Over the years the industry has been tried to optimize processes in order to save money, time and improve several ratios. In the last years, Additive Manufacturing (AM) has raised its popularity because it allows to build parts faster and in a more autonomous way than conventional methods. Moreover, with this technique it is possible to build complex structures and optimize the whole process while maintaining good mechanical properties.

LPBF is an important technique that is used in the AM industry and specifically in this thesis this technique coupled with a nickel based superalloy, Alloy 718, was studied. This material is mainly used in the aerospace industry because maintains its mechanical properties until 650ºC.

The aim of this project has been to study different LPBF build parameters with an objective to increase the build rate, because with increased build rate the the build time can be reduced , thus saving money. However, in this project the aim is not just to find the combination that gives the best build rate, because one has to take important factors like the defect density, defect morphology, melt pool size and hardness into consideration. For this reason, in this thesis project the final aim is to find the parameters with the best build rate while maintaining low porosity so that future mechanical properties are not deteriorated.

Using the different machines provided by Innovatum Science Park and University West the samples were prepared for further study. The samples were received as as-built samples and prepared for their further analysis. 

After completing all the steps, ImageJ software was used for the defect study and to measure some melt pool size for their further analysis, Excel to get the main results and do some statistical analysis for the future conclusions and the software MODDE in order to improve the model that shows the relation between the main parameters of the laser power bed fusion with the main characteristics of the material.

Finally, after doing the full analysis for the different parameters and using the software to predict and check results the main results or conclusions were obtained. It was discovered that increase the layer thickness has not a negative impact in the porosity or lack of fusion values in spite of what could be thought at the beginning. For this reason, the best results were in the DOE 120 micro m with the highest combination of hatch distance and scanning speed, whereas the laser power has not a significant influence in the build rate. The factor that has had more influence in the porosity was the hatch distance, so it is important to be careful with this parameter if it is tried to increase the build rate by increasing it. Further, for the same scan speed, if it is used a highest value of laser power the porosity will not get as worse as if it is used a lower one. 

As further study, it would be interesting to create a prediction model for 150 micro m layer thickness and then do it in the lab to check if the results agree. If it can be used this layer thickness the improvement would be awesome because it will save lot of time and money for the built parts in the industry. Moreover, it would be attractive to study the influence of the post treatments for the main characteristics of Alloy 718