# Parameter Optimisation in Selective Laser Melting on C300 Steel  
[PERSON]  
1 Structural Integrity Group, Universidad de Burgos, Escuela Politecnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain 1  
[PERSON]  
1 Structural Integrity Group, Universidad de Burgos, Escuela Politecnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain 1  
[PERSON]  
1 Structural Integrity Group, Universidad de Burgos, Escuela Politecnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain 1  
[PERSON]  
1 Structural Integrity Group, Universidad de Burgos, Escuela Politecnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain 12 Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Escuela Politecnica de Ingenieria de Gijon, University of Oviedo, Campus de Viesques, 33203 Gijon, Spain 2  
[PERSON]  
3 Samylabs, C/Astintze 6A, Oficina 001, 48160 Derio, Bizkaia, Spain 3  
[PERSON]  
1 Structural Integrity Group, Universidad de Burgos, Escuela Politecnica Superior, Avda. Cantabria s/n, 09006 Burgos, Spain 1  
generalised the process to different metallic materials, such as copper alloys, aluminium and tungsten [10].  
The microstructure generated in the material has an intrinsic characteristic morphology, as a consequence of the superposition of successive molten layers of a few tens of micrometres, including the likely presence of defects or pores mainly at the melting edges. An interesting review of the mechanisms for defect formation in materials manufactured by SLM can be found in the work of [PERSON] et al. [11].  
In this sense, it is necessary to study in depth the printing parameters to obtain materials with a microstructure that gives them good properties, similar to those that can be obtained with other conventional manufacturing methods. Especially in those materials that are newly considered for Additive Manufacturing, such as C300 steel, commonly used in mould tooling in the automotive sector.  
The printing parameters are numerous, but three critical variables can be highlighted: laser power, laser speed and hatch spacing. These are the parameters studied in this research, representing the base of the considered design of experiments and the corresponding response surfaces. Design of experiments is a statistical technique to identify and quantify the most important factors in an experimental study. It has been used successfully in many fields since the early 1920s [12; 13; 14; 15]. This technique facilitates the optimisation of the number of experiments performed to determine the influence of some input variables on the experimental outcome. This design is very important when tests are costly, either in a computational or economic sense, as well for minimising the duration of experimental campaigns.  
For these reasons, the main objective of this paper is to optimise some of the key parameters in this process, such as laser power, laser speed and hatch spacing. These variables are essential for the production of parts with good resistance. In order to do this, tensile tests were performed in 3D printed specimens, and then elastoplastic properties were extracted, organised and analysed using design of experiments based on the response surface methodology.