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Injection Molding without Packing

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Published/Copyright: May 27, 2013
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International Polymer Processing
From the journal International Polymer Processing Volume 3 Issue 4

Abstract

By injection molding two kinds of frozen-in orientation will arise: During the filling phase the outer layers of the molding will be sheared and simultaneously cooled. This results in highly oriented layers at the outside of the molding (orientation by filling). During the packing phase the melt, forced into the cavity, gives rise to low rates of deformation in the molding, but since the viscosity has become high by cooling, high stresses and frozen-in orientation will also result (orientation by packing). This last kind of orientation can be avoided by high pressures in the filling phase, followed by immediate mechanical sealing of the cavity (injection molding without packing), and hereby a better quality of the moldings can be achieved. Some results with moldings of PS and PP are given.

* Mail address: Professor Dr. W. Knappe, Institut für Kunststoffverarbeitung, Montanuniversität Leoben, Franz Josef Str. 18, 8700 Leoben, Austria
Published Online: 2013-05-27
Published in Print: 1988-12-01

© 1988, Carl Hanser Verlag, Munich

Articles in the same Issue

  1. Contents
  2. Contents
  3. Original Contributions
  4. On Dispersed Crystallization in Polymer Melts as Proceeding from a Quenched Boundary
  5. Modelling the Packing Cooling Stage in Injection Molding of Amorphous Polymers
  6. Injection Molding without Packing
  7. System Analysis and Morphological Classification of Procedures and Molds for Injection Molding
  8. Simultaneous Interpenetrating Networks of Polybutadiene-based Polyurethane/Poly (Methyl Methacrylate-co-Glycol Dimethacrylate)
  9. The Processing and Properties of γ-irradiated HDPE Granules
  10. Dynamic Measurements on Polymer Liquid Crystals**
  11. DSC Studies on Fibre-Filled Polyethylene
https://doi.org/10.3139/217.880191

Articles in the same Issue

  1. Contents
  2. Contents
  3. Original Contributions
  4. On Dispersed Crystallization in Polymer Melts as Proceeding from a Quenched Boundary
  5. Modelling the Packing Cooling Stage in Injection Molding of Amorphous Polymers
  6. Injection Molding without Packing
  7. System Analysis and Morphological Classification of Procedures and Molds for Injection Molding
  8. Simultaneous Interpenetrating Networks of Polybutadiene-based Polyurethane/Poly (Methyl Methacrylate-co-Glycol Dimethacrylate)
  9. The Processing and Properties of γ-irradiated HDPE Granules
  10. Dynamic Measurements on Polymer Liquid Crystals**
  11. DSC Studies on Fibre-Filled Polyethylene
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