Improvement in the Permeability Characteristics of Injection Mold Fabricated by Additive Manufacturing and Irradiated by Electron Beams
Hiroshi Koresawa†, Hironobu Fujimaru, and Hiroyuki Narahara
Department of Mechanical Information Science and Technology, Kyushu Institute of Technology
680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan
This paper describes a metal mold with permeability fabricated by metal laser sintering with high-speed milling, which is an additive manufacturing method, and discusses the improvement in permeability. In this method, the sintered body is produced with gas exhaust tubes based on the porous structure. To maintain permeability, ensuring that the gas exhaust tube is not blocked is essential. Blockages may occur because of reasons such as the deformation of the gas exhaust tube due to the milling process during fabrication and generation of mold deposits within the gas exhaust tube during injection molding. In this research, by irradiating the surface of a sintered body, with a gas exhaust tube, by an electron beam, water repellency attributed to the reduction in surface free energy and recovery of permeability are confirmed. Further, in a fundamental experiment with an injection molding machine, the permeability of a permeable sintered body irradiated an electron beam increased by approximately 2.8 times as compared to the permeability of a sintered body that was not irradiated.
-  S. Abe, Y. Higashi, I. Fuwa, N. Yoshida, and T. Yoneyama, “Milling-Combined Laser Metal Sintering System and Production of Injection Molds with Sophisticated Functions,” Towards Synthesis of Micro-/Nano-systems: The 11th International Conference on Precision Engineering (ICPE) August 16–18, 2006, Tokyo, Japan, pp. 285-290, 2007.
-  T. Yoneyama, H. Kagawa, Y. Yamade, T. Ito, M. Inagi, Y. Takino, and C. Yan, “Effective Cooling and Accuracy Improvement in Injection Molding Using a Metal Mold with Cooling Channels Composed by Laser Sintering (3rd Report) – Cooling by the Steel Powder Mold with Cooling Channels –,” Journal of the Japan Society for Precision Engineering, Vol.71, pp. 347-351, 2005 (in Japanese).
-  T. Yoneyama, H. Kagawa, Y. Suehiro, S. Abe, and M. Miyamaru, “Reduction in Injection Cycle Time Using a Milling-Combined Laser Metarl Sintered Mold,” Journal of the Japan Society of Polymer Processing, Vol.19, pp. 662-668, 2007 (in Japanese).
-  T. Yoneyama and H. Kagawa, “Fabrication of Cooling Channels in the Injection Molding by Laser Metal Sintering,” International Journal of Automation Technology, Vol.2, pp. 162-167, 2008.
-  T. Yoneyama, K. Naito, S. Abe, and M. Miyamaru, “Reduction of Injection Pressure for Thin Walled Molding using the Laser Metal Sintered Mold,” Journal of the Japan Society for Precision Engineering, Vol.76, pp. 188-192, 2010 (in Japanese).
-  T. Yoneyama, S. Abe, and M. Miyamaru, “Reducing Weld Line by Heating Mold Surface with Heater Embedded by Laser Metal Sintering,” International Journal of Automation Technology, Vol.6, pp. 591-596, 2012.
-  K. Hiroshi, T. Kohei, and N. Hiroyuki, “Low-Energy Injection Molding Process by a Mold with Permeability Fabricated by Additive Manufacturing,” International Journal of Automation Technology, Vol.10, pp. 101-105, 2016.
-  M. Kojima, H. Narahara, Y. Nakao, H. Fukumaru, H. Koresawa, H. Suzuki, and S. Abe, “Permeability Characteristics and Applications of Plastic Injection Molding Fabricated by Metal Laser Sintering Combined with High Speed Milling,” International Journal of Automation Technology, Vol.2, pp. 175-181, 2008.
-  H. Narahara, S. Takeshita, H. Fukumaru, H. Koresawa and H. Suzuki, “Permeability Performance on Porous Structure of Injection Mold Fabricated by Metal Laser Sintering Combined with High Speed Milling,” International Journal of Automation Technology, Vol.6, pp. 576-583, 2012.
-  H. Koresawa, S. Kawano, H. Narahara, and H. Suzuki, “Characteristics of Air Permeability for Injection Mold Fabricated by the Metal Laser Sintering with High Speed Milling,” Journal of the Japan Society for Precision Engineering, Vol.80, pp. 1018-1022, 2014 (in Japanese).
-  D. I. Proskurovsky, V. P. Rotshtein, and G. E. Ozur, “Use of low-energy, high-current electron beams for surface treatment of materials,” Surface and Coatings Technology, Vol.96, pp. 117-122, 1997.
-  Y. Uno, A. Okada, K. Uemura and R. Purwadi, US Patent 7049539.
-  A. Okada, Y. Okamoto, Y. Uno, and K. Uemura, “Improvement of surface characteristics for long life of metal molds by large-area EB irradiation,” Journal of Materials Processing Technology, Vol.214, pp. 1740-1748, 2014.
-  A. Okada, Y. Uno, N. Yabushita, K. Uemura, and P. Raharjo, “High Efficiency Surface Finishing of Metal Mold by Large-are Electron Beam Irradiation (1st Report) – Possibility of Smoothing of EDMed Surface and Analysis of Fundamental Machining Characteristics –,” Journal of the Japan Society for Precision Engineering, Vol.69, pp. 1464-1468, 2003 (in Japanese).
-  A. Okada, Y. Uno, K. Nishina, K. Uemura, P. Raharjo, S. Sano, and Y. Zhanbo, “High Efficiency Surface Finishing of Metal Mold by Large-are Electron Beam Irradiation (2nd Report) – Smoothing of Tilting Surfaces and Surface Modification Effect –,” Journal of the Japan Society for Precision Engineering, Vol.71, p.5, 2005 (in Japanese).
-  A. Okada, Y. Daichi, A. Kondoh, Y. Uno, S. Sano and K. Uemura, “High Efficiency Surface Finishing of Metal Mold by Large-are Electron Beam Irradiation (3rd Report) – Relationship Between Crater Generation and Workpece Material –,” Journal of the Japan Society for Precision Engineering, Vol.74, pp. 385-389, 2008 (in Japanese).
-  Y. Kitazaki and T. Hata, “Surface-Chemical Criteria for Optimum Adhesion,” The Journal of Adhesion, Vol.4, pp. 123-132, 1972.
-  Y. Kitazaki and T. Hata, “Extension of Fowkes’ Equation and Estimation of Surface Tension of Polymer Solids,” Journal of the Adhesion Society of Japan, Vol.8, pp. 131-142, 1972 (in Japanese).
-  T. Hata, Y. Kitazaki, and T. Saito, “Estimation of the Surface Energy of Polymer Solids,” The Journal of Adhesion, Vol.21, pp. 177-194, 1987.
-  K. Shimoyama, S. Nosho, and H. Nakamori, Japanese Patent JP2005-337781A.
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