Abstract
Even though injection molding technology has been developed for many years, it is still needed to study the effect of processing conditions on the final properties of injection-molded parts for producing precision products in optical field. The optical anisotropy, i.e., birefringence, is a significant factor which affects the function of many optical components. In the present study, we have focused on the effects of packing and compression processes on the birefringence structure remaining in the disc by examining the gap-wise distribution of birefringence and extinction angle. As a result, two extra birefringence and extinction peaks near the center in thickness direction showed the effect of packing pressure, which came from the extra flow during packing stage. Furthermore, more uniform birefringence distribution was found in injection/compression case than in conventional injection-molded case. Depending on the process condition, even the reversal flow was found from the distribution of extinction angle in injection/compression case. Finally, graphical representation technique of optical refractive indicatrix was suggested to show the difference of final birefringence structure for different process types.
Similar content being viewed by others
References
Baumer, S., 2010, Handbook of plastic optics, Eindhoven, Netherlands, WILEY-VCH.
Chen, S. C., Y. C. Chen, and N. T. Cheng, 1998, Simulation of injection-compression mold-filling process, Int. Comm. Heat Mass Transfer 25, 907–917.
Hecht, E., 1987, Optics, Berlin, Massachusetts, Addison-Wesley.
Isayev, A. I., 1987, Injection and compression molding fundamentals, New York and Basel. Marcel Dekker INC.
Isayev, A. I. and C. A. Hieber, 1980, Toward a viscoelastic modeling of the injection molding of polymers, Rheol. Acta 19, 168–182.
Janeschiz-Kriegl, H., 1983, Polymer melt rheology and flow birefringence, Berlin, Springer Verlag.
Kim, N. H., 2009, Injection-compression and co-injection molding of amorphous polymers; viscoelastic simulation and experiment, Dissertation, U. of Akron.
Lee, H. S. and A. I. Isayev, 2007, Numerical simulation of flow-induced birefringence: comparison of injection and injection/compression molding, Inter. J. of Precision. Eng. And Manuf. 8, 66–72.
Lee, Y. B., T. H. Kwon, and K. H. Yoon, 2002a, Numerical prediction of residual stresses and birefringence in injection/compression molded center-gated disk. part I: basic modeling and results for injection molding, Polym. Eng. Sci 42, 2246–2272.
Lee, Y. B., T. H. Kwon, and K. H. Yoon, 2002b, Numerical prediction of residual stresses and birefringence in injection/compression molded center-gated disk. part II: effects of processing conditions, Polym. Eng. Sci 42, 2273–2292.
Lin, T. H., 2009, Birefringence, anisotropic shrinkage and luminance in injection molded light-guide plate; modeling and experiment, Dissertation, U. of Akron.
Min, I. K., J. S. Kim, Y. B. Ko, H. P. Park, K. H. Yoon, and C. J. Hwang, 2006, An experimental study on the improvement of pattern replication and birefringence in LGP by adding compression effects, Trans. of Maters. Process 15, 27–33.
Shyu, G. D., 1993, Birefringence and residual stresses in molded articles of amorphous polymers, issertation, U. of Akron.
Weng, C., W. B. Lee, S. To, and Bing-yan Jiang, 2009, Numerical simulation of residual stress and birefringence in the precision injection molding of plastic microlens arrays, Int. Comm. Heat Mass Transfer 36, 213–219
Wust, C. J. and D. C. Bogue, 1983, Stress optical behavior in polystyrene; residual stresses and birefringence in large, quenched samples, J. of Appl. Polym Sci. 28, 1931–1947.
Yoon, K., 1995, An experimental study on precision injection molding of center-gated disk. part I: basic modeling and results for injection molding, The Korean J. of Rheol. 7, 19–27.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Min, I., Yoon, K. An experimental study on the effects of injection-molding types for the birefringence distribution in polycarbonate discs. Korea-Aust. Rheol. J. 23, 155–162 (2011). https://doi.org/10.1007/s13367-011-0019-1
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13367-011-0019-1