Influence of Build Orientation on Mechanical Properties and Machinability of H13 Tool Steel Endmills Produced via Material Extrusion Additive Manufacturing

The study aimed to determine the effect of build orientation on surface roughness, microstructure, density, and mechanical behavior including tensile strength and hardness of H13 tool steel produced through process of Filament-based Material Extrusion (FME) Additive Manufacturing (AM). The machinability of AM Endmills produced from these materials was also studied. FME as a new method to fabricate tools based on complex geometries and custom designs. The results showed that the specimen with 45 o orientation had roughest surface were 11.1 μm and 13.4 μm, while 0 o orientation had a smoother surface were 4.5 μm and 3.4 μm. The specimen of 0 o orientation had a greater tensile strength of 1321 MPa which was better than 733 MPa and 772 MPa for 45 o and 90 o respectively. Orientation also affected hardness, was confirmed from 584 HV recorded at 0 o orientation compared to 233 HV and 476 HV for 45 o and 90 o orientations respectively. Microstructure analysis showed dimple in fracture surface was different based on orientations. The dimples in 0 o orientation tended to be evenly distributed, leading to greater tensile strength compared to the others. The density of H13 tool steel ranges from 7.186 – 7.238 g/cm 3 , there had 6.81 – 7.48% porosity compared with conventional. The machinability of AM Endmill was close to conventional endmills with a surface quality of grade N8 and have been improved by polished to surface quality of grade N6. The study showed the potential application of this method to developed special tools in the manufacturing industry.