To use SLM economically in industrial or series production, operators need higher productivity in the process, increased flexibility in view of available building space as well as reproducible component quality. The productivity is determined, on the one hand, by the achievable melting rates and, on the other, by the non-productive time of the process.
In addition, researchers have still not mastered how to process materials that are difficult to weld and susceptible to cracking. For applications where safety plays a critical role, an inline process control or such a strategy is necessary so that an assessment can be made about the quality of the component without it needing subsequent testing.
To increase both productivity and available building space, the industry is currently pursuing several approaches. For example, the Fraunhofer ILT uses a two-beam optical system it developed, which has different laser power outputs (up to 2 kW) and beam diameters for various component areas. This system allows the build rate to be increased significantly, but requires the optical system as well as the control software to be adapted.
Larger building space, in turn, can be achieved by arranging several optical systems in parallel or using a single, movable optical system, whereas the specific consequences – higher costs due to additional optical components or longer building time for large parts with a single optical system – have to be taken into consideration. Moreover, more complex gas flow systems have to be developed to sustain a sufficient protective atmosphere.
Individual material classes, for example heat-resistant nickel and cobalt base materials as well as hard metals can only be processed crack-free when the building platform is preheated to high-temperatures. Such temperatures range from 800 to 1200 °C and can only be reached by the facilities in the laboratory of the Fraunhofer ILT.