## 4 Conclusions and Outlook  
This study experimentally investigated the influence of applying different printing process parameters within the bulk of the same part in order to induce and tailor surface as well as mechanical properties within one component. To achieve this, surface roughness and hardness measurements were systematically acquired by conducting a DoE and regression analysis. After evaluating the results, it can be said that the most important parameters were laser power, scan speed, and their interaction, which led to the creation of parts with different functional performances at different locations. The following are specific conclusions that can be made:  
1. The linear energy density applied by the laser played a major role in the top surface roughness with high surface roughness seen in low energy densities, caused by insufficient melting. The surface roughness decreased as a more stable melt pool was reached when the LED increased. However, after a point, the surface roughness increased once again due to other printing defects that manifested due to the high LED.
2. Surface roughness on the side surfaces was seen to be consistent as they were mostly affected by the chosen layer thickness, which was kept constant for all the trials.
3. The hardness on the side surface was highly unpredictable due to the unstable nature of measuring the hardness created due to the layers.
4. For the hardness on the top surface, the hardness remained consistent for the various LEDs tested, with the scan speed seen as the most influential parameter.
5. Low-LED samples had lower density than the higher-LED samples, which was consistent with the resultant hardness.  
This research work has proven to be a step towards integrating multi-functionality and functionally graded materials within one part through gradually tuning the process parameters across a component. In order to obtain a deeper understanding of said topic, it could also be helpful to investigate the microstructure of the parts and shed some light on the grain structure and size, which will be the topic of future studies.  
Figure 20: Microscopic images of the polished surfaces of (**a**) low LED test piece (0.23 J/mm), (**b**) Reference LED test piece (0.33 J/mm) and (**c**) high LED test piece (0.50 J/mm).  
**Author Contributions:** Conceptualization, A.E. and A.C.; methodology, A.E., A.C., S.G.S. and S.S.; software, S.S.; validation, A.E., A.C. and S.S.; formal analysis, A.C., A.E. and S.S.; investigation, S.S.; A.C. and A.E.; resources, S.G.S.; data curation, S.S., A.C. and A.E.; writing--original draft preparation, S.S., A.C. and A.E.; writing--review and editing, A.E., A.C. and S.G.S.; visualization, A.E., A.C. and S.S.; supervision, A.E. and S.G.S.; project administration, S.G.S.; funding acquisition, S.G.S. All authors have read and agreed to the published version of the manuscript.  
This work was carried out with the support of the Karlsruhe Nano Micro Facility (KNMFi, www.knmf.kit.edu (accessed on 15 June 2022)) a Helmholtz Research Infrastructure at Karlsruhe Institute of Technology (KIT, www.kit.edu, (accessed on 15 June 2022)) and under the Helmholtz Research Programme MSE (Material Systems Engineering) at KIT.  
Not applicable.  
The authors also acknowledge the support of the Metal Industries Research and Development Centre, Kaohsiung, Taiwan. The authors acknowledge the support of [PERSON] of the Institute for Applied Materials (IAM) of the KIT who helped conduct the Archimedes test of the AM samples. The authors would like to acknowledge the support provided by the KIT-Publication Fund of the Karlsruhe Institute of Technology.  
The authors declare no conflict of interest.