This study aims to optimize the process conditions for high-density polyethylene (HDPE) additive manufacturing through asystematic analysis of key variables, including material selection, layer height, feed rate, melting temperature, and bedtemperature. By exercising precise control over these variables, optimal conditions were established, which included amelting temperature of 240oC, a welding speed of 150 cm/min, and a material throughput of 5.66 kg/h. Furthermore, theprocess was refined by implementing a zig-zag layering method, which significantly improved the stability, bonding strength,and overall mechanical properties of the final HDPE products. The effects of these optimized process conditions wereassessed through a series of mechanical tests, such as tensile tests, impact tests, and heat deflection temperature (HDT)tests. As a result, the defined process conditions yielded excellent mechanical performance, achieving a tensile strength of21.15 MPa, an impact strength of 320 J/m, and an HDT of 93oC. Overall, this study illustrates the enhancement of HDPEadditive manufacturing quality through the optimization of process conditions. The strategic implementation of theseoptimized variables, along with advanced extrusion module design, demonstrates the potential for producing high-qualityand cost-effective HDPE products, thereby underscoring their enhanced marketability and performance potential.