화학공학소재연구정보센터
Korea-Australia Rheology Journal, Vol.16, No.1, 27-33, March, 2004
Modeling of hollow formation and its dynamics in liquid gas assisted injection molding process
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Application of gas assisted injection molding has been expanded during last two decades because of many advantages such as design flexibility, dimensional stability, reduction of machine tonnages, and so on. However, the surface defects including hesitation mark and gloss difference are observed for thick parts. Difficulties in lay-out of the gas channel and processing condition are another disadvantages. Liquid gas assisted injection molding (LGAIM), in which a liquid with a boiling point lower than the temperature of the polymer melt is injected into the melt stream, and travels with the melt into the mold where it vaporizes and pushes the melt downstream and against the cavity walls to create hollow channels within the part, is a good alternative of the conventional gas assisted injection molding especially in manufacturing simple and very thick parts. Though this is a new frontier of the innovation in the injection molding industry, there is no guideline for the design and processing conditions. In this paper, theoretical analysis has been made to describe the hollow formation dynamics in LGAIM. This model provides an insight into LGAIM process: explains why LGAIM has advantages over conventional gas assisted injection molding, and gives a guideline for the design and processing conditions.
  1. Ahn KH, Kim DH, Polym. Eng. Sci., 38(10), 1708 (1998) 
  2. Chao SM, Wang SM, Chen SC, Gao F, Int. Commun. Heat Mass Transf., 26(1), 85 (1999) 
  3. Chen SC, Cheng NT, Int. Commun. Heat Mass Transf., 23(2), 215 (1996) 
  4. Kim DH, Polym. Sci. Technol., 7(3), 303 (1996)
  5. Kim DH, Ahn KH, J. Reinforced Plast. Compos., 17(10), 893 (1998)
  6. Michaeli RC, Kaufmann H, Grief H, Kretzschmar G, Bertuleit R, Training in Injection Molding, Hanser Publishers, Munich Vienna New York (1995)
  7. Parvez MA, Ong NS, Lam YC, Tor SB, J. Mater. Proc. Tech., 121, 27 (2002) 
  8. Polinski AJ, Stokess VK, SPE ANTEC Tech. Papers, 39, 68 (1993)
  9. Shen YK, Int. Commun. Heat Mass Transf., 28(1), 139 (2001) 
  10. Stevenson JF, Innovation in Polymer Processing: Molding, Carl Hanser Verlag (1996)