Influence of Fill Imbalance on Pressure Drop in Injection Molding

  • Przemyslaw PoszwaEmail author
  • Pawel Brzek
  • Pawel Muszynski
  • Marek Szostak
Conference paper
Part of the Lecture Notes in Mechanical Engineering book series (LNME)


During injection molding process melted polymer is introduced into mold cavity due to the pressure delivered from injection unit. Mold design principles suggests that filling of the cavity should be balanced. It means that the furthest regions of cavity (measured from injection point) should be filled at the same time to avoid problems with differential shrinkage and injection pressure drop. Fill imbalance can lead to the significant increase of pressure drop and needed clamp force, that can be compensated with more powereful injection molding machines. In this paper the relation between fill imbalance and injection pressure needed for cavity filling were investigated with Autodesk Moldflow Insight software. In this research several different shapes with thickness change of analyzed parts were performed to measure the significance of imbalance on injection pressure drop. It was found that it is possible to find a gate location even for geometrically imbalanced part, where significant pressure drop reduction can be obtained. Additionally, It was found that lowering V/P switchover point can provide significant reduction of needed injection pressure even if gate location must be placed in unfavorable location


Injection molding Fill imbalance Cavity pressure Plastics 


  1. 1.
    Mrozek, K., Chen, S.C.: Selective induction heating to eliminate the fundamental defects of thin-walled moldings used in electrical industry. J. Appl. Polym. Sci. 134(26), 44992 (2017)CrossRefGoogle Scholar
  2. 2.
    Baesso, R., Salvador, M., Lucchetta, G.: Filling balance optimization for plastics injection molding. In: Advanced Manufacturing Systems and Technology, AMST 2005, pp. 617–624 (2005)Google Scholar
  3. 3.
    Huang, M.S.: Cavity pressure based grey prediction of the filling-to-packing switchover point for injection molding. J. Mater. Process. Technol. 183(2–3), 419–424 (2007)CrossRefGoogle Scholar
  4. 4.
    Kazmer, D.O., Velusamy, S., Westerdale, S., Johnston, S., Gao, R.X.: A comparison of seven filling to packing switchover methods for injection molding. Polym. Eng. Sci. 50(10), 2031–2043 (2010)CrossRefGoogle Scholar
  5. 5.
    Chen, Z., Turng, L.H., Wang, K.K.: Adaptive online quality control for injection-molding by monitoring and controlling mold separation. Polym. Eng. Sci. 46(5), 569–580 (2006)CrossRefGoogle Scholar
  6. 6.
    Kim, J., Ahn, S., Atre, S.V., Park, S.J., Kang, T.G., German, R.M.: Imbalance filling of multi-cavity tooling during powder injection molding. Powder Technol. 257, 124–131 (2014)CrossRefGoogle Scholar
  7. 7.
    Kazmer, O.D.: Injection Mold Desing Engineering. Hanser, Munich (2007)CrossRefGoogle Scholar
  8. 8.
    Beamont, J.P.: Runner and Gating Design Handbook – Tool for Successful Injection Molding, 2nd edn. Hanser, Munich (2007)Google Scholar
  9. 9.
    Poszwa, P., Brzek, P., Szostak, M.: Influence of proces parameters and runner geometry on shear heating effect. Mechanik 1, 36–38 (2018)CrossRefGoogle Scholar
  10. 10.
    Autodesk Inc. Moldflow Insight – Process Simulation Software. Accessed 17 Mar 2018

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Przemyslaw Poszwa
    • 1
    Email author
  • Pawel Brzek
    • 1
  • Pawel Muszynski
    • 1
  • Marek Szostak
    • 1
  1. 1.Poznan University of TechnologyPoznanPoland

Personalised recommendations