Streamlined frameworks for advancing metal based additive manufacturing technologies

Metal-based additive manufacturing (AM) technologies such as selective laser melting (SLM) have seen successful applications in the gas turbine industry over the past years. The rapidly growing demand in AM requires in-depth knowledge of the process, materials and design for additive manufacturing (DFAM). However, the material characterization and process development are highly specific to a particular AM system, even for a number of standard alloys such as IN718 that are suitable for gas turbine applications. When the AM system changes or a new material becomes available, the whole development workflow needs to start almost “from scratch”, which consumes considerable time and effort. To address these issues, Siemens Power&Gas has established cross-divisional competence centers for AM to enhance collaborative material and process development. The paper describes this framework and its effectiveness in streamlining the AM process and materials development. To close the design and manufacturing process chain, it is also critical to ensure that the full AM potential is accessible in design stages. In this paper, a DFAM framework is proposed to drive the design paradigm shift to AM. In the framework, a complete DFAM process is defined based on existing studies of Siemens gas turbine applications. By integrating a set of DFAM methods, tools and considerations into the current gas turbine design processes, the AM-driven product design is enabled. We use Siemens large gas turbine applications to demonstrate the development and industrialization of AM using the frameworks. The benefits in reducing cost, expediting time to market, improving component performance and enabling new design freedom will be highlighted. INTRODUCTION With the increasing demand for higher gas turbine efficiency, the design margin allowed by existing manufacturing processes is constantly squeezed. To open up new design space, Siemens has been exploring metal-based additive manufacturing (AM) technologies such as selective laser melting (SLM). In general, these processes make a part by melting metal powder layer by layer using a high energy density heat source. Comparing to the conventional subtractive manufacturing processes, the metal-based AM processes are capable of producing radically different designs like lattice structures and internal winding channels. The new design space can be leveraged to solve engineering problems that are otherwise highly challenging. Moreover, since the AM processes work directly with the 3D model and produce near-net shapes, the design-to-product process chain is shorter than conventional manufacturing methods. This allows rapid prototyping and manufacturing that are critical to the fast design iterations. Due to these unique characteristics, metal-based AM processes have the potential of significantly reducing product cost and lead-time, especially for parts with relatively smaller batches. However, the wide adoption of AM in gas turbine product development is quite challenging mainly due to two reasons. First, the strict design requirements call for solid understanding of the designated AM process and material properties. However, the AM process development and material characterization workflow is lengthy and costly given limited existing knowledge. In addition, Siemens internal experiments have shown a strong specificity of the