Advertisement

The Causes and Prevention of Injection Moulding Defects in Large Ceramic Sections

  • T. Zhang
  • J. R. G. Evans
Chapter

Abstract

During the solidification stage, a range of defects appears in large ceramic sections in conventional injection moulding. These include shrinkage voids and cracks which may appear after storage or reheating. The origins of these defects are being explored experimentally in terms of material properties and machine conditions and quantitatively by computer modelling. Several interventions are described which have in common the objective of eliminating voids without resort to high hold pressures. These include the use of an enlarged sprue, a heated sprue and modulated hold pressure.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Edirisinghe, M.J., Evans, J.R.G., Properties of ceramic injection moulding formulations I. Melt rheology, J. Mater. Sci., 22 2267–73 (1987).CrossRefGoogle Scholar
  2. 2.
    Hunt, K.N., Evans, J.R.G., Woodthorpe, J., Computer modelling of the orlgln of defects in ceramic injection moulding I. Shrinkage voids, J. Mater. Sci., 26 292–300 (1991).CrossRefGoogle Scholar
  3. 3.
    Hunt, K.N., Evans, J.R.G., Mills, N.J., Woodthorpe, J., Computer modelling of the origin of defects in ceramic injection moulding IV. Residual stresses, J. Mater. Sci., in press.Google Scholar
  4. 4.
    Zhang, T., Evans, J.R.G., Dutta, K., Thermal properties of ceramic injection moulding suspensions in the liquid and solid state, J. Euro. Ceram. Soc., 5 303–9 (1989).CrossRefGoogle Scholar
  5. 5.
    Zhang, T., Evans, J.R.G., Thermal expansion and equation of state for ceramic injection moulding suspensions, J. Euro. Ceram. Soc., 5 15–21 (1990).CrossRefGoogle Scholar
  6. 6.
    Zhang, T., Evans, J.R.G., Predicting the viscosity of ceramic injection moulding suspensions, J. Euro. Ceram. Soc., 5 165–172 (1989).CrossRefGoogle Scholar
  7. 7.
    Allan, P.S., Bevis, M.J., Edirisinghe, M.J., Evans, J.R.G., Hornsby, P.R., Avoidance of defects in injetion moulding technical ceramics, J. Mater. Sci., Lett., 6 165–6 (1987).CrossRefGoogle Scholar
  8. 8.
    Hunt, K.N., Evans, J.R.G., A heated sprue bush for ceramic injection moulding, J. Mater. Sci. Lett., in press.Google Scholar
  9. 9.
    Zhang, T., Evans, J.R.G., The calculation of temperature distribution during the solidification stage in ceramic injection moulding, to be published.Google Scholar
  10. 10.
    Zhang, T., Evans, J.R.G., Predicting the voids in ceramic injection moulding, to be published.Google Scholar
  11. 11.
    Allan, P.S., Bevis, M.J., Development and application of multiple live feed moulding for the management of fibres in moulded parts, Composites Manufacturing 1 79-(1990).CrossRefGoogle Scholar

Copyright information

© Elsevier Science Publishers Ltd and MPA Stuttgart 1992

Authors and Affiliations

  • T. Zhang
    • 1
  • J. R. G. Evans
    • 1
  1. 1.Department of Materials TechnologyBrunel UniversityUxbridge, MiddlesexUK

Personalised recommendations