Predicting the Skin-Core Boundary Location in Injection Moldings
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A. M. Brito
Abstract
Over the past few years a technique for relating the quality and properties of sub-components to those of real injection moldings has been developed. A major aspect of this is the correlation of microstructure in the two situations. This paper describes the computer prediction of structure development in injection molded polypropylene. This is done on a personal computer using a finite difference method and it is shown that accurate predictions can be made in relatively low computing time. The characteristic skin in polypropylene moldings is shown to be controlled by the filling phase and is dependent on the shear stress and temperature. The computer model is able to predict the onset of skin formation and hence the skin thickness. These predictions have been shown to agree well with experimental observations. The skin-core boundary which has been found to have a major effect on the mechanical properties of molded polypropylene has also been shown to lie between the no-flow isothermal and the maximum shear rate locus. This has important implications for computer simulations of the injection molding process.
© 1991, Carl Hanser Verlag, Munich
Articles in the same Issue
- Contents
- Contents
- Review Paper
- Existing Scale-up Rules for Single-screw Plasticating Extruders
- Internal Mixers
- Scale-up Effect in Internal Mixers
- Mixing and Extrusion of High Silica and all Silica-natural Rubber Compounds
- Screw Extrusion
- An Analytical Model of Partial and Thorough Melting in Single-screw Extruders
- Dimensionless Non-Newtonian Isothermal Simulation and Scale-up Considerations for Modular Intermeshing Corotating Twin Screw Extruders
- Erratum
- Die Extrusion
- Extrusion of Rubber Compounds and Highly Filled Thermoplastics through Coathanger Dies
- Pressure Oscillations during Capillary Extrusion of High Density Polyethylene
- Frequency Analysis of Pressure Fluctuations in a Single Screw Extruder
- Fibers and Films
- Orientation and Mechanical Property Development in the Melt Spinning of Fibers from Polyetherimide and Polyarylate
- Study on the Formation of β-Crystalline from Isotactic Polypropylene Fiber
- Biaxially-oriented Polyethylene Films by Compression of Injected Moldings
- Modelling of the Cooling of Semi-crystalline Polymers during their Processing
- Molding
- Non-isothermal Mold Filling and Curing Simulation in Thin Cavities with Preplaced Fiber Mats
- Predicting the Skin-Core Boundary Location in Injection Moldings
Articles in the same Issue
- Contents
- Contents
- Review Paper
- Existing Scale-up Rules for Single-screw Plasticating Extruders
- Internal Mixers
- Scale-up Effect in Internal Mixers
- Mixing and Extrusion of High Silica and all Silica-natural Rubber Compounds
- Screw Extrusion
- An Analytical Model of Partial and Thorough Melting in Single-screw Extruders
- Dimensionless Non-Newtonian Isothermal Simulation and Scale-up Considerations for Modular Intermeshing Corotating Twin Screw Extruders
- Erratum
- Die Extrusion
- Extrusion of Rubber Compounds and Highly Filled Thermoplastics through Coathanger Dies
- Pressure Oscillations during Capillary Extrusion of High Density Polyethylene
- Frequency Analysis of Pressure Fluctuations in a Single Screw Extruder
- Fibers and Films
- Orientation and Mechanical Property Development in the Melt Spinning of Fibers from Polyetherimide and Polyarylate
- Study on the Formation of β-Crystalline from Isotactic Polypropylene Fiber
- Biaxially-oriented Polyethylene Films by Compression of Injected Moldings
- Modelling of the Cooling of Semi-crystalline Polymers during their Processing
- Molding
- Non-isothermal Mold Filling and Curing Simulation in Thin Cavities with Preplaced Fiber Mats
- Predicting the Skin-Core Boundary Location in Injection Moldings
