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.
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