## 5 Conclusions  
There are many process optimization techniques available for improving the final product's quality in manufacturing goods. In this research, the implementation of the Taguchi method has allowed to identify that the printing temperature followed by layer thickness are the most influential process parameters to ensure a higher dimensional accuracy of wax patterns manufactured through FDM AM technology. In addition, to highlight important material properties of the wax-based filament, the next types of characterization experiments were performed with the following results:  
* Thermal analysis. Thermal analysis by means of DSC revealed a broad range of melting points which can identify the wax-based filament as a blend of waxes with a high probability of polyethylene being present in its content. In addition, no glass transition temperature was identified during the analysis, with a noticeable melting peak at approximately 110 \({}^{\circ}\)C. The absence of a Tg is advantageous since it eliminates the sharp transition from a solid to a soft state. Interestingly, the apparent melting peak  
Figure 8: Optical microscopic images of treated and untreated wax parts. The immersion time is indicated at the upper right corner of each image. at 110 \({}^{\circ}\)C identified by DSC analysis coincides with the optimal printing temperature found by the Taguchi analysis. This can be explained by the fact that one of the major components of the wax blend experiences phase transition from solid to liquid at 110 \({}^{\circ}\)C, resulting in lower melt viscosity that compromises melt stability. If we consider that the actual temperature of the melt is always lower than the printing temperature, then it is clear that the extrudate achieves an optimal condition for better shape stability between a lower boundary that is below 105 \({}^{\circ}\)C and a higher boundary at 110 \({}^{\circ}\)C.
* The mechanical analysis on 3D printed samples shows that UTS and Young's modulus are significantly lower compared to ABS and PLA plastics. However, the mechanical properties of Wax3D are superior in comparison to some commercially available IC waxes. Nevertheless, to manufacture thin-walled objects, the stiffness of the Wax3D material should be improved. As for the rheological characterization employing a rotational rheometer, the results show that the Wax3D melt has low complex viscosity and viscoelastic moduli at printing temperature compared to popular FDM polymer melts. On the one hand, the low viscosity of the material is beneficial when it comes to dewaxing the pattern during the RIC process. On the other hand, it greatly increases surface roughness. Nevertheless, it was found that by applying the chemical treatment on the surface of the printed part, the surface quality can be improved to reach the value of Ra = 3.2 \(\upmu\)m. As for the chemical agent, white spirit has proved to be an effective material. Future work might include an investigation aiming to address the quality of castings made with the help of 3D printed wax patterns and the selection of proper dewaxing procedures. In sum, the current work has shown that by running a Taguchi analysis and material characterization, it was possible to identify that the quality of 3D printed wax parts are mainly influenced by printing temperature. The results of the study can be helpful for those who are interested in using the Wax3D filament for the fabrication of IC patterns or other applications. This study is a part of an ongoing research project which will also evaluate the quality of castings produced using Wax3D patterns. Conceptualization, M.M. and M.H.A. ; methodology, M.M. ; formal analysis, M.M., M.H.A. and E.S. ; investigation, M.M. ; resources, M.H.A. and E.S. ; data curation, M.M. ; writing--original draft preparation, M.M. ; writing--review and editing, M.H.A. and E.S. ; supervision, M.H.A. and E.S. ; funding acquisition, M.H.A. All authors have read and agreed to the published version of the manuscript.