2025 Volume 64 Issue 4 Pages 324-335
The mechanical properties of models are crucial in determining the industrial applications of additive manufacturing (AM) techniques. Material jetting (MJT) has been primarily limited to mold-making, prototyping, etc., owing to its low strength. Ricoh Co., Ltd. has succeeded in developing a 3D Printer capable of strong full-color resin composite. To improve the strength, we optimized the filler shape, modified the surface properties, and optimized the monomer formulation of the ink. To develop a colorization process suitable for filler-added inks, we investigated a method to apply transparent ink over small-colored ink droplets. We achieved a bending strength of 180 MPa for colorless models and 177 MPa for colored models, which is remarkable compared to the typical MJT and VPP (Vat Photopolymerization) product strength of 80 MPa or less. This technology makes the direct manufacturing of production parts requiring both esthetic beauty and high strength in colors, such as artificial teeth, dentures, and eyeglass frames, more realistic.
