Abstract
A crucial problem in injection molding of the thick plastic stem that is a key part of high-pressure gas valve is the formation of internal voids, because the structural failure of plastic stem owing to the internal voids not only deteriorates the operating function of gas valve but also may lead to the tremendous loss of financial and human resources. In this context, the goal of this study is to examine whether the formation of internal voids can be successfully suppressed when injection molding is replaced with injection compression molding. To examine this possibility, the major mold flow characteristics between injection molding and injection compression molding are firstly compared through 3-D thermal flow analyses. Next, for the sake of verification of numerical comparison, the plastic stem specimens are manufactured by both molding processes and the internal void formation is inspected using X-ray photos and cutting planes of specimens. Through the comparative numerical and experimental studies, it is confirmed that the crucial formation of internal voids in the conventional injection molding process can be successfully and completely removed by employing the injection compression molding.
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References
Yao D, Kim B (2002) Injection molding high aspect ratio microfeatures. J Injection Molding Technol 6:11–17
Xu G, Yu L, Lee J, Koelling KW (2005) Experimental and numerical studies of injection molding with microfeatures. Polym Eng Sci 45(6):866–875
Sha B, Cimov S, Griffiths C, Packianather MS (2007) Investigation of micro-injection moulding: factors affecting the replication quality. J Mater Process Technol 183(2–3):284–296
Yoshii M, Kuramoto H, Ochiai Y (1998) Experimental study of the transcription of minute width grooves by injection molding (II). Polym Eng Sci 38(9):1587–1593
Yao D, Chen SC, Kim BH (2009) Rapid thermal cycling of injection molds: an overview on technical approaches and applications. Adv Polym Technol 27(4):233–255
Yokoi H, Han X, Takahashi T, Kim WK (2006) Effects of molding conditions on transcription molding of microscale prism patterns using ultra-high-speed injection molding. Polym Eng Sci 46(9):1140–1146
Greener J (1986) General consequences of the packing phase in injection molding. Polym Eng Sci 26(12):886–892
Yang SY, Ke MZ (1995) Experimental study on the effects of adding compression to injection molding process. Adv Polym Technol 14(1):15–24
Chen CM, Young WB (2000) The effects of compression pressure on injection compression molding. Int Polym Process 15(2):176–179
Chen SC, Chen YC, Cheng NT, Huang MS (1998) Simulation of injection-compression mold-filling process. Int Commun Heat Mass Transfer 25(7):907–917
Haberstroh E, Berthold J, Jüntgen T (2000) Injection-compression molding of glass-fiber filled phenolic molding compounds. Adv Eng Mater 2(11):752–756
Michaeli W, Hebner S, Klaiber F, Jorster J (2007) Geometrical accuracy and optical performance of injection moulded and injection-compression moulded plastic parts. Ann CIRP 56(1):545–548
Guan WS, Huang HX (2012) Back melt flow injection-compression molding: effect on part thickness distribution. Int Commun Heat Mass Transfer 39:792–797
CH W, Chen WS (2006) Injection molding and injection compression molding of tree-beam grating of DVD pickup lens. Sensors Actuators 125:367–375
Kwon OG, Han MS (2004) Failure analysis of the exhaust valve stem from a Waukesha P9390 GSI gas engine. Eng Fail Anal 11(3):439–447
MoldFlow Corporation (2012) MoldFlow plastics insight 4.1. Moldflow Corporation, Wayland
Wu CH, Su WY (2003) Optimization of wedge-shaped parts for injection molding and injection compression molding. Int Commun Heat Mass Transfer 30(2):215–224
Huang MS, Chung CF (2010) Injection molding and injection compression molding of thin-walled light-guided plates with V-grooved macrofeatures. J Appl Polym Sci 121(2):1151–1159
Cho JR, Ha DY (2001) Averaging and finite-element discretization approaches in the numerical analysis of functionally graded materials. Mater Sci Eng A 302(2):187–196
Cho JR, Lee HW, Sohn JS, Woo JS (2006) Numerical investigation of hydroplaning characteristics of three-dimensional patterned tire. Eur J Mech A/Solids 25:914–926
Verhoyen O, Dupret F (1998) A simplified method for introducing the cross viscosity law in the numerical simulation of Hele haw flow. J Non-Newtonian Fluid Mech 74(1–3):25–46
Cho JR, Choi JH (2016) Numerical investigation of weather strip extrusion forming process by thermal flow analysis. Int J Adv Manufac Technol. doi:10.1007/s00170-016-8670-9
Cho JR, Lee SY (2003) Dynamic analysis of baffled fuel-storage tanks using the ALE finite element method. Int J Numer Methods Fluids 41:185–208
Höhne GWH, Hemminger WF, Flammersheim HJ (2013) Differential scanning calorimetry. Springer-Verlag, New York
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Han, S.R., Cho, J.R., Beak, S.K. et al. Numerical and experimental studies of injection compression molding process for thick plastic gas valve stem. Int J Adv Manuf Technol 89, 651–660 (2017). https://doi.org/10.1007/s00170-016-9139-6
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DOI: https://doi.org/10.1007/s00170-016-9139-6