Multi-material structures formed by combining different materials to achieve superior properties have always attracted considerable interest. In industry, multi-material structures are generally produced using conventional joining methods such as mechanical fastening, welding, and adhesive bonding. In recent years, advances in additive manufacturing and 3D printing technologies have made it possible to fabricate multi-material structures without the need for additional parts or components beyond the constituent materials themselves. Despite these advantages, the production of multi-material structures can be challenging due to interfacial bonding behaviors arising from the different chemical structures of dissimilar materials. In this research, Multi-material (MM) parts consisting of an ABS Plus (Acrylonitrile Butadiene Styrene Plus) core and a PLA (Polylactic Acid) outer layer were produced using a 3D printer at different layer thicknesses (0.1, 0.2, and 0.3 mm) and infill ratios (20, 50, 80, and 100%). Tensile and flexural tests were performed on the fabricated specimens, and the fracture surfaces were examined. The results showed that PLA exhibited higher tensile and flexural strengths than ABS Plus. Moreover, the mechanically tested MM specimens demonstrated superior mechanical properties compared to those of the individual constituent materials.