Nozzle Injection of Physical Blowing Agents in the Injection Molding of Microcellular Foams
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V. L. Bravo
Abstract
Results obtained from the implementation of a physical foaming system for injection molding are presented. The implemented design involves the injection of gas in the upstream side of a special nozzle composed by a static mixing element (SMX type) and a shut-off valve. In order to avoid the formation of large pockets of gas in the injection point, a porous metal plug is used to create a multiple point injection area with 20 lm size pores. Gas injection simultaneously with polymer melt injection gave a consistent foamed material. However, given the total pressure drop in the system of static mixers, runners and mold, there is an inherent operational pressure limitation. The polymer injection pressure needs to be kept at a pressure below the gas injection pressure, therefore limiting the speed at which the polymer can be injected in the mold.
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© 2005, Carl Hanser Verlag, Munich
Articles in the same Issue
- Contents
- Contents
- Editorial
- International Polymer Processing Special Issue Macro 2004
- Invited Paper
- A Dilatometer to Measure the Influence of Cooling Rate and Melt Shearing on Specific Volume
- Monitoring Reactive Processes along the Extruder
- Stretch and Shape Distributions of Droplets with Interfacial Tension in Chaotic Mixing
- Cast Film Extrusion
- Nozzle Injection of Physical Blowing Agents in the Injection Molding of Microcellular Foams
- Visualization Analysis of Asymmetric Fountain Flow Phenomenon in Injection Molding of Filler-reinforced Resins by Rotary Runner Exchange System
- In-process Monitoring of Micromoulding – Assessment of Process Variation
- Processing-induced Properties in Glassy Polymers
- Structure Development in Injection Molding: A 3D Simulation with a Differential Formulation of the Kinetic Equations
- Evolution of Morphology of iPP in Processing Conditions
- Regular Contributed Articles
- 3D Simulation of Gas Assisted Injection Molding Analysis of Primary and Secondary Gas Penetration and Comparison with Experimental Results
- Microcellular Injection Molding
- Effect of Material Species on Flash Generation of PPS/GF Composites
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
Articles in the same Issue
- Contents
- Contents
- Editorial
- International Polymer Processing Special Issue Macro 2004
- Invited Paper
- A Dilatometer to Measure the Influence of Cooling Rate and Melt Shearing on Specific Volume
- Monitoring Reactive Processes along the Extruder
- Stretch and Shape Distributions of Droplets with Interfacial Tension in Chaotic Mixing
- Cast Film Extrusion
- Nozzle Injection of Physical Blowing Agents in the Injection Molding of Microcellular Foams
- Visualization Analysis of Asymmetric Fountain Flow Phenomenon in Injection Molding of Filler-reinforced Resins by Rotary Runner Exchange System
- In-process Monitoring of Micromoulding – Assessment of Process Variation
- Processing-induced Properties in Glassy Polymers
- Structure Development in Injection Molding: A 3D Simulation with a Differential Formulation of the Kinetic Equations
- Evolution of Morphology of iPP in Processing Conditions
- Regular Contributed Articles
- 3D Simulation of Gas Assisted Injection Molding Analysis of Primary and Secondary Gas Penetration and Comparison with Experimental Results
- Microcellular Injection Molding
- Effect of Material Species on Flash Generation of PPS/GF Composites
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
