some parts by perhaps 30%.

Last but not least, says Andreas Fischer-Ludwig, an executive at the company, is the power it gives Siemens with its suppliers. As it gets easier to make low-volume, specialised parts in-house, Siemens gains bargaining-power when it comes to outsourcing such parts to other firms.

The technology is still being perfected. For example, some pieces need further finishing to make their surfaces less prone to corrosion. And the lasers used in the process do not come cheap. Such obstacles to the wider adoption of 3D printing are sometimes underestimated by its boosters, says Terry Wohlers, an industry analyst. That said, the market is growing rapidly. The revenues of makers of 3D-printing equipment and supplies worldwide grew by almost 40% last year, Mr Wohlers reckons, far faster than he had expected.

If patience and deep pockets are what are needed, this again will give the biggest firms an advantage—another reason why relatively small turbine-makers like Alstom are vulnerable to being swallowed up by bigger rivals like GE and Siemens (see article).

Aircraft engines, subject to even higher standards of reliability than turbines, are another area in which the engineering giants have implemented additive manufacturing. GE is using it to make fuel nozzles for its next-generation Leap engines (made in collaboration with Safran of France), which will power the new versions of the Boeing 737 and Airbus A320 jets. GE says the nozzles will be 25% lighter and five times more durable than their predecessors—and since there are 20 or so in each engine, the weight savings are significant.

Airbus is already making bits of its planes, such as mounting brackets, by additive techniques; and it dreams of one day “printing” entire fuselages. There is still space in the market for smaller firms like SLM Solutions that make the 3D printers themselves, and for innovative startups. But many may end up in the arms of the giants, just as in 2012 GE bought Morris Technologies, a 3D-printing specialist, thereby denying its rivals Morris’s technologies. So far 3D printing has conjured up images of hobbyists turning out novelty items in their kitchens; increasingly it is about giant engineering firms turning out sophisticated parts in factories.