Experimental study of wax-material support structure for fused deposition modeling printed parts with overhanging sections

Additive manufacturing of PLA parts using wax-based filament as a support structure was investigated by implementing the 2-level 3-factors full factorial design of experiments (DoE). The aim of the experiments was to identify significant FDM factors that affect the surface roughness of the parent part in the PLA/Wax interfacial region. In addition, the important factors influencing bonding strength between PLA and wax were identified using the same full factorial DoE. The printing parameters chosen for the analysis are printing temperature, nozzle speed, and the pattern type at the interfacial area. The findings of the study show that the wax-based filament can be effectively used as support material with the condition that the PLA printing temperature is at its lowest value and the nozzle speed is close to 40 mm/s. With the optimal printing condition, the surface roughness value (Ra) can reach as low as 18 μm value and the bonding strength of 0.27 MPa at the interfacial area. The results of the study have revealed the capability of FDM technology to join materials having considerably dissimilar properties.