A Low Force Valve for Dynamic Control of Molten Plastics in a Mold
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D. O. Kazmer
Abstract
Polymer processing has been limited by the lack of direct flow and pressure control of the polymer melt at multiple points in space and time. Improved axial and radial valve designs are discussed that require negligible actuation force to control the flow of the pressurized melt. The forces resulting from pressure loads and shear stresses are first analyzed for an axial valve pin. Subsequently, a radial valve design is implemented and experimentally characterized using neat polycarbonate. A sigmoidal response surface is fit to the experimental data and found to very well model the observed pressure drop as a function of flow rate and valve pin position. The juncture loss at the valve port is then characterized by estimating and removing the pressure drops in the circular flow segments of the valve. Analysis indicated that the juncture loss is inversely proportional to the exposed area, or vesica piscis, formed between the circular flow channel in the valve body and the flow port on the moving valve pin. While applicable to many different polymer processing operations, the validated models are used to show the dynamic valve pin position as a function of the desired flow rate and desired cavity pressure in the hot runner of an injection mold. Finally, the impact of the designs on lower power, more compact mechanical and control system designs are discussed.
References
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© 2006, Hanser Publishers, Munich
Articles in the same Issue
- Contents
- Contents
- Regular Contributed Articles
- Pressure and Temperature Dependence of LDPE Viscosity and Free Volume: The Effect of Molecular Structure
- Correlations between Injection Molding Parameters, Morphology and Mechanical Properties of PPS Using Artificial Neural Networks
- Investigations into Kinematic Reversal in Non-isothermal Flows in Single-screw Machines
- The Effect of Post-extrusion Conditions in Ribbon Extrusion of Polymer Blends
- Effect of the Chemical and Morphological Conditions of the Die Wall on the Extrusion of Linear Polyolefins
- Investigation of the Heat Affected Zone of Hot-gas Welded PP Joints
- Method for the Optimisation of Screw Elements for Tightly Intermeshing, Co-rotating Twin Screw Extruders
- Rheology and Processing of Molten Poly(methyl methacrylate) Resins
- PLLA Morphology Controlled by Dry-cast Process
- Two Component Injection Molding of Phase Separating Blends
- A Low Force Valve for Dynamic Control of Molten Plastics in a Mold
- Influence of Drawing and Temperature on the Optical and Structural Properties of Monofilament PP Sutures
- Mechanical Properties of Rubber-toughened Post-industrial Glass-fiber-reinforced PA66
- Thermal Flow Instability in Metal Injection Molding: Experiment and Simulation
- Review Paper
- State of the Art: Recycling of EPDM Rubber Vulcanizates
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
Articles in the same Issue
- Contents
- Contents
- Regular Contributed Articles
- Pressure and Temperature Dependence of LDPE Viscosity and Free Volume: The Effect of Molecular Structure
- Correlations between Injection Molding Parameters, Morphology and Mechanical Properties of PPS Using Artificial Neural Networks
- Investigations into Kinematic Reversal in Non-isothermal Flows in Single-screw Machines
- The Effect of Post-extrusion Conditions in Ribbon Extrusion of Polymer Blends
- Effect of the Chemical and Morphological Conditions of the Die Wall on the Extrusion of Linear Polyolefins
- Investigation of the Heat Affected Zone of Hot-gas Welded PP Joints
- Method for the Optimisation of Screw Elements for Tightly Intermeshing, Co-rotating Twin Screw Extruders
- Rheology and Processing of Molten Poly(methyl methacrylate) Resins
- PLLA Morphology Controlled by Dry-cast Process
- Two Component Injection Molding of Phase Separating Blends
- A Low Force Valve for Dynamic Control of Molten Plastics in a Mold
- Influence of Drawing and Temperature on the Optical and Structural Properties of Monofilament PP Sutures
- Mechanical Properties of Rubber-toughened Post-industrial Glass-fiber-reinforced PA66
- Thermal Flow Instability in Metal Injection Molding: Experiment and Simulation
- Review Paper
- State of the Art: Recycling of EPDM Rubber Vulcanizates
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
