Passive mold temperature control by a hybrid filming-microcellular injection molding processing

2008 ◽  
Vol 35 (7) ◽  
pp. 822-827 ◽  
Author(s):  
Shia-Chung Chen ◽  
Hai-Mei Li ◽  
Shyh-Shin Hwang ◽  
Ho-Hsiang Wang
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Microcellular Injection Molding

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 294-299 ◽  
Author(s):  
Zhi Bian ◽  
Peng Cheng Xie ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Process Conditions ◽  
Fiber Reinforced ◽  
Injection Speed ◽  
Glass Fiber Reinforced ◽  
Microcellular Injection Molding ◽  
Molded Parts

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically significant main and two-factor interaction effects, the results showed that the supercritical fluid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.

Dynamic Mold Temperature Control Using Gas-Assisted Heating and Its Effect on the Molding Replication Qualities of Micro Channels

2008 ◽  
Author(s):  
Shia-Chung Chen ◽  
Yaw-Jen Chang ◽  
Jen-An Chang ◽  
Hsin-Shu Peng ◽  
Ying-Chieh Wang
Keyword(s):  
Injection Molding ◽  
Surface Temperature ◽  
Temperature Control ◽  
Heating System ◽  
Mold Temperature ◽  
Mold Surface ◽  
Water Heating ◽  
Molded Part ◽  
Micro Channels ◽  
Gas Heating

Dynamic mold surface temperature control (DMTC) has the advantage of improving molded part qualities without significant increases in cycle time. A gas-assisted heating system combined with water cooling was developed to achieve DMTC for injection molding. With gas-assisted heating, it takes 2s for the mold surface temperature to vary from 60 °C to 120 °C whereas it requires 186s using water heating. Further, it takes 21s and 84s for the mold surface to cool to 60 °C under gas heating and water heating, respectively. The gas-assisted heating system also shows excellent efficiency for micro injection molding of biochips to achieve high replication accuracy of the micro channels.

scholarly journals Study on External Gas-Assisted Mold Temperature Control for Improving the Melt Flow Length of Thin Rib Products in the Injection Molding Process

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Phan The Nhan ◽  
Thanh Trung Do ◽  
Tran Anh Son ◽  
Pham Son Minh
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
High Efficiency ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Thin Wall ◽  
Mold Surface ◽  
Melt Flow ◽  
Molding Process ◽  
Flow Length

In the injection molding process, mold temperature control is one of the most efficient methods for improving product quality. In this research, an external gas-assisted mold temperature control (Ex-GMTC) with gas temperature variation from 200°C to 400°C was applied to thin wall injection molding at melt thicknesses from 0.2 to 0.6 mm. The melt flow length was evaluated through the application of this system to the mold of a thin rib product. The results show that the heating process achieves high efficiency in the initial 20 s, with a maximum heating rate of 6.4°C/s. In this case, the mold surface reached 158.4°C. By applying Ex-GMTC to a 0.2 mm flow thickness, the flow length increased from 37.85 to 41.32 mm with polypropylene (PP) material and from 14.54 to 15.8 mm with acrylonitrile butadiene styrene (ABS) material. With the thin rib mold and use of Ex-GMTC, the mold temperature varied from 112.0°C to 140.8°C and the thin rib height reached 7.0 mm.

scholarly journals The feasibility of external gas-assisted mold-temperature control for thin-wall injection molding

2018 ◽  
Vol 10 (10) ◽  
pp. 168781401880610 ◽  
Author(s):  
Pham Son Minh ◽  
Thanh Trung Do ◽  
Tran Minh The Uyen
Keyword(s):  
Temperature Distribution ◽  
Injection Molding ◽  
Heating Rate ◽  
Temperature Control ◽  
Mold Temperature ◽  
Cavity Surface ◽  
Thin Wall ◽  
Mold Surface ◽  
Hot Gas ◽  
Wall Injection

Simulation and experimental testing were conducted on an external gas-assisted mold-temperature control combined with a pulsed cooling system used for thin-wall injection molding to determine its effect on the heating rate and temperature distribution of a mold surface. For mold heating via external gas-assisted mold-temperature control, a hot gas was directly discharged on the cavity surface. Based on the heat convection between the hot gas and the cavity surface, the cavity temperature rose to the target value. Practically, the gap between the heating surface and the gas gate is an important parameter as it strongly influences the heating process. Therefore, this parameter was analyzed under different values of plate-insert thickness herein. Heating was elucidated by the temperature distribution and heating-rate data detected by the infrared camera and sensors. Then, external gas-assisted mold-temperature control was applied for the thin-wall injection-molding part of 0.5 mm thickness with the local-gate-temperature control. The results show that with 300°C gas temperature, the heating rate could reach 9°C/s with a 0.5-mm stamp thickness and a 4-mm gas gap. The results show that with local heating at the melt-entrance area of the mold plate, the cavity was filled with a 20-s heating cycle.

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