Influence of Resin Flow State on Aluminum Flake Orientation in a Metallic-Like Resin Product Manufactured Through Injection Molding
Makoto Nikawa*, Takahito Shirota**, and Hiroshi Yamagata*
*Faculty of Engineering, Gifu University
1-1 Yanagido, Gifu 501-11-3, Japan
**Graduate School of Engineering, Gifu University
1-1 Yanagido, Gifu 501-11-3, Japan
A potential method for predicting the orientation of aluminum flakes in a metallic-like product without a coating was examined. To achieve this goal, injection molding test of a thin product was carried out with a metallic-like resin that contained aluminum flakes. Furthermore, the flow state of the base material (polypropylene) of the metallic-like resin during molding was calculated via computer simulations, and the results were compared to the experimental results. The reflectance and orientation of the product were measured as functions of the gate shape and injection speed. The reflectance of the product made with the metallic-like resin was measured with a spectrophotometer, and the orientation of the aluminum flakes was measured via X-ray computed tomography (CT). The reflectance changed according to differences in the gate shape and injection speed. In addition, the orientation of the aluminum flakes changed with the distance from the surface of the product. The shear rate of the base material was calculated immediately after the resin completely filled the mold, and the results correlated well with the orientation of the flakes. The results suggest that it is possible to predict the orientation of aluminum flakes within metallic-like resins.
-  Y. Satoh and T. Kanemaru, “Aluminum paste for metallic paint,” J. Jpn. Soc. Colour Mater., Vol.52, pp. 311-318, 1979.
-  N. Sasaki, “Control of colour fluctuation in base coating with water base metallic paint,” Coating Technology, Vol.50, pp. 109-116, 2011.
-  K. Nakajima, H. Hattori, N. Ito, N. Kita, N. Takada, and M. Sugiyama, “Colour measurement of metallic topcoats,” J. Color Sci. Assoc. Jpn., Vol.16, pp. 69-70, 1992.
-  S. Soga and Y. Shimodaira, “Quality evaluation method for metallic topcoats with imaging technology,” IEICE Technical Report, Vol.110, pp. 13-16, 2010.
-  K. Nobuyuki, T. Sano, S. Kobayashi, and K. Takeuchi, “Field investigations of paint mist and powder at painting booths,” Proc. Jpn. Soc. Atmos. Environ., Vol.50, pp. 588, 2009.
-  J. Tanaka and N. Miyata, “Study on paint wastewater treatment system,” Research on Coatings, pp. 1-7, 2008.
-  T. Michii, Y. Oshima, M. Seto, M. Yamabe, and T. Ishikawa, “Molded-in color in injection molding plates and surface properties,” Seikei-Kakou, Vol.17, pp. 349-355, 2005.
-  H. Nagashima, S. Takahashi, Y. Fukami, and H. Uebayashi, “The VOCs (Volatile Organic Compounds) reduction in a vehicle interior by adopting pre-colored metallic silver plastic parts,” J. Soc. Automotive Engineers, Vol.63, pp. 35-38, 2009.
-  T. Suda, H. Kuroiwa, S. Kabe, Y. Fukushima, M. Oyake, J. Kobayashi, T. Takaoka, and F. Terauchi, “Prediction of orientation of metallic flakes in metallic molded parts by CAE,” Preprints of Seikei-Kakou Autumnal Meeting, pp. 375-376, 2012.
-  T. Suda, H. Kuroiwa, Y. Fukushima, M. Oyake, T. Takaoka, and F. Terauchi, “Identification of mixing ratios of metallic flakes in metallic color products injection-molded by image analysis,” Seikei-Kakou, Vol.27, pp. 109-117, 2015.
-  K. Taira, H. Yokoi, and K. Taki, “Orientation analysis of metallic injection molded sample using X-ray CT technology (Part I),” Preprints of Seikei-Kakou Annual Meeting, pp. 127-128, 2012.
-  K. Taira and H. Yokoi, “Orientation analysis of metallic injection molded sample using X-ray CT technology (Part II),” Preprints of Seikei-Kakou Autumnal Meeting, pp. 333-334, 2012.
-  Y. Kageyama, S. Ogihara, and D. Y. Song, “A study on poor appearance of injection molded plastics,” Proc. JSME M&P Conf. 2010, pp. 533, 2010.
-  G. Wang, G. Zhao, and X. Wang, “Heating/cooling channels design for an automotive interior part and its evaluation in rapid heat cycle molding,” Materials and Design, Vol.59, pp. 310-322, 2014.
-  K. Tsai, C. Hsieh, and W. Lo, “A study of the effects of process parameters for injection molding on surface quality of optical lenses,” J. Mater. Process. Technol., Vol.209, pp. 3469-3477, 2009.
-  P. Postawa and J. Koszkul, “Change in injection moulded parts shrinkage and weight as a function of processing conditions,” J. Mater. Process. Technol., Vol.162-163, pp. 109-115, 2005.
-  G. Wang, G. Zhao, and X. Wang, “Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle molding,” Material and Design, Vol.46, pp. 457-472, 2013.
-  M. Nikawa, Y. Matsui, H. Yamagata, M. Kinoshita, T. Yamawaki, and W. Oikawa, “Injection molding characteristics for weldless molding using aluminum alloy mold coated by iron plating with rapid heating and cooling mold temperature system,” J. Jpn. Soc. Technol. Plasticity, Vol.54, pp. 247-251, 2013.
-  Y. Murata, K. Koike, and S. Pan, “Improving the properties of injection molded products with induction heating and cooling molds,” Int. J. of Automation Technology, Vol.9, pp. 3-9, 2015.
-  T. Yoneyama, S. Abe, and M. Miyamaru, “Reduction of weld-line by the laser metal sintered mold and the effect of hot air preheating,” J. Jpn. Soc. Precision Engineering, Vol.77, pp. 955-959, 2011.
-  H. Yokoi, Y. Murata, K. Oka, and K. Watanabe, “Visual analysis of weld-line generating and vanishing processes using a grass-inserted visual mold,” Seikei-Kakou, Vol.9, pp. 290-298, 1997.
-  M. Nikawa, Y. Matsui, H. Yamagata, and W. Oikawa, “Moldability of injection compression molding of ABS resin with rapid heating and cooling molding using aluminum alloy mold,” The 15th Int. Conf. Precision Engineering, pp. 871-875, 2014.
-  K. Yasuda, N. Ohara, N. Mori, and K. Chiba, “Orientation of disk-like particles in a microcomposite processing,” J. Text. Mach. Soc. Jpn., Vol.58, T29-T36, 2005.
-  Z. Tadmor, “Molecular orientation in injection molding,” J. Appl. Polym. Sci., Vol.18, pp. 1753-1772, 1974.
-  H. Yokoi, Y. Murata, Y. Nishi, and T. Seki, “Visual analysis of fiber orientation process by glass-insert mold,” Seikei-Kakou, Vol.7, pp. 600-607, 1995.