Mike Scott visits Siemens’ Distributed Generation Plant in Finspang, Sweden to see how 3D printing is transforming the ways in which the company approaches innovation
Most of readers will be no strangers to the revolutionary implications of 3D printing. Even oil and gas, typically a slow adopter, is beginning to catch on in light of its ability to improve maintenance schedules and component inventories. It is also having a profound effect on mechanical design, in everything from tiny components to turbo-machinery.
One example of this can be seen at the Sweden-based gas turbine unit of the German industrial conglomerate Siemens. The company has started using 3D printing to manufacture components for its products, which are widely used in the oil and gas sector as a power source for compressors and pumps, as well as for power generation. 3D printing, also known as additive manufacturing (AM), creates products by depositing layers of ground metal or plastic to a template, lasering that material into place and repeating the process to build the required product. Much of the focus on AM has been on the consumer side but real benefits are being seen in industry.
Siemens has described the technology as a “game-changer.” Although it lists multiple benefits, one of the most startling is that, in some cases, the technology has enabled a 75% reduction in the time taken to bring some products to market. Parts which used to take a couple of years to bring to market can now be made available within months, even weeks.
In addition, 3D printing offers increased design flexibility, quality and efficiency. There are environmental benefits, too, with greenhouse gas (GHG) emissions reportedly cut by 30% and resource use by 63%.
One of the main benefits of AM is that new designs can be visualised, produced and tested quickly and cheaply, leading to a surge in engineering innovation. “At least 30% of the design of many components is determined by the restrictions of the manufacturing process,” said Dr Vladimir Navrotsky, chief technology officer for Siemens’ Distributed Generation Service based in the small town of Finspang, Sweden. “AM opens up new design possibilities. Simply by designing specifically for Additive Manufacturing automatically creates more innovation.” In part this is because designers now have the freedom to try something, fail and have another go without costing the company any money, whereas previously the cost and time of bringing a component to production led to an innate conservatism among designers. It used to take a year to develop a gas turbine blade, and if it was not right it would take another year to correct.
It is also because AM opens up possibilities that traditional manufacturing could not offer. Now, says Thorbjoern Fors, CEO of Siemens’ Distributed Generation Service, “if you can dream it, you can print it”.
For example, Siemens has also been able to cut the weight of its gas turbine blades by replacing solid turbine blades with 3D-printed ones. These use a lattice design that was simply not possible to make using traditional manufacturing techniques. The lattice structure uses less material (and so takes less time to print) while maintaining strength. This means that less energy is required to turn the blades but it also aids cooling, which dramatically increases the lifetime of the blade. “If you can cool the metal by 10°C, you increase its life by half,” Navrotsky pointed out.
Meanwhile, the burners for its turbines, which used to be made up of 13 different parts that had to be welded together, can now be 3D-printed as one component, saving considerable amounts of time, energy and resources. Moreover, changes to the design of the burner nozzle that 3D printing makes possible mean the turbines are now capable of burning up to 60% hydrogen, allowing customers that produce a lot of hydrogen as a by-product, such as refiners and chemical plants, to use it to produce energy rather than waste it.
With the prospect of hydrogen becoming a more important part of the gas network in future, this could be a beneficial and Siemens is aiming to tweak the design so that it can burn 100% hydrogen.
Repair or replace
3D printing is not only being used to manufacture tailor-made products; it can also be used to enhance mass-produced articles by adding specific, personalised components. And spare parts can be produced when and where they are needed, eliminating the inventory costs of keeping supplies on hand and cutting logistics costs. Not only that, but AM also allows for niche repairs. Parts can be printed to replace only the part or component that needs replacing, again saving cost and resources.
For example, in Siemens’ turbine blades, the tips are subject to the biggest stresses and therefore need more frequent replacing, while the rest of the blade is still fit for use. Instead of replacing the entire component, the company can now cut off the tip and print a replacement on to the old blade.
Siemens is looking to ramp up its use of AM significantly, although it acknowledges that it is not suitable for all components. “There are components where traditional manufacture is still competitive,” Fors explained. “For now, AM works best for complicated structures, particularly where weight is important.”
Nonetheless, Navrotsky adds: “Over the next five years, I believe this technology will allow us to cut costs by 50%. Designing for Additive Manufacturing automatically creates more innovation. We are not working with AM because it is sexy but because it is an extra tool to multiply the knowledge we have in component design.”