Shape Contraction in Sintering of 3D Objects Fabricated via Metal Material Extrusion in Additive Manufacturing
Koki Jimbo* and Toshitake Tateno**,
*Graduate School of Science and Technology, Meiji University
1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
**Department of Mechanical Engineering Informatics, Meiji University, Kawasaki, Japan
Additive manufacturing (AM) using metal materials (metal AM) is useful in the fabrication of metal parts with complex shapes, which are difficult to manufacture via subtractive processing. Metal AM is employed in the manufacture of final products as well as in prototyping. Recently, certain metal-AM machines have been commercialized. Powder-bed fusion and direct energy deposition are the main types of metal AM; they require the use of a high-power laser or electron beam and most of them are highly expensive. On the other hand, AM machines of the material-extrusion (ME) type can fabricate metal parts at a low cost. ME is the method of extruding materials from a nozzle and fabricating thin layers. By mixing a metal filler with a base material, it is possible to impart various mechanical properties to the extruded material, such as electrical or thermal conductivity. If the extruded material is baked in a furnace after fabrication, the object can be sintered. During the sintering process, the fabricated objects always shrink and dimensional errors occur. One of the reasons for the shrinkage is that voids are generated inside the object after the degreasing process and collapse during the sintering process. Because the void is generated as a space by replacing a binder that becomes vaporized during the degreasing process, the shrinkage may be controlled by decreasing the content in polymers. In this study, the effect of the metal filler density on the shrinkage in shape was investigated through experiments using two types of metal ME AM. One type is the fused filament fabrication (FFF), in which a material that consists of a metal filler and fused plastics is extruded; the other type is the ultrasonic vibration-assisted ME (UVAME) device, in which a metal powder suspension with a small amount of thickening polymer is extruded. In the latter method, materials with an extremely high density in metal fillers were used; it was considered that degreasing was not required. Two types of specimens were fabricated using AM devices; they were then degreased and sintered. The resulting shapes of the objects were measured with a 3D scanner and were compared. The experimental results showed that the shrinkage of the material with a high density of metal fillers was less than that of the material with a low density of metal fillers.
-  M. Tomlin and J. Meyer, “Topology Optimization of an Additive Layer Manufactured (ALM) Aerospace Part,” Altair CAE Technology Conf., 2011.
-  P. Bartolo, J. P. Kruth, J. Silva, G. Levy, A. Malshe, K. Rajurkar, M. Mitsuishi, J. Ciurana, and M. Leu, “Biomedical production of implants by additive electro-chemical and physical processes,” CIRP Annals – Manufacturing Technology, Vol.61, pp. 635-655, 2012.
-  K. Hiroshi, T. Kohei, and N. Hiroyuki, “Low-Energy Injection Molding Process by a Mold with Permeability Fabricated by Additive Manufacturing,” Int. J. of Automation Technol., Vol.10, pp. 101-105, 2016.
-  K. Hiroshi, F. Hironobu, and N. Hiroyuki, “Improvement in the Permeability Characteristics of Injection Mold Fabricated by Additive Manufacturing and Irradiated by Electron Beams,” Int. J. of Automation Technol., Vol.11, pp. 97-103, 2017.
-  M. Schmidt, M. Merklein, D. Bourell, D. Dimitrov, T. Hausottef, K. Wegener, L. Overmeyer, F. Vollertsen, and G. N. Levy, “Laser based additive manufacturing in industry and academia,” CIRP Annals – Manufacturing Technology, Vol.66, pp. 561-583, 2017.
-  K. Ryo, M. Taro, K. Yasuhiro, and O. Yohei, “Basic Study on Remelting Process to Enhance Density of Inconel 625 in Direct Energy Deposition,” Int. J. of Automation Technol., Vol.12, pp. 424-433, 2018.
-  S. Naoki and S. Hiroshi, “Deposition Conditions for Laser Formation Processes with Filler Wire,” Int. J. of Automation Technol., Vol.10, pp. 899-908, 2016.
-  H. Alsalla, L. Hao, and C. Smith, “Fracture toughness and tensile strength of 316L stainless steel cellular lattice structures manufactured using the selective laser melting technique,” Materials Science and Engineering A, Vol.669, pp. 1-6, 2016.
-  R. Mahshida, H. N. Hansena, and K. L. Højbjerre, “Strength analysis and modeling of cellular lattice structures manufactured using selective laser melting for tooling applications,” Materials and Design, Vol.104, pp. 276-283, 2016.
-  Y. Li, H. Jahr, K. Lietaert, P. Pavanram, A. Yilmaz, L. I. Fockaert, M. A. Leeflang, B. Pouran, Y. Gonzalez-Garcia, H. Weinans, J. M. C. Mol, J. Zhou, and A. A. Zadpoor, “Additively manufactured biodegradable porous iron,” Acta Biomaterialia, Vol.77, pp. 380-393, 2018.
-  R. Hedayati, S. Amin Yavari, and A. A. Zadpoor, “Fatigue crack propagation in additively manufactured porous biomaterials,” Materials Science and Engineering C, Vol.76, pp. 457-463, 2017.
-  B. G. Compton and J. A. Lewis, “3D-Printing of Lightweight Cellular Composites,” Advanced Materials, Vol.26, pp. 5930-5935, 2014.
-  S. Hwang, E. I. Reyes, K. Moon, R. C. Rumph, and N. S. Kim, “Thermo-mechanical Characterization of Metal/Polymer Composite Filaments and Printing Parameter Study for Fused Deposition Modeling in the 3D Printing Process,” J. of Electronic Materials, Vol.44, No.3, pp. 771-777, 2015.
-  T. Hayashi, Y. Takaya, and D. Lee, “LCD Microstereolithography of Photosensitive Resin with Functional Particles,” Int. J. of Automation Technol., Vol.2, No.3, pp. 182-189, 2008.
-  M. Alhijjaj, P. Belton, and S. Qi, “An investigation into the use of polymer blends to improve the printability of and regulate drug release from pharmaceutical solid dispersions prepared via fused deposition modeling (FDM) 3D printing,” European J. of Pharmaceutics and Biopharmaceutics, Vol.108, pp. 111-125, 2016.
-  H. Wu, M. Sulkis, J. Driver, A. Saade-Castillo, A. Thompson, and J. H. Koo, “Multi-functional ULTEM™ 1010 composite filaments for additive manufacturing using Fused Filament Fabrication (FFF),” Additive Manufacturing, Vol.24, pp. 298-306, 2018.
-  P. Nandwana, A. M. Elliott, D. Siddel, A. Merriman, W. H. Peter, and S. S. Babu, “Powder bed binder jet 3D printing of Inconel 718: Densification, microstructural evolution and challenges,” Current Opinion in Solid State and Materials Science, Vol.21, pp. 207-218, 2017.
-  J. A. Gonzalez, J. Mireles, Y. Lin, and R. B. Wicker, “Characterization of ceramic components fabricated using binder jetting additive manufacturing technology,” Ceramics Int., Vol.42, pp. 10559-10564, 2016.
-  T. Tateno, A. Kakuta, H. Ogo, and T. Kimoto, “Ultrasonic Vibration-Assisted Extrusion of Metal Powder Suspension for Additive Manufacturing,” Int. J. of Automation Technol., Vol.12, No.5, pp. 775-783, 2018.
-  D. F. Heaney, T. W. Mueller, and P. A. Davies, “Mechanical properties of metal injection moulded 316L stainless steel using both prealloy and master alloy techniques,” Powder Metallurgy, Vol.47, pp. 367-373, 2004.