3D printing technology

Totally individual layer by layer

The more difficult the better. With 3D printing technology, designs can be realised at the press of a button that were previously impossible. At the same time, they lift individualisation to a new level. And the costs? They become a side issue, as the example of GE Inspection Robotics shows.

Daniel Meierhans,

The pipes are closely packed together in the steam boiler of a power plant. The scanner that inspects the freshly welded seams has to make do with a mere 12 millimetres. “That is typical for our requirements,” explains Viktor Klein, head of sales at GE Inspection Robotics. “Every inspection task is unique. Whether it’s between the blades of a gas turbine, in the narrow space between the immobile stator and the rotating components of an electricity generator or on the external walls of a large tank.”

Since 2006, the joint venture between GE and ETH Zurich has been developing and producing highly specialised robots and devices that reliably and, above all, efficiently inspect pipes, tanks, turbines and generators in power plants or in oil and gas production for damage. With their high degree of specialisation and small quantities, the rapidly growing company is typical of many Swiss industrial companies. For them, technologies that they can use to produce solutions that are as customised as possible are crucial.

The inconspicuous difference

The key component, thanks to which the sensors of the circular palm scanner fit precisely between the tightly lined-up tubes, is a steel clip that, at first glance, looks inconspicuous. With this, the measuring unit and the position sensors are attached to the tube in such a way that the seam can be scanned in a reproducible manner. The only distinctive feature of the clip is the slightly rough-looking surface.

GE Inspection Robotics is thus among the first Swiss companies to not only produce plastic components using additive procedures, but also print crucial metal parts. In this process, a laser or electron beam melts the design from a fine metallic powder, layer by layer. This layered construction is visible in the surface structure.

Every geometry will be possible

The three greatest benefits of printing: firstly, the individual parts and small series can be produced at an unrivalled speed as no tools need to be manufactured. Secondly, all the limitations of traditional casting and milling techniques when it comes to the geometry of the components are eliminated. Even structures with extremely thin walls, undercuts and hollow spaces can be produced in one piece. And thirdly, the design can be continually adapted to new requirements without any increase in production costs. The individualisation is therefore no longer restricted to certain parameters.

1/7 3D printing allows production directly from the construction data. This saves a great deal of time and – in the case of individual parts and small series – also a lot of money. The laborious manufacturing of moulds that is necessary for casting is no longer required.

2/7 With the printed frame, the sensors of the Palm scanner can be attached extremely flush to the pipes of a steam boiler. For different pipe diameters, a new clip can also simply be designed and printed. Because of this, the production costs increase only slightly.

3/7 The inspection robots and scanners from Alstom Inspection Robotics are individually assembled in the Zurich Technopark and revised after use. “If it weren’t complicated, we would hardly be producing our robots in Switzerland,” explains production manager Stanko Bajunovic.

4/7 The development and production of the inspection robots requires maximum expertise in both engineering and production. The smallest details make the crucial difference and individual adjustments have to be implemented precisely.

5/7 Before deployment, the systems are tested thoroughly. Here, a camera sensor is being calibrated. It belongs to an ultra-flat robot that uses a tapping technique to detect material damage in the narrow gap between the stator and the rotating components of a generator.

6/7 The engineers test new functions and designs in their own laboratory. Mobility and the measurement performance are optimised on and in the replica boilers, pipe systems or turbine and generator components – some of which are also printed.

7/7 For the systems to work robustly and reliably in the field, the utmost precision is required. Here, the self-developed electronic boards are undergoing a quality inspection before being installed in a robot.

1/7 3D printing allows production directly from the construction data. This saves a great deal of time and – in the case of individual parts and small series – also a lot of money. The laborious manufacturing of moulds that is necessary for casting is no longer required.

Because tailored products can be produced directly from design data at the press of a button using additive procedures, these – along with the Internet of Things – are among the key technologies for end-to-end digitalisation of the industry. At the end of the development towards Industry 4.0 – as the climax, so to speak – is mass production in a lot size of one: every customer receives an individual product version that is printed for him or her on demand. Admittedly, this is still a vision of the future. But for individual components, printing already pays off.

Live within a few days

“In our case, casting or milling would be much more expensive,” Bajunovic concludes. The clip has a wall thickness of just one millimetre and consists of several components. Milling such thin parts is hardly likely to work the first time. In addition, with the additive procedure, the designers have far fewer constraints to pay attention to and can therefore concentrate fully on the optimum design. However, for Bajunovic, it is the speed that is decisive: “We are constantly continuing to develop our products together with our customers. Thanks to printing, we can use adapted and new components live within just a few days.”

The result is robots and scanners that are perfectly tailored to every single inspection task. And, at the end of the day, that saves a lot of money. “Every day that a power plant is at a standstill results in production downtime amounting to around one million dollars,” Klein calculates. “Our devices reduce the inspection times by 50 per cent or more.” For example, previously to inspect the welding work on the boiler tubes, every seam had to be x-rayed. Due to the radiation, the entire area had to be evacuated for this and the result was only available once the films had been developed the following day. “Thanks to its high level of reproducibility, the circular palm scanner achieves the same accuracy with ultrasound measurements that we can perform directly behind the welder,” Klein reports. 

From apertures to pasta

For Matthias Baldinger, co-founder of Additively.com, GE Inspection Robotics is a perfect example of how Swiss manufacturers can set themselves apart better with additive procedures. With his Internet-based platform, Baldinger builds a bridge between industrial companies and the growing number of 3D printing service providers: “Every plastic and every metal requires a specialist machine. A purchase makes sense for only very few. We help companies find the right supplier for every task.” More than 300 providers are already registered with Additively.com, and new ones are joining up on a weekly basis.

And demand is growing just as rapidly, as Baldinger stresses: “Three years ago, we had to explain to managers precisely what additive procedures actually are. Today, we usually quickly come to discussing concrete projects.” In the process, the activities are increasingly moving towards individual customer products: the high-end camera manufacturer Alpa, for example, already prints apertures that fit precisely to the lens geometry of the individual camera, the laboratory equipment manufacturer Tecan prints wash stations for a pipetting system, adapted for individual analysis tasks, and medical technology companies print patient-specific implants.

However, even traditional industrial Groups like Bühler are taking a close look at the new possibilities. And the manufacturer of production technologies for food and beverages does not just have components for its own systems in mind. The group is also evaluating what possibilities it can open up for its customers so that, for example, pasta manufacturers are able to print individual pasta shapes.

On the threshold of mass production

Baldinger is also convinced that, in the future, the range of applications will increase considerably: “The technologies are quickly developing further, and this is causing the prices to drop.” The consulting company Roland Berger Strategy Consultants expects the unit costs to be reduced to one third within the next few years. Among other things, the entry onto the market of the major German machine-tool manufacturers Trumpf, Aarburg and DMG Mori will ensure this. And the printer and PC specialist HP has also announced a new technology for 2016 that is said to be significantly faster and better.

“3D printing is not just changing the products, but also the supply chain.”

The aeroplane engine manufacturer GE Aviation will undoubtedly also make a significant contribution to the rapid development of the technology. The American company is preparing metal 3D printing for mass production with a factory for engine injection nozzles. This year alone, 4,000 nozzles are to be produced additively. An increase to 100,000 units is planned for five years’ time. As in the case of GE Inspection Robotics, the benefits more than make up for the high investment costs. The printed nozzle is one third lighter and thus saves fuel in flight operation. Furthermore, the optimised geometry of the nozzles, which are produced in one piece rather than 20 individual parts, also considerably improves the injection performance.

And HP has recently been supplying 3D printers under the name “Jet Fusion” with a new “Voxel”-based printing technology, which works faster by several factors while producing parts with more precise dimensions and greater mechanical stability.

The aircraft engine manufacturer GE Aviation is also playing a key role in the technology's rapid development. The Americans are shaping up metal 3D printing for mass production with a factory for engine injection nozzles. 100,000 units are to be produced annually by 2020. As in the case of GE Inspection Robotics, the benefits more than compensate for the investment costs. A printed nozzle is more lightweight by a third, thereby saving a corresponding amount of fuel during flight. What is more, the optimised geometry of the nozzles manufactured in one piece instead of 20 individual parts significantly improves the injection performance.

In fact the entire group is opting for 3D printing: In September 2016, General Electric took over two 3D printing companies from Sweden and Germany for a total of 1.4 billion dollars and plans to establish a 3D printing business with turnover in the billions by 2020.

Engineering is taking command

“3D printing is changing not only the products but also the supply chain,” stresses Baldinger. “Manufacturing and purchasing are intermeshed much more closely with engineering, while customers are involved more intensively in product development.” This enhanced role played by engineering suits the qualities of Swiss manufacturers. All the more so, as the new opportunities shift the focus from costs towards value added, as the example of GE Inspection Robotics clearly illustrates. The additive methods are therefore a response to one of the biggest challenges for Swiss workplaces.

From model construction to additive manufacturing

3D printing has already long been in use in industry for the rapid production of models and functional prototypes. For this, a plastic printer builds up designs created in CAD programs directly layer by layer. The additive manufacturing methods are now raising this rapid prototyping to the level of quality required for production with regard to regarding tolerances, homogeneity and durability.

Depending on the material, various printing techniques are used for this. The broadest range is available for plastics. These can be built up using various polymerisation techniques, bonding or various melting methods. Ceramic can be bonded or sintered using lasers. In a similar way, metal parts are built up in a metal powder bed by means of selectively melting a thin metal powder layer using lasers or electron beams. The accuracy of metal printing is currently around 0.02 millimetres and the maximum size of the printed parts corresponds to a cube with an edge length of around 60 centimetres. The density of up to 99.9 per cent and the processing properties correspond to those of welded parts.

The greatest cost factor in all additive procedures is the printing time. Every acceleration of the technology therefore directly influences the price. The greatest advantage is in the much greater geometric freedom. Thanks to this, for example, an additively manufactured seatbelt buckle made from titanium can be made 55 per cent lighter. In the Airbus 380, this reduces the total weight by 72.5 kilograms. Across the entire lifespan of the aeroplane, this allows a saving in fuel of around two million francs.

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