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Injection Moulding of Thermoplastic Polymers

  • M. Vincent
Chapter
  • 466 Downloads
Part of the NATO ASI Series book series (NSSE, volume 302)

Abstract

The injection moulding of thermoplastic materials can be divided into the following steps :
  • plastication in a screw-barrel system

  • filling of the cav ity : us u ally, the flow rate is imposed, w ith a constant value, or with successive steps with different flow rates. Sometimes a limit of the pressure is specifiied by the operator, so that the end of filling is at constant pressure

  • packing-holding : the pressure at the entrance of the cavity is now imposed, and an extra flow of material compensates the thermal shrinkage

  • cooling in the mould : this step begins when the gate is frozen, although, of course, the polymer is cooled as soon as it enters the cavity which is kept usually around the room temperature.

  • ejection

  • cooling outside the mould

Keywords

Residual Stress Injection Molding Injection Moulding Filling Stage Flow Front 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Magnin, B. (1994) Modélisation du remplissage des moules d’injection pour polymères thermoplastiques par une méthode Eulerienne-Lagrangienne arbitraire, Ph.D. Thesis, Ecole des Mines de Paris, FranceGoogle Scholar
  2. 2.
    Ballman, R.L., Shusman, T., and Toor, H.L. (1959) Injection molding : flow of a molten polymer into a cold cavity, Ind. Eng. Chem 51, 847CrossRefGoogle Scholar
  3. 3.
    Harry, D.H. and Parrott, R.G. (1970) Numerical simulation of injection mold filling, Polym. Eng. Sci. 10, 209–214CrossRefGoogle Scholar
  4. 4.
    White, J.L. (1975) Fluid mechanical analysis of injection mold filling, Polym. Eng. Sci. 15, 44–50CrossRefGoogle Scholar
  5. 5.
    Thienel, P. and Menges, G. (1978) Mathematical and experimental determination of temperature, velocity, and pressure fields in flat molds during the filling process in injection molding of thermopastics, Polvm. Eng. Sci. 18, 314–320CrossRefGoogle Scholar
  6. 6.
    Agassant, J.F., Alles, H., Philipon, S., and Vincent, M. (1988) Experimental and theoretical study of the injection molding of thermoplastic materials, Polym. Eng. Sci. 28, 460–468CrossRefGoogle Scholar
  7. 7.
    Kamal, M.R. and Kenig, S. (1972) The injection molding of thermoplastics part I and II, Polym. Eng. Sci. 12, 294–308CrossRefGoogle Scholar
  8. 8.
    Berger, J.L. and Gogos, C.G. (1973) A numerical simulation of the cavity filling process with PVC in injection molding, Polym. Eng. Sci. 13, 102–112CrossRefGoogle Scholar
  9. 9.
    Gutfinger, C., Broyer, E., and Tadmor, Z. (1975) Melt solidification in polymer processing, Polym. Eng. Sci. 15, 515–524CrossRefGoogle Scholar
  10. 10.
    Vincent, M. (1984) Etude de l’orientation des fibres de verre courtes lors de la mise en oeuvre de thermoplastiques chargés, Ph.D. Thesis, Ecole des Mines de Paris, FranceGoogle Scholar
  11. 11.
    Williams, G. and Lord, H.A. (1975) Mold filling studies for the injection molding of thermoplastic materials, Polym. Eng. Sci. 15, 553–582CrossRefGoogle Scholar
  12. 12.
    Nunn, R.E. and Fenner, R.T. (1977) Flow and heat transfer in the nozzle of an injection molding machine, Polym. Eng. Sci. 17, 811–820CrossRefGoogle Scholar
  13. 13.
    Hieber, C.A. (1982) Coupled flow path method for simulating the injection moulding filling stage, SPE Antec Tech. Papers 28, 356–358Google Scholar
  14. 14.
    Ghoneim H. (1987) Simulation of balancing multi-cavity molds, Int. Polym. Proc. 4, 166–173Google Scholar
  15. 15.
    Stevenson, J.F. and Chuck, W. (1979) A simplified method for analyzing mold filling dynamics, Polym. Eng. Sci. 19, 849–857CrossRefGoogle Scholar
  16. 16.
    Richiardson, S.M., Pearson, H.J., and Pearson, J.R.A. (1980) Simulation of injection molding, Plastics and Rubber Processing 55, 55–60Google Scholar
  17. 17.
    Broyer, E., Gutfinger, C., and Tadmor, Z. (1975) Theoretical model for the cavity filling process in injection moulding, Trans. Soc. Rheol. 19, 423–444CrossRefGoogle Scholar
  18. 18.
    Hieber, C.A. and Shen, S.F. (1978) Flow analysis of the nonisothermal two-dimensional filling process in injection molding, Israel J. Technology 16, 248–254Google Scholar
  19. 19.
    Subbiah, S., Trifford, D.L., and Güceri, S.I. (1989) Nonisothermal flow of polymers inti two-dimensional thin cavity molds : numerical grid generation approach, Int. J. Heat Mass Transfert 32, 415–434CrossRefGoogle Scholar
  20. 20.
    Willien, J.L. (1992) Modélisation surfacique du remplissage de moules en injection des thermoplastiques, Ph.D. Thesis, Ecole des Mines de Paris, FranceGoogle Scholar
  21. 21.
    Couniot, A., Dheur, L., and Dupret, F. (1989) A finite element method for simulating injection molding of thermoplastics, in E.G. Thompson, R.D. Wood, O.C. Zienkiewicz, A. Samuelson (eds), Numerical Methods in Industrial Forming Processes, Balkema, Rotterdam, 235–241Google Scholar
  22. 22.
    Chiang, H.H., Hieber, C.A., and Wang, K.K. (1991) A unified simulation of the filling and postfilling stages in injection molding, Polym. Eng. Sci. 31,116–124CrossRefGoogle Scholar
  23. 23.
    Boshouwers, G. and Van der Werf, J.(1988) Inject-3, a simulation code for the filling stage of the injection moulding process of thermoplastics, Ph.D. Thesis, Technical University Eindhoven, The NetherlandsGoogle Scholar
  24. 24.
    Maillot, I. (1993) Simulation du remplissage compactage pour la mise en forme des thermoplastiques par injection, Ph.D. Thesis, Université Joseph Fourier Grenoble 1, FranceGoogle Scholar
  25. 25.
    Shen, S.F. (1984) Simulation of polymer flows in the injection moulding process, Int. J. Numer. Methods Fluids 4, 171–183ADSzbMATHCrossRefGoogle Scholar
  26. 26.
    Gogos, C.G.i, Huang, C.F., and Schmidt, L.R. (1986) The process of cavity filling including the fountain flow in injection molding, Polym. Eng. Sci. 26, 1457–1466CrossRefGoogle Scholar
  27. 27.
    Lafleur, P.G. and Kamal, M.R. (1986) A structure oriented computer simulation of the injection molding of viscoelastic crystalline polymers, Polym. Eng. Sci. 26, 92–102CrossRefGoogle Scholar
  28. 28.
    Behrens, R.A., Crochet, M.J., Denson, C.D., and Metzner, A.B. (1987) Transient free surface flows : motion of a fluid advancing in a tube, AIChE J. 33, 1178–1186CrossRefGoogle Scholar
  29. 29.
    Fauchon, D., Dannelongue, H.H., and Tanguy, P.A. (1991) Numerical simulation of the advancing front in injection molding, Int. Polym. Proc. 6,13–18Google Scholar
  30. 30.
    Mavridis, H., Hrymak, A.N., and Vlachopoulos, J. (1986) Finite element simulation of fountain flow in injection molding, Polym. Eng. Sci. 26, 449–454CrossRefGoogle Scholar
  31. 31.
    Coyle, D.J., Blake, J.W., and Macosko, C.W. (1987) The kinematics of fountain flow in mold-filling, AIChE J. 33, 1168–1177CrossRefGoogle Scholar
  32. 32.
    Manas-Zloczower, I., Blake, J.W., and Macosko, C.W. (1987) Space-time distribution in filling a mold, Polym. Eng. Sci. 27, 1229–1235CrossRefGoogle Scholar
  33. 33.
    Spencer, R.S. and Gilmore, G.D. (1951) Some flow phenomena in the injection molding of polystyrene, J. Colloid Science. 6, 118–132CrossRefGoogle Scholar
  34. 34.
    Kamal, M.R., Kuo, Y., and Doan, P.H. (1975) The injection molding behavior of thermoplastics in thin rectangular cavities, Polym. Eng. Sci. 22, 1066–1074CrossRefGoogle Scholar
  35. 35.
    Greener, J. (1986) General consequences of the packing phase in injection molding, Polym. Eng. Sci. 26, 886–892CrossRefGoogle Scholar
  36. 36.
    Greener, J. (1986) Pressure induced densification in injection molding, Polym. Eng. Sci. 26, 534–542CrossRefGoogle Scholar
  37. 37.
    Titomanlio, G., Piccarolo, S., and Levati, G. (1988) On the packing-holding flow in the injection molding of thermoplastic polymers, J. App. Polym. Sci. 35, 1483–1495CrossRefGoogle Scholar
  38. 38.
    Chung, T.S. (1985) Pressure build-up during the packing stage of injection molding, Polym. Eng. Sci. 25, 772–777CrossRefGoogle Scholar
  39. 39.
    Hieber, C.A. (1987) Melt viscosity characterisation and its application to injection molding, in A.I. Isayev (ed), Injection and compression molding fundamentals, Marcel Dekker, Inc, New York, Basel, pp.1–136Google Scholar
  40. 40.
    Deterre, R. (1984) Analyse du compactage lors de l’injection des thermoplastiques, Ph.D. Thesis, Louis Pasteur University, Strasbourg, FranceGoogle Scholar
  41. 41.
    Van Krevelen, D.W. (1976) Properties of polymers, 2nd ed., Elsevier, AmsterdamGoogle Scholar
  42. 42.
    Struik, L.C.E. (1978) Orientation effects and cooling stresses in amorphous polymers, Polvm. Eng. Sci. 18, 799–811CrossRefGoogle Scholar
  43. 43.
    Baaijens, F.P.T. (1991) Calculation of residual stresses in injection molded products, Rheol. Acta 30, 284–299CrossRefGoogle Scholar
  44. 44.
    Mills, N.J. (1983) Computation of residual stresses in extruded and injection moulded products, Plastics and Rubber Proc. Applications 3, 181–188Google Scholar
  45. 45.
    Titomanlio, G., Brucato, V., and Kamal, M.R. (1987) Mechanism of cooling stress build-up in injection molding of thermoplastic polymers, Intern. Polym. Processing,1, 55–59Google Scholar
  46. 46.
    Brucato, V., Piccarolo, S., and Titomanlio, G. (1989) Cooling stresses in polystyrene injection molded samples, Materials Engineering,1, 597–604Google Scholar
  47. 47.
    Jansen, K.M.B. (1994) Residual stresses in injection moulded products, Intern. Polym. Processing 9, 82–89Google Scholar
  48. 48.
    Carslaw, H.S., and Jaeger, J.C. (1988) Conduction of heat in solids, Oxford Science Publications, Clarendon Press, OxfordGoogle Scholar
  49. 49.
    Isayev, A.I. (1987) Orientation, residual stresses and volumetric effects in injection molding, in A.I. Isayev (ed), Injection and compression molding fundamentals, Marcel Dekker, Inc Publisher, New-York and Basel, pp. 227–328Google Scholar
  50. 50.
    Treuting, R.G., and Read, W.T. (1951) , J. Appl. Phys. 22, 130-ADSzbMATHCrossRefGoogle Scholar
  51. 51.
    Haworth, B., Hindle, C.S., and Sandilands, G.J. (1982) Plast. Rub. Process. Appl. 2, 59-Google Scholar
  52. 52.
    Siegmann, A., Buchman, A., and Kenig, S. (1982) Residual stresses in polymers, Polym. Eng.Sci. 22, 560–568CrossRefGoogle Scholar
  53. 53.
    Hastenberg, C.H.V., Wildervanck, P.C., Leenen, A.J.H., and Schennink, G.G.J. (1992) The measurement of thermal stresses distributions along the flow path in injection molded flat plates, Polym. Eng. Sci. 2, 506–515CrossRefGoogle Scholar
  54. 54.
    Denizart, O.(1990) Contraintes résiduelles dans les pièces injectées en thermoplastique : approche expérimentale et modélisation, PhD thesis, Ecole des Mines de Paris, FranceGoogle Scholar
  55. 55.
    El-Rafey, E., Abdelkader, A.F., and Kandil, S.H. (1994) Effect of processing conditions on mechanical properties and residual stresses in injection molded amorphous polymer, J. Appl. Polym. Sci., Appl. Polvm. Svmp. 55, 129–137Google Scholar
  56. 56.
    Denizart, O., Vincent, M., and Agassant, J.F. Thermal stresses and strains in injection moulding : experiments and computations, Accepted for publication in J. Mat. Sci. Google Scholar
  57. 57.
    Boitout, F., Agassant, J.F., and Vincent, M. Elastic calculation of residual stresses in injection moulding : influence of mouldGoogle Scholar
  58. 58.
    Douven, L.F.A. (1991) Towards the computation of properties of injection moulded products : flow and thermally induced stresses in amorphous thermoplastics, PhD Thesis, Eindhoven Technical University, Eindhoven, The NetherlandsGoogle Scholar
  59. 59.
    Kabanemi, K.K., and Crochet, M.J. (1992) Thermoviscoelastic calculation of residual stresses and residual shapes of injection molded parts, Intern. Polym. Proc. 7, 60–70Google Scholar
  60. 60.
    Rezayat, M., and Stafford, R.O. (1991) A thermoviscoelastic model for residual stress in injection molded thermoplastic, Polym. Eng. Sci. 31,393–398CrossRefGoogle Scholar
  61. 61.
    Boitout, F. (1993) Calcul des contraintes résiduelles dans les pièces injectées en thermoplastiques en utilisant un description surfacique de la géometrie, PhD Thesis, Ecole des Mines de Paris, FranceGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1995

Authors and Affiliations

  • M. Vincent
    • 1
  1. 1.Centre de Mise en Forme des Matériaux, URA CNRS 1374Ecole des Mines de ParisSophia-Antipolis CedexFrance

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