## 2 Materials and Methods
### Process of the Optimization of FDM Printing  
The effectiveness of the FDM process depends on selecting suitable materials and precisely tuning the printing parameters, both of which are crucial for achieving smooth surface finishes and accurate results [13]. In the context of this research project, polylactide (PLA) was selected as the optimal material for 3D printing for several compelling reasons. PLA is widely used in FDM 3D printing due to its affordability, accessibility, and favorable properties, making it ideal for various applications. It has a low printing temperature (180 \({}^{\circ}\)C to 230 \({}^{\circ}\)C), reducing energy demands and simplifying temperature control. Additionally, PLA is biodegradable and made from renewable resources like cornstarch, offering an eco-friendly alternative to materials like ABS. The technical properties of PLA (as shown in Table 2) include a favorable dimensional stability and minimal warping risk, which are crucial for the precise and uniform printing of objects, particularly in the context of critical parameters such as the layer height and printing speed. Its strength and stiffness render it a suitable material for a plethora of applications, particularly in the domain of prototyping and in contexts where high thermal or mechanical loads are not a prerequisite. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Key Steps in the FDM Process**} \\ \hline Digital Model & The process begins with the creation or acquisition of a digital 3D model, typically designed using Computer-Aided Design (CAD) software. This model is then converted into a suitable file format, such as STL or OBJ, which can be interpreted by the slicing software [32]. \\ \cline{2-3} Preparation & Slicing software segments the 3D model into thin horizontal layers and generates a G-code file that contains detailed instructions for the printer, including tool paths and specific printing parameters [32]. \\ \hline \multirow{4}{*}{Printer Setup} & Filament Loading & The chosen filament is loaded into the printer, where it is guided through the drive gear mechanism. The design of these gears ensures the optimal grip and consistent feed of the filament [33]. \\ \cline{2-3}  & Temperature Settings & The printer’s extruder and build plate temperatures are set according to the specific requirements of the filament material. These temperatures typically range between 250 \({}^{\circ}\)C and 500 \({}^{\circ}\)C, depending on the type of thermoplastic being used [13]. \\ \hline \multirow{4}{*}{Material Extrusion and Layer Deposition} & Material Melting & The filament is heated in the liquefier, transitioning from a solid to a molten state. The molten material is then extruded through a precisely controlled nozzle [34]. \\ \cline{2-3}  & Layer-by-Layer & The extruder deposits the material layer by layer on the build platform. Each layer solidifies and adheres to the previous one, gradually building up the object. The layer thickness, ranging from 0.1 mm to 0.4 mm, is adjustable to balance the print resolution and speed [34]. \\ \cline{2-3}  & Build Platform Movement & After each layer is completed, the build platform lowers (or the print head raises) by the layer height, allowing the next layer to be deposited [35]. \\ \hline \multirow{4}{*}{Post-Processing} & Upon the completion of the printing process, the object may require post-processing. This can involve the removal of support structures, surface finishing techniques such as sanding or polishing, and other treatments to enhance the mechanical properties or aesthetics [35]. \\ \cline{2-3}  & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: FDM process. It is similarly important to recall the principal parameters associated with the FDM technique, which encompass the layer thickness, orientation, filling density, structure orientation, temperature, and speed. Incorrectly setting these parameters can result in the occurrence of undesirable outcomes, such as the over- or under-extrusion of the plastic material [36].