Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
권호 표지
DOI QR코드

DOI QR Code

The Improvement of Weldline and Flow mark Defection by using Injection Molding Analysis

사출성형 해석을 통한 Weldline 및 Flow mark 개선사례

  • Received : 2013.10.01
  • Accepted : 2013.11.20
  • Published : 2013.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

The cause of flow mark defect is known as non-uniform temperature of mold surface when the flow front meets the cold cavity. The exact definition and classification of Flow mark is not clear because the mechanism of flow mark is not figured out till now. Any injection molding analysis software can not predict the flow mark phenomena. To solve weldline and flow mark defects, the gate thickness is reduced to increase the melt front velocity and the melt front velocity of the flow mark area is increased from 82.3mm/s to 104.7mm/s. In addition, the bulk temperature of the flow mark area is increased from $178.3^{\circ}C$to $215.2^{\circ}C$ by adding a cold slug well. The flow mark phenomena can be greatly reduced by increasing the flow front velocity and elevating the bulk temperature.

Keywords

References

  1. Bulters, M. and Schepens, A., "The Origin of the Surface Defect 'Slip-Stick' on Injection Molded Products," Proc. of the 16th Annual Meeting of the Polymer Processing Society, pp. 144-145, 2000.
  2. Chang, M. C. O., "On the Study of Surface Defects in the Injection Molding of Rubber-modified Thermoplastics," ANTEC '94, pp. 360-367, 1994.
  3. Hobbs, S. Y., "The Development of Flow Instabilities during the Injection Molding of Multi-component Resins," Polym. Eng. Sci., Vol. 36, No. 11, pp. 1489- 1494, 1996. https://doi.org/10.1002/pen.10543
  4. Hamada, H. and Tsunasawa, H., "Correlation between flow mark and internal structure of thin PC/ABS blend injection moldings," Journal of Applied Polymer Science, Vol. 60, No. 3, pp. 353-362, 1996. https://doi.org/10.1002/(SICI)1097-4628(19960418)60:3<353::AID-APP8>3.0.CO;2-K
  5. Monasse, B., Vincent, M., Haudin, J. M., Gazonnet, J. P., Durand. V., and et al., "Flow marks in Injection Molding of Polypropylene : Influence of Processing Conditions and Formation in Fountain Flow," Proc, of the 15th Annual Meeting of the Polymer Processing Society, s'Hertogenbosch, 1999.
  6. Grillet, A. M., Bogaerds, A. C. B., Peters, G. W. M., Baaijens, F. P. T., and Bulters, M., "Numerical analysis of flow mark surface defects in injection molding flow," Journal of Rheology (1978-present), Vol. 46, No. 3, pp. 651-669, 2002. https://doi.org/10.1122/1.1459419
  7. SIMPOE SAS, "SIMPOE Theoretical Manual," 2012.
  8. Alves, M. A., Pinho, F. T., and Oliveira, P. J., "Study of steady pipe and channel flows of a single-mode Phan-Thien-Tanner fluid," Journal of Non- Newtonian Fluid Mechanics, Vol. 101, No. 1-3, pp. 55-76, 2001. https://doi.org/10.1016/S0377-0257(01)00159-8
  9. Grillet, A. M., Bogaerds, A. C. B., Peters, G. W. M., and Baaijens, F. P. T., "Stability Analysis of Constitutive Equations for Polymer Melts in Viscometric Flows," Journal of Non-Newtonian Fluid Mechanics, Vol. 103, No. 2-3, pp. 221-250, 2002. https://doi.org/10.1016/S0377-0257(02)00005-8
  10. Kamal, M. R., Chu, E., Lafleur, P. G., and Ryan, M. E., "Computer Simulation of Injection Mold Filling for Viscoelastic Melts with Fountain Flow," Polymer Engineering & Science, Vol. 26, No. 3, pp. 190-196, 1986. https://doi.org/10.1002/pen.760260303
  11. King, R. C., Apelian, M. R., Armstrong, R. C., and Brown, R. A., "Numerically Stable Finite Element Techniques for Viscoelastic Flow Calculations in Smooth and Singular Geometries," J. NonNewtonian Fluid Mech. Vol. 29, pp. 147-216, 1989.
  12. Sato, T., and Richardson, S. M., "Numerical simulation of the fountain flow problem for viscoelastic fluids," Polymer Engineering & Science, Vol. 35, No. 10, pp. 805-812, 1995. https://doi.org/10.1002/pen.760351003
  13. Park, K., Sohn, D. -H., and Seo, Y. S., "Investigation of Weldline Strength with Various Heating Conditions," J. Korean Soc. Precis. Eng., Vol. 27, No. 1, pp. 105-112, 2010.
  14. Kwon, O. K., Yun, J. H., and Park, K., "Improvement of Moldability for Ultra Thin-Wall Molding with Micro-Patterns," Trans. Korean Soc. Mech. Eng. A., Vol. 31, No. 5, pp. 556-561, 2007. https://doi.org/10.3795/KSME-A.2007.31.5.556

Cited by

  1. The Application of 3D Injection Molding Simulation in Gate Location Selection for Automotive Console vol.18, pp.3, 2014, https://doi.org/10.9726/kspse.2014.18.3.051
  2. Development of Injection Mold for Subminiature Lenses Using Shell Runners Containing Multiple Holes vol.32, pp.11, 2015, https://doi.org/10.7736/KSPE.2015.32.11.961