Additive manufacturing, which is also known as 3D printing, covers a range of innovative production processes, the potential of which is currently being investigated and developed in various industries, including machine and vehicle manufacturing, the aerospace industry, and medical technology.
As well as plastic materials, there are now also processes, which enable 3D printing on metallic materials. Examples of these include Selective Laser Melting (SLM) and Electron Beam Melting (EBM). Depending on various factors such as lot sizes and material costs, these open up numerous benefits over conventional production processes along the whole value chain of a product, from development and production through to maintenance and service.
In general terms, 3D printing allows for tremendous benefits to be achieved in terms of speed, cost, and technology, potentially all of these at the same time. For example, improved speed can be achieved through shorter product development cycles, such as through rapid prototyping, or shorter lead times. Lower costs can be achieved through simplification and integration of engineering solutions, and having a positive effect on production. Enhancements in terms of technology can be achieved via more innovative and sophisticated designs. The availability of additive manufacturing demands that companies undertake a new way of thinking to make the best use of the possibilities that it offers.
MAN Diesel & Turbo is currently equipping gas turbines with 3D printed components. Uwe Lauber, CEO of the company, said: “As of now, we are the first manufacturer in the world to use complex 3D-printed metallic components, not only for test runs, but also for serial production. After a decade of research and development, we are proud that we have been able to make this significant step forward. The future of 3D printing allows us to offer our customers even better products.”
Dr Sven-Hendrik Wiers, Vice President of Gas Turbines and Head of Engineering for MAN Diesel and Turbo, said that the ability to combine what had previously been several components into a single item offered significant benefits. Because it avoided welding and fittings in the fabrication of what had previously been several items, the cost of production was reduced. In addition, in items such as compressor vanes, can be made with tighter tolerances, because of the additive nature of tolerances. This leads to the ability to reduce clearances, which in turn leads to reduced leakage through these clearances, and hence improved efficiency.
Another benefit offered by 3D printing is that it makes new geometries possible, either in rotating or stationary parts. This enables features such as cooling paths to be introduced where previously not possible. This, in turn, can enable the turbine to operate at higher temperatures, and hence at higher overall efficiencies.
A third benefit offered by 3D printing is in service and maintenance. If a part is partially broken, it may not be necessary to repair the whole part. It can be reprinted, retaining the portion that has not been broken. This provides a much better response time for the customer, it saves on costs, and it saves on the resources that are used.
Roland Herzog, Head of Material Technology in MAN Diesel & Turbo’s Turbomachinery Strategic Business Unit, said: “Additive manufacturing offers huge potential for our product range, especially when it comes to the production of gas turbine components. Additively manufactured guide vane segments that we are now incorporating into our type MGT6100 gas turbines have proven particularly suitable. The approval for serial production is the result of intense cooperation with specialised suppliers and development partners such as the Fraunhofer Institute for Laser Technology.”
In addition to compressor vanes, combustion chambers, burners, and hot gas components are suitable for production by 3D printing. Currently, MAN Diesel & Turbo uses the system for stationary parts, with rotating parts to come at a later stage.
Research into 3D printing
MAN Diesel & Turbo has been carrying out research into 3D printing for 10 years. This has enabled the company to turn a solid business case for the 3D printing of gas turbine components into serial production.
The company decided to focus development of 3D components on those cases where there was solid evidence that there would be tangible customer benefits for specific applications. This has now been achieved for the MGT gas turbine series, particularly with regard to cost reduction and lead times.
MAN Diesel & Turbo is integrating parts into its MGT gas turbine series that are additively manufactured by partner companies. The next step for the company is to extend in-house competence with 3D printing, while also working on extending the number of potential applications. This will enable the company to make improvements on even more components, and for more machines, systems and services.
Lauber said: “The standardised use of additive manufacturing is a strategic milestone for MAN Diesel & Turbo. 3D printing gives us clear competitive advantages in terms of our products supporting the decarbonisation of industry and power generation. The techniques considerably reduce the path from an innovative design to a finished product. The digital data from the R&D departments can be converted into better products more quickly than before, while customers are supported throughout the entire product lifecycle with 3D printing based services.”
3D printing enables the company to bring new designs to market much more quickly. It speeds up the process of getting the prototype through validation and into manufacturing. Reducing the time from concept to service results in savings, and it also results in the customer being able to more quickly benefit from the new design features. This brings significant cost savings, increases efficiency quickly, and provides the benefit to the customer as soon as possible.
In the future, the repeatability of component production will provide benefits. 3D printing will reduce production time, and increase the availability of spare parts.
Additive Manufacturing Centre
In order to exploit the potential of the technology even further, MAN Diesel & Turbo is currently investing in the MAN Centre for Additive Manufacturing, and product and location-independent expert centre based at the company’s turbomachinery works in Oberhausen, Germany. Design specialists, materials experts, and production engineers come together at “MANCAM” to extend the benefits of additive manufacturing to further components and products, such as compressor impellers or fuel nozzles for engines.
Herzog said: “We are currently investing some €2.6 million in order to utilize the numerous benefits of additive manufacturing along the whole value chain. As well as shortened development cycles, 3D printing gives more freedom for innovative, superior component designs, reduces production and delivery times, and enables us to produce spare parts on call.”
Design process
Wier said that developing new components needs designers to have a new mindset compared to traditional production methods. Just replicating old component designs does not enable the full benefits to be achieved.
The process is not very different to introducing other new technology. It is necessary to ensure that there is a secure supply chain in place, and that the quality and the process quality are up to standard. However, while the process is not very different, the designers need to be able to appreciate that they can take advantage of a number of different capabilities.
The ability to make use of MANCAM provides MAN Diesel & Turbo with what is in effect a virtual consultancy agency, which simplifies the logistics of getting a variety of experts together for a meeting.
3D printing is currently more expensive than conventional manufacturing techniques. As a result, the technique is not economically viable without adding value to the component. MAN Diesel & Turbo also makes use of the technique across its product range.
Future developments
MAN Diesel & Turbo plans to extend additive manufacturing to additional business cases, to more components and products. The company has pointed out that additive manufacturing opportunities are not limited to just gas turbines, and that it supplies other products and systems.
Looking further into the future, it is quite unlikely that every single component of a gas turbine will be additively manufactured. It might be more effective to use conventional manufacturing methods for specific components and circumstances.
For example, parts with high lot sizes or low complexity, or both, might be better suited to conventional manufacturing methods.
However, it is clear that the number of additively manufactured parts in gas turbines will increase. With the initial integration of such parts into serial production, MAN Diesel & Turbo has made a significant step to bringing about that future.