# Characterization of Deburring by Abrasive Flow Machining for AL6061
## 6 Conclusions  
In this study, deburring was conducted by AFM with a low-viscosity abrasive medium at high-flow speeds. [PERSON] (2018) previously suggested that deburring performance is affected by the local curvature of the streamline near the burr edge and wall shear stress. It was expected that flow speed would also have a significant effect, and [PERSON]'s objective function was supplemented with \(V^{2}\), representing the kinetic energy of the abrasive particles near the burr edge. To observe and verify this concept, preliminary deburring tests were performed on a set of milling workpieces along with CFD simulations for planar flow. The experiments were performed in six stages, and deburring progress was observed. The progress was characterized by the volume of material removed from the ideal burr edge. It was confirmed that the progress soundly correlates with the new objective function value, as shown in Figures 16 and 17.  
Under the assumption that the flow component is tangential to the burr edge has relatively little contribution to the deburring, the new objective function has a potential for general applications beyond the planar flow. Along this line, the application of the new objective function to the erosion of the burr edge is formed by two drilled holes of 12 mm diameter, intersecting at 30\({}^{\circ}\) with a 10 mm offset. Such configuration generates very  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Average Objective Function Values**} & \multicolumn{2}{c}{**Deburred Area**} \\ \cline{2-5}  & \(f_{ob,\,Netp}\) & \(f_{ob,\,Kim}\) & **56 km** & **112 km** \\  & **(Nm/s\({}^{2}\))** & **(N/m)** & **(mm\({}^{2}\))** & **(mm\({}^{2}\))** \\ \hline Position 1 & 6286.7 & 22.4 & 0.033 & 0.158 \\ Position 4 & 4043.2 & 54.7 & 0.022 & 0.100 \\ Ratio (P1/P4) & 1.55 & 0.41 & 1.50 & 1.58 \\ \hline \hline \end{tabular}
\end{table}
Table 11: Average values of the objective functions and the sectional deburred area measured at positions 1 and 4 for flow lengths of 56 km and 112 km.  
Figure 29: New objective function value vs. position on the burr edge (Figure 24).  
thin burr edges that are most favorable to burr formation. For observations, two positions (1 and 4) along the burr edge were selected, representing the thinnest and thickest sections. From the CFD simulations, the ratio of the new objective function values at positions 1 and 4 was 1.55, as listed in Table 11. From the experiments, the ratios of the actual deburrred area for the first and the second stages of deburring each, up to 56 km and 112 km of flow lengths, were 1.50 and 1.58, respectively. The new objective function thus seems to have a potential, with reasonable accuracy, for industrial applications for predictions and optimizations of deburring processes based on CFD simulations.  
Conceptualization, K.-J.K. and K.-H.K.; methodology, K.-J.K. and Y.-G.K.; validation, K.-J.K.; formal analysis, K.-J.K. and K.-H.K.; investigation, K.-J.K. and Y.-G.K.; data curation, K.-J.K.; writing--original draft preparation, K.-J.K.; writing--review and editing, All; visualization, K.-J.K.; supervision, K.-H.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data generated in this study are freely available.  
The authors declare no conflict of interest.