The paper presents experimental research regarding the application of specific low melting metals in the FDM process. Previous trends in the transfer of the filament from the spool to the hot-end showed that the filament undergoes specific mechanical stress during the transfer. To achieve an appropriate transfer the filament should prove stiffness and resistance to the mechanical actions of the transfer wheels. At the same time, the entrance to the hot-end creates specific resistance to the movement of the filament, and the filament undergoes important deformations. The experimental research used three materials characterized by melting temperature below 260oC: Sn-58Bi, Sn-9Zn, and Sn-3.5Ag. Sn-58Bi showed a yield stress above 50 MPa, but very low extension during the tensile test. Sn-9Zn exhibited a yield stress above 30 MPa, and about double the extension during the tensile test. Sn-3.5Ag displayed a yield stress above 25 MPa, and extension in excess of 8%. The analysis of the surface was performed, revealing that the increase of the yield stress influenced the appearance of specific prints given by the transfer wheels. The deepest prints were measured for Sn-3.5Ag and they were maximum 100 μm. The other two materials were stiffer and the prints have depths below 50 μm. According to the obtained results, each of the tested materials can be an appropriate solution to filament use for the FDM 3D printing process.
Experimental Research on 3D Printing Process of Square Hole
