Optimization of the Weldline Strength in Gas-assist Injection Molded Thermoplastic
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S.-J. Liu
Abstract
Gas assist injection molding has increasingly become an important process in industry because of its tremendous flexibility in the design and manufacture of plastic parts. However, there are some unsolved problems that confound the overall success of this technique. Weldlines success of this technique. Weldlines form wherever polymer flow fronts meet is one of them. In this report, an L'18 experimental matrix design based on the Taguchi method was conducted to optimize the weldline strength of gas assist injection molded thermoplastics. Experiments were carried out on an 80-ton injection molding machine equipped with a high-pressure nitrogen-gas injection unit. A dumbbell-shape mold cavity was used. After molding, the weldline strength of the parts was measured by a tensile tester For the factors selected in the main experiments, melt temperature and mold temperature were found to be the principal factors affecting the weldline property of gas assist injection molded thermoplastics. Weld strength decreases with the length of gas penetration. In addition the weldline strength of gas assist injection molded parts was found to be generally weaker than that of conventional injection molded parts.
© 1999, Carl Hanser Verlag, Munich
Articles in the same Issue
- Editorial
- First of a Series: Pioneering Polymer Industry Developments: Bayer and the First Synthetic RubberFirst of a Series
- Internal Mixer
- Modeling Non-isothermal Mixing in a Rotor Mixer
- Screw Extrusion/Mixing
- Chrome Nitride Coatings for Applications in Plastics Processing
- Using Computational Fluid Dynamics to Investigate the Flow of a Viscous Fluid in a Cavity with Oscillating Boundaries
- Simulation of Flow in an Intermeshing Modular Counter-rotating Twin Screw Extruder: Non-Newtonian and Non-Isothermal Behavior
- Reactive Extrusion
- Bulk and Dispersed Phase Polymerization of Urethane in Twin Screw Extruders
- Die Extrusion
- Wire Coating by Drawdown of an Extruded Annular Melt
- Fibers and Films
- Structure Development in Melt Spinning Polypropylene-EPM Blends and Dynamically Vulcanized Polyolefin TPEs
- Simulation of Blown-Film Process Taking Account of Cooling-air Effect
- Molding
- Analysis of Shrinkage Development of Injection Moulded PS Samples
- Optimization of the Weldline Strength in Gas-assist Injection Molded Thermoplastic
- Injection Velocity Control Using A Self-tuning Adaptive Controller
Articles in the same Issue
- Editorial
- First of a Series: Pioneering Polymer Industry Developments: Bayer and the First Synthetic RubberFirst of a Series
- Internal Mixer
- Modeling Non-isothermal Mixing in a Rotor Mixer
- Screw Extrusion/Mixing
- Chrome Nitride Coatings for Applications in Plastics Processing
- Using Computational Fluid Dynamics to Investigate the Flow of a Viscous Fluid in a Cavity with Oscillating Boundaries
- Simulation of Flow in an Intermeshing Modular Counter-rotating Twin Screw Extruder: Non-Newtonian and Non-Isothermal Behavior
- Reactive Extrusion
- Bulk and Dispersed Phase Polymerization of Urethane in Twin Screw Extruders
- Die Extrusion
- Wire Coating by Drawdown of an Extruded Annular Melt
- Fibers and Films
- Structure Development in Melt Spinning Polypropylene-EPM Blends and Dynamically Vulcanized Polyolefin TPEs
- Simulation of Blown-Film Process Taking Account of Cooling-air Effect
- Molding
- Analysis of Shrinkage Development of Injection Moulded PS Samples
- Optimization of the Weldline Strength in Gas-assist Injection Molded Thermoplastic
- Injection Velocity Control Using A Self-tuning Adaptive Controller
