Use of the Fast-cool pVT Data for Shrinkage Analysis in Injection Molding
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S. Han
Abstract
The prediction of shrinkage and warpage of crystalline polymers is quite difficult. This is because of the complications of the crystallization process and associated material property changes. Particularly, the pVT behavior is dependent on the cooling rate during injection molding. Traditionally, the pVT data were measured in a device where the cooling rate is very slow compared to that in the actual injection molding process. This cooling-rate dependent pVT data is considered to affect the shrinkage and warpage calculation significantly. In the present study, a method has been developed to obtain pVT behavior at the same cooling rate as in the actual injection molding process. Obtaining other material data such as viscosity, thermal conductivity and heat capacity at the cooling rate of the actual injection molding process has also been considered.
Injection-molding experiments have been conducted to measure the shrinkage of a part using semi-crystalline polymers. The polymers used in this study are polyamide 66 (PA 66) and polybutylene terephthalate (PBT).
Simulation has been done to calculate the shrinkage using the cooling-rate dependent material properties. Using the fast-cool pVT behavior, the agreement between the simulation and the experiment improved significantly compared to the traditional approach.
© 2002, Carl Hanser Verlag, Munich
Articles in the same Issue
- Editorial
- Twelfth of a Series: Father of Synthetic Fiber Industry Wallace Hume Carothers
- Special Paper
- The Matching of Experimental Polymer Processing Flows to Viscoelastic Numerical Simulation
- Single and Twin Screw Extrusion
- Polymer Pellet Flow out of the Hopper into the First Section of a Single Screw
- Estimation of Residence Time Distribution in two Elements of a Ko-Kneader
- Flow Characteristics of Screws and Special Mixing Enhancers in a Co-rotating Twin Screw Extruder
- Reactive Extrusion
- Bulk Polymerization of ε-Caprolactone in an Internal Mixer and in a Twin Screw Extruder
- Die Extrusion
- Flow Instabilities of Linear PE in Capillary Dies
- In-line Ultrasonic Monitoring of Filler Dispersion during Extrusion
- Fibers and Film
- Birefringence and Mechanical Property Development in Melt Spinning Cyclopolyolefin Filaments
- Injection Molding
- An Empirical Study of the Surface Blush in Gas-Assisted Injection Molded Parts
- Use of the Fast-cool pVT Data for Shrinkage Analysis in Injection Molding
- Composite Processing
- Impregnation Behaviors in Composite Processing
Articles in the same Issue
- Editorial
- Twelfth of a Series: Father of Synthetic Fiber Industry Wallace Hume Carothers
- Special Paper
- The Matching of Experimental Polymer Processing Flows to Viscoelastic Numerical Simulation
- Single and Twin Screw Extrusion
- Polymer Pellet Flow out of the Hopper into the First Section of a Single Screw
- Estimation of Residence Time Distribution in two Elements of a Ko-Kneader
- Flow Characteristics of Screws and Special Mixing Enhancers in a Co-rotating Twin Screw Extruder
- Reactive Extrusion
- Bulk Polymerization of ε-Caprolactone in an Internal Mixer and in a Twin Screw Extruder
- Die Extrusion
- Flow Instabilities of Linear PE in Capillary Dies
- In-line Ultrasonic Monitoring of Filler Dispersion during Extrusion
- Fibers and Film
- Birefringence and Mechanical Property Development in Melt Spinning Cyclopolyolefin Filaments
- Injection Molding
- An Empirical Study of the Surface Blush in Gas-Assisted Injection Molded Parts
- Use of the Fast-cool pVT Data for Shrinkage Analysis in Injection Molding
- Composite Processing
- Impregnation Behaviors in Composite Processing
