The effect of multi-beam strategies on selective laser melting of stainless steel 316L

With increasing industrial application of additive manufacturing technologies, such as selective laser melting, the requirements concerning the processes' capabilities like productivity, robustness, part quality and the range of processable materials are increasing as well. But due to high cooling rates, high thermal gradients and a layer-wise processing, parts produced by selective laser melting are subject to different kinds of defects. These defects commonly lead to high porosity, distortion, cracking and rough surfaces. But when a second beam is used to heat the vicinity of the melt pool a homogenization of the temperature field, a reduction of the cooling speeds within the melt pool and in its vicinity as well as an improved wetting behavior is possible. A proof of concept is shown, discussing general trends and possibilities, like increased surface qualities or dense microstructures with low amounts of remelting, when these strategies are elaborated.