Search

This study investigates the effects of the vent-area on bubble-microstructure and shrinkage variation of gas-assisted foam-injection molding (GAFIM). The molding material is polystyrene (PS), and the gas foaming agent is nitrogen (N 2 ). This study carried out the injection experiment with and without GAFIM to observe the molding characteristics of gas-filling pressure variation. In addition, the integration of vent-area volumes and cavity pressure measurement was developed to achieve foam growth and microstructure inside the sample to observe the effect of with and without vent-area on shrinkage variation and correlated pressure distribution near gate position during the filling process. The experimental results revealed that with the vent-area, the sample dimension shrinkage was relatively improved and the sample weight was reduced. On the other hand, the bubble-distribution increased with the changes in the volume of the vent-area and gas-filling pressure as the foam growth space increased.

This study used the cavity-surface infrared rapid-heating method and tensile specimens (ASTM-D638) to test the fiber compatibility and tensile characteristics of long glass fiber reinforced PA66 (LGF-PA66) composites. The weldline molding experiment on the injected specimen was conducted using a double-gate. In addition, the integration of infrared heating and cavity pressure measurement were developed to achieve cavity-surface heating and observe the effect of with/without cavity-surf ace heating on weldline tensile strength variation and correlated pressure distribution near the weldline region. On the other hand, a vent -well was designed in the center position of the specimen (vent-well depths are 0.9 mm, 1.8 mm, and 3.6 mm), in order to discuss the effect of the two-melts on fiber and melt compatibility in the compatible process. The experimental results show that vent-well provides better weldline tensile strength; moreover, infrared heating cavity -surface also provides the better weldline tensile strength of LGF-PA66 composites molded parts. In addition, from SEM images and cavity pressure distributions, considering in presence or absence of vent-well design and cavity-surface heating, it provides better weldline tensile strength and interfaces compatibility between fiber and resin at weldline region during molding stage.

PET bottle is an excellent packaging material, is widely used in the food & beverage industry which has further given impetus to the market. With an increasing demand for production capability of PET bottle, the rapid cooling efficiency and uniform temperature distribution are important issue on cooling channel design of blow mold. Due to the insufficient cooling time and non-uniform mold temperature distribution that cause bottle stress cracking or broken. In this study, the conformal cooling channel design is developed to achieve a rapid cooling efficiency and uniform temperature distribution of blow mold. The cooling efficiency and temperature distribution during cooling process was measured using infrared thermal image system and thermocouple sensor. Simulation technology was also developed by integration of thermal and fluid flow analysis modules of ANSYS-FLUENT. For cooling efficiency comparison, the shape and size of the conformal cooling channels, fluid temperature and flow rate were varied for both experiments and simulations. The capability and accuracy of simulation on conformal cooling channel design and analysis were verified via experiments. The simulated cooling efficiency and temperature distribution show reasonable agreement with measured results. A reduction in cooling time from the initial 2.9 seconds to 1 second; moreover, conformal cooling channel provides uniform temperature distribution and less temperature difference of 4°C.

In recent years, due to the raising of green manufacturing and environmental consciousness, the industrial equipment and molded product request toward energy saving, reducing cycle time and secondary process procedure. With high strength, high stiffness, high design possibility, better fatigue life and better corrosion resistance capability, PA66 polymer composite materials are gaining more and more attention in functional products. In this study, PA66 polymer composites material used in slide components molding to replace the original metal material. The results indicated that PA66 polymer composites add 2%wt MoS2 result higher tensile strength and flexural strength than the original polymer material. The value of increased strength of tensile strength is 8% and flexural strength is 27%. In addition, the CAE simulated results are successful to predictive molding characteristics and improve structural strength of molded parts.