抄録
The fuse deposition modeling (FDM) type 3D printer is getting popular because its price is decreased within the range of the personal usage level. The main purpose of the present FDM 3D printer is to make an outer shape example to confirm the design. Therefore, the printer driver is tend to develop to reduce the consumption of the filament material. Hence, the output products are generally too weak for the mechanical parts. ABS polymer, one of the material of the FDM 3D printer, has the sufficient mechanical property (strength, toughness) for the light load mechanical parts. May be we can make mechanical parts by 3D printer if we design the driver for it. For that purpose, the optimization of the inner structure of the 3D printer output products will be getting very important. In the case of the 3D printer, the flexibility to design the internal structure is much larger than any of the conventional manufacturing method. So in this study, we investigated how to make an inner structure of the 3D printer. We first compare the structure of the honeycomb, tetrahedron and lattice. During the research, we found that to manufacture a solid structure is very difficult for our 3D printer (Up! Plus). Therefore, we previously investigated how to manufacture a solid structure by using our 3D printer and driver. The answer was to slice the solid body to the thin layers in the 3D-CAD model. By using this technic, we produced a rectangular test pieces with our designed internal structure, and made bending and torsion tests to get the bending/torsional specific rigidity. The results are compared to the FEM analyses. The results showed that the honeycomb structure is stronger than the tetrahedron or the lattice. The directions of the honeycomb walls were compared and found that the cross sectional horizontal direction is the best for the bending and the torsional specific rigidity. An introduction of the fillets between outer plates and honeycomb end is very effective for the bending specific rigidity. The variation of the thickness of the honeycomb wall was also investigated.
