## 3 Results and Discussion
### Discussion
Firstly, it is a non-thermal process, which significantly reduces the risks of surface oxidation, microstructural alteration, or the formation of heat-affected zones--issues commonly associated with laser-based methods. This makes MAF particularly attractive for materials sensitive to thermal degradation, such as the nickel-based superalloys used in the aerospace and energy sectors. Furthermore, in contrast to electrochemical methods that require complex electrolyte management and raise environmental and safety concerns, MAF is mechanically driven and does not involve corrosive media. Although some polishing techniques, like ultrasonic cavitation or electro-polishing, may deliver lower roughness in less time, they often face limitations regarding accessibility to complex geometries or internal features. In this regard, MAF demonstrates superior adaptability to intricate surface profiles, especially when integrated with planetary kinematics. Thus, while MAF may not yield the lowest roughness values among the surveyed technologies, it achieves a balanced performance, combining acceptable surface quality with excellent process safety, environmental friendliness, and geometrical flexibility. It is also worth highlighting the flexibility of the employed methods--both vibratory finishing and MAF; due to their operating principles, they allow the tool to conform to the shape of the workpiece surface. This feature makes them particularly attractive for finishing components produced using additive manufacturing technologies such as LPBF, where complex geometry and limited accessibility to surfaces are common. The ability to achieve high-quality finishing without the need for rigid and dedicated mechanical tooling represents a significant advantage of the discussed approach. Therefore, the use of hybrid processing combining vibratory and MAF techniques fully leverages the potential of 3D printing in the design and production of geometrically complex components, offering high surface quality and the potential for further optimization of operational parameters. Beyond the achieved improvements in surface roughness, the magnetic abrasive finishing (MAF) process is likely to induce additional beneficial modifications to the surface layer that were not assessed in the current study but warrant future investigation. The literature suggests that MAF processes, due to their mechanical and localized nature, often introduce compressive residual stresses in the surface layer, which are known to significantly enhance fatigue strength and resistance to crack initiation. Additionally, the repeated plastic deformation of the surface during abrasive interaction is expected to cause strain hardening, potentially resulting in an increase in surface microhardness, which would directly improve wear resistance and tribological performance. Future research should therefore focus on the comprehensive characterization of these effects, including microhardness depth profiles, residual stress analysis (e.g., via X-ray diffraction or hole \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Method** & **Material** & \
\begin{tabular}{c} **Initial Roughness** \\ **[\(\upmu\)m]** \\ \end{tabular} &
\begin{tabular}{c} **Final Roughness** \\ **[\(\upmu\)m]** \\ \end{tabular} & **Time [min]** \\ \hline Overpotential Electrochemical Polishing [26] & Inconel 738 LC & Sa \(\approx\) 9–10 & Sa 2.5 & 30 \\ Advanced Electrochemical Polishing [27] & Ti6 Al4V & Ra \(\approx\) 11.5 & Ra 1.5 & 15 \\ Abrasive Fluidized Bed Maching [28] & Inconel 718 & Ra \(\approx\) 12.3 & Ra 0.9 & 360 \\ Ultrasonic Cavitation Abrasive Finishing [29] & Ti6 Al4V & Ra \(\approx\) 11.12 & Ra 0.25 & 15 \\ Laser Polishing [30] & Inconel 718 & Ra \(\approx\) 7.5 & Ra \(<\) 0.1 & \textless{1} \\ Laser Polishing [31] & 18 Ni maraging steel & Ra 2.7 \(\div\) 6.4 & Ra 0.6 & \textless{1} \\ Laser Polishing [32] & 316L Stainless Steel & Sa 11.81 & Sa 2.67 & \textless{1} \\ Vibratory machining + MAF [current research] & Inconel 939 & Ra 5.6 & Ra 0.81 & 20 \\ \hline \hline \end{tabular}
\end{table}