# 3D Printed Microfluid Separators for Solid/Liquid Suspensions
## 4 Conclusions  
Manufacturing monitoring technologies are key to flow chemistry, where they facilitate the efficient separation of particles, ensuring that production yields particles with specific sizes and shapes, which supports efforts to minimize waste through enhanced process control. In this study, spiral separators were fabricated using both SLA and FFF 3D printing technologies. Three types of microfluidic devices were used for solid/liquid separation: the SLA 1 (square cross section) separator, the SLA 2 (circle cross section) separator, and the FFF (circle cross section) separator, all of which have a spiral internal structure composed of eight turns. Powder separation was conducted at flow rates of 200 mL min\({}^{-1}\), 250 mL min\({}^{-1}\), and 300 mL min\({}^{-1}\). Subsequent to the separation procedure, an analysis was conducted on the mass of the powders retrieved and dried from the external (Outlet 1) and internal (Outlet 2) outlets of the separators. By normalizing the powder mass at the outlets of the separator, the most significant difference in mass between Outlet 1 and Outlet 2 was observed for baby powder separation through the SLA 1 separator and operated at a flow rate of 200 mL min\({}^{-1}\). In the case of calcium carbonate, the most significant difference in mass was also with the SLA 1 separator at a flow rate of 200 mL min\({}^{-1}\), while for quartz sand, it was with the FFF separator, again at a flow rate of 200 mL min\({}^{-1}\). The only significant anomaly was the clogging of the SLA 1 separator at a flow rate of 250 mL min\({}^{-1}\) with quartz sand, which resulted in failed testing. The differences between Outlet 1 and Outlet 2 indicate that while both outlets effectively separate larger particles from the initial distribution, Outlet 1 is superior at isolating bigger particles. This distinction is critical for applications that require precise control over particle size distribution. For instance, industries relying on bigger particles for filtration or abrasive applications might prefer the output from Outlet 1, whereas Outlet 2 could be more suitable for applications that require slightly smaller particles. This phenomenon can be attributed to the effect of centrifugal force, where particles with greater mass exhibit increased inertia and thus display different movement patterns compared to smaller par \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Before Separation** & **Outlet 1** & **Outlet 2** \\ \hline \(d_{\text{mode}}\) (\(\upmu\)m) & 352 & 393 & 393 \\ \(d_{50}\) (\(\upmu\)m) & 280 & 401 & 369 \\ \(d_{3,2}\) (\(\upmu\)m) & 803 & 890 & 624 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: PSD parameters introduced as characteristic diameters for quartz sand in FFF separator at 200 mL min\({}^{-1}\). ticles. Flexible control systems are critical in flow chemistry, allowing for the adjustment of flow rates to improve the efficiency of separating particles by size, making the process more adaptable and minimizing waste. Upon comparison of the values for the powder particles before and after separation, a notable discrepancy was observed in terms of particle size increase. This discrepancy is attributed to the formation of agglomerates. Although these separators did not achieve complete solid/liquid separation, the methodology shows great promise. We believe that with further research, the efficiency can be significantly enhanced. Advances in additive manufacturing technologies and the development of new separator designs have the potential to lead to substantial improvements in separation efficiency. Effective intelligent preparation and maintenance in flow chemistry are vital for achieving optimal particle separation, ensuring that particles are produced with consistent quality while minimizing waste and enhancing the stability of the manufacturing process. M.-P.M. Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Validation, Visualization, Writing--original draft, Writing--review and editing. K.Z.