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sts.components.contact.mr.placeholder Sebastian Webel
Mr. Sebastian Webel

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Pictures of the Future
The Magazine for Research and Innovation
 

Additive Manufacturing

How Power Plants Can Benefit from 3D Printed Parts

3D printing enables parts to be produced at practically the push of a button and designs to be changed with only a few clicks of a mouse. Moreover, previously impossible designs can now become a reality.

At its plant in Finspong, Sweden, Siemens manufactures parts for gas turbines. It does so using 3D printing, which opens the door to on-the-spot production of previously impossible designs, thus making new business models, especially for services, possible.

Although Östergötland is a flat region, a hill rises up from the surrounding landscape in Finspong, a half hour’s drive west of the old industrial port city of Norrköping. Because the hill is a granite block, the plateau at its summit is an ideal foundation for the production of heavy industrial equipment. In the 1980s, a production hall was built here for gas and steam turbines. Siemens acquired the factory and office building in Finspong more than ten years ago, when it bought a business unit from Alstom. Siemens Industrial Turbomachinery AB has been manufacturing medium-size industrial gas turbines here since 2003. The term “medium-size” is relative, however. The heaviest model produced here, the SGT 800, weighs 290 metric tons and generates up to 54 megawatts of electricity – enough for a large industrial facility.

During a tour of the factory, one can see assembly workers opening the covers of an SGT 800 turbine to install the 30 gas burners that drive its turbine blades. The matt gray burners are stored on carriages, where they are ready for installation. Despite their complex design, they have almost no visible welding seams. “3D printers will soon produce the complete upper half of these burners,” says Andreas Graichen, who heads a team of additive manufacturing experts at Siemens in Finspong.

A 3D printing workshop in Finspong. Here, several selective laser melting (SLM) machines turn metal powder into new burners, layer by layer.

Sixty Percent Hydrogen

Additive manufacturing, which is also referred to as 3D printing, represents a veritable revolution for gas turbine production — as well as for many other industries. That’s because it enables parts to be produced at practically the push of a button and designs to be changed with only a few clicks of a mouse. Moreover, previously impossible designs can now become a reality —intertwined hollow parts, for example, or seamless double-walled structures with a honeycomb filling.

A welding engineer by trade, Graichen, who came to Finspong more than 20 years ago, points to a recently developed burner head. Thanks to 3D manufacturing, the object has an outer wall punctuated by gaps, and inner areas characterized by frame-like structures that are used to test alternative fuels — primarily hydrogen or synthesis gas. These gases are often generated during industrial processes as a waste product. Although plant operators would like to use them, they have not been able to do so because the gases would have to be uniformly mixed by the burners. Now, however, that has become possible thanks to the frame-like structures. The structures enable the new burners to add up to 60 percent hydrogen to the natural gas – a revolutionary feat. Only a few percent were previously possible, because the old heavy-industry methods such as casting and welding were unable to produce the structures needed for higher admixtures.

New Life for Remanufactured Parts

Because of its flexibility, 3D printing is spreading into more and more sectors. When Vladimir Navrotsky, who is the technology director for the distributed power generation service sector at Finspong, began conducting experiments with additive manufacturing in 2008, the technology was still very expensive and could only be used to create prototypes for testing. But Navrotsky wanted to use the technology to restore worn parts and eventually produce entire components. Both of these goals have now been achieved and integrated into the Finspong plant’s production process.

The customer can request the latest designs to be printed onto the burner heads. The result is a major increase in efficiency.

Navrotsky’s team has been remanufacturing used burner heads since 2013. Service technicians remove the burner heads from the gas turbines after about 30,000 hours of operation and send them to Siemens’ Finspong facility. There, technicians remove the upper two centimeters of the worn burner heads and simply reprint this layer onto the parts. After less than 20 hours in a 3D printer, the old burners are as good as new and ready to be reinstalled. Because downtimes are costly, the technicians immediately replace the old burners with other parts that have already been remanufactured.

In addition to the advantages of on-the-spot refurbishment, remanufactured parts generally enable plant operators to achieve higher energy yields. That’s because “Efficiency can rise by up to one percent,” says Navrotsky. Another improvement is the use of new materials for the printing process. In fact, powder manufacturers can now supply almost any material composition imaginable, including highly durable nickel-based materials that can withstand a temperature of 1,500 degrees Celsius at the burner tips.

Vladimir Navrotsky, technology director for the distributed power generation service sector at Finspong.

Spare Parts from the Cloud

According to Graichen, additive manufacturing opens the door to a fully digitized value chain. He explains what he means as follows: Although many manufacturing steps are already digital, they form isolated digital islands. What is needed is the automated linking of these islands to create a totally digital value chain. Once digital production control processes have been successfully implemented at several traditional workshops, production could conceivably be carried out regionally, in proximity to the customer. The distance between the customer and the manufacturer will no longer be an obstacle in the fully digital production chain of the future. That’s because the shipment of finished parts could be replaced by the transmission of data, which can be quickly and securely sent to even the remotest points on earth.

But what happens if such data isn’t available – for example in the case of decades-old facilities for which there are neither spare parts nor digital design data? In order to generate this data, the original parts could be subjected to a 3D X-ray scan like those created by hospital CAT scanners. The resulting data set would then be used to control the production of new parts using additive manufacturing. This would make completely new business models in the services sector possible, says Graichen: “Digital geometric and manufacturing data might become even more valuable than hardware, once the printing of metal parts becomes as common as printing on paper is today.”

Bernd Müller