Abstract
We applied an insulating polymer layer to the surface of mold cavity to injection-mold large plastic parts with a microsized thickness. Polyimide (PI) was coated on the mold wall using spray coating method. A thin light guide plate (LGP) was designed and fabricated via micro-injection molding. The polymeric coating layer could enhance the fluidity of polymer melt in the cavity during filling stage by minimizing the formation of the skin layer during injection molding. The surface roughness and pattern transfer rate of the LGPs were analyzed experimentally. In addition, numerical simulation was carried out to understand the insulation effect of the layer in the injection molding.
Similar content being viewed by others
References
Annicchiarico D, Attia UM, Alcock JR (2013) Part mass and shrinkage in micro injection moulding: statistical based optimisation using multiple quality criteria. Polym Test 32(6):1079–1087
Azaman MD, Sapuan SM, Sulaiman S, Zainudin ES, Khalina A (2013) Shrinkages and warpage in the processability of wood-filled polypropylene composite thin-walled parts formed by injection molding. Mater Des 1980–2015(52):1018–1026
Guan W-S, Huang H-X (2012) Back melt flow in injection–compression molding: effect on part thickness distribution. Int Commun Heat Mass Transf 39(6):792–797
Huang M-C, Tai C-C (2001) The effective factors in the warpage problem of an injection-molded part with a thin shell feature. J Mater Process Technol 110(1):1–9
Jeng M-C, Chen S-C, Minh PS, Chang J-A, C-s Chung (2010) Rapid mold temperature control in injection molding by using steam heating. Int Commun Heat Mass Transf 37(9):1295–1304
Kim YC (2014) LGP pattern design with single LED light source. Optik Int J Light Electron Opt 125(3):1341–1345
Lee J-H, Lee H-S, Lee B-K, Choi W-S, Choi H-Y, Yoon J-B (2007) Simple liquid crystal display backlight unit comprising only a single-sheet micropatterned polydimethylsiloxane (PDMS) light-guide plate. Opt Lett 32(18):2665–2667
Li C-J, Fang Y-C, Cheng M-C (2009) Study of optimization of an LCD light guide plate with neural network and genetic algorithm. Opt Express 17(12):10177–10188
Li C-J, Fang Y-C, Cheng M-C (2010) Prism-pattern design of an LCD light guide plate using a neural-network optical model. Optik Int J Light Electron Opt 121(24):2245–2249
Liou A-C, Chen R-H (2006) Injection molding of polymer micro- and sub-micron structures with high-aspect ratios. Int J Adv Manuf Technol 28(11):1097–1103
Ogorodnyk O, Martinsen K (2018) Monitoring and control for thermoplastics injection molding a review. Procedia CIRP 67:380–385
Oh HJ, Song YS (2015) Precise nanoinjection molding through local film heating system. RSC Advances 5(121):99797–99805
Oh HJ, Song YS (2017) Surface strengthening of injection molded parts by applying a thermal insulation film. Rsc Adv 7(23):14302–14308
Oliaei E, Heidari BS, Davachi SM, Bahrami M, Davoodi S, Hejazi I, Seyfi J (2016) Warpage and shrinkage optimization of injection-molded plastic spoon parts for biodegradable polymers using Taguchi, anova and artificial neural network methods. J Mater Sci Technol 32(8):710–720
Othman MH, Hasan S, Khamis SZ, Ibrahim MHI, Amin SYM (2017) Optimisation of injection moulding parameter towards shrinkage and warpage for polypropylene-nanoclay-gigantochloa scortechinii nanocomposites. Procedia Engineering 184:673–680
Park S, Shin Y, Choi E, Ma H, Lee S (2012) Improvement of luminance and uniformity of light guide panel using scatterer pattern by laser processing. Opt Laser Technol 44(5):1301–1306
Patrice M, Julien G (2018) Micro-injection molding of thermoplastic polymers: proposal of a constitutive law as function of the aspect ratios. J Appl Polym Sci 135(4):45719
Piotter V, Mueller K, Plewa K, Ruprecht R, Hausselt J (2002) Performance and simulation of thermoplastic micro injection molding. Microsyst Technol 8(6):387–390
Sortino M, Totis G, Kuljanic E (2014) Comparison of injection molding technologies for the production of micro-optical devices. Procedia Engineering 69:1296–1305
Teng T-C, Kuo M-F (2010) Highly precise optical model for simulating light guide plate using LED light source. Opt Express 18(21):22208–22214
Yu M-C, Young W-B, Hsu P-M (2007) Micro-injection molding with the infrared assisted mold heating system. Mater Sci Eng A 460–461:288–295
Acknowledgements
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1D1A1B07049173) and by the Korea government (MSIT) (No. NRF-2018R1A5A1024127). The authors are grateful for the supports.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Kim, D.H., Song, Y.S. Micro-injection molding using a polymer coated mold. Microsyst Technol 25, 4011–4017 (2019). https://doi.org/10.1007/s00542-019-04320-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00542-019-04320-7