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

Trung, Thanh; Son, Tran Anh; Minh, Pham Son

doi:10.1155/2019/5973403

Cited by 16 publications

(6 citation statements)

References 17 publications

(47 reference statements)

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“…Several methodologies can be adopted for controlling cavity surface temperature during the injection molding process, such as proximity heating [28,29], infrared heating [30], and electrical heating [31,32]. Another possibility to control the mold temperature was proposed by Minh and coworkers [33], who developed an external gas-assisted mold temperature control for improving the performance of thin rib parts.…”

Section: Introductionmentioning

confidence: 99%

Effect of Rapid Mold Heating on the Structure and Performance of Injection-Molded Polypropylene

et al. 2020

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The tailoring by the process of the properties developed in the plastic objects is the more effective way to improve the sustainability of the plastic objects. The possibility to tailor to the final use the properties developed within the molded object requires further understanding of the relationship between the properties of the plastic objects and the process conduction. One of the main process parameters that allow adjusting the properties of molded objects is the mold temperature. In this work, a thin electrical heater was located below the cavity surface in order to obtain rapid and localized surface heating/cooling cycles during the injection molding process. An isotactic polypropylene was adopted for the molding tests, during which surface temperature was modulated in terms of values and heating times. The modulation of the cavity temperature was found able to control the distribution of relevant morphological characteristics, thus, properties along the sample thickness. In particular, lamellar thickness, crystallinity distribution, and orientation were analyzed by synchrotron X-ray experiments, and the morphology and elastic modulus were characterized by atomic force microscopy acquisitions carried out with a tool for the simultaneous nanomechanical characterization. The crystalline degree slightly increased with the cavity temperature, and this induced an increase in the elastic modulus when high temperatures were adopted for the cavity surface. The cavity temperature strongly influenced the orientation distribution that, on its turn, determined the highest values of the elastic modulus found in the shear layer. Furthermore, although the sample core, not experiencing a strong flow field, was not characterized by high levels of orientation, it might show high values of the elastic modulus if temperature and time during crystallization were sufficient. In particular, if the macromolecules spent adequate time at temperatures close to the crystallization temperature, they could achieve high levels of structuring and, thus, high values of elastic modulus.

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Section: Introductionmentioning

confidence: 99%

Effect of Rapid Mold Heating on the Structure and Performance of Injection-Molded Polypropylene

et al. 2020

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“…The gas-assisted method also controls mold temperature, which shows an impressive effect on the injection process, especially with the thin product. With the gas-assisted method, mold temperature reached 158.4 • C in 20 s and the flow length increased from 37.85~41.32 mm with PP plastic and 14.54~15.8 mm with ABS plastic [6]. Hot gas heating could also improve the filling ratio on the microgroove by up to 91% [7].…”

Section: Introductionmentioning

confidence: 99%

“…The original material shapes for the AM method are powder or wire, and they are melted and adhered to generate the designed forms. Powder materials require a laser beam or electron beam, which are expensive and high-energy consumption devices, despite the fact that they could build high-resolution parts [4][5][6][7][8]. Compared to powder materials, wire shapes have the merits of saving fusion energy and time during the additive process.…”

Section: Introductionmentioning

confidence: 99%

Conformal Cooling Channel Design for Improving Temperature Distribution on the Cavity Surface in the Injection Molding Process

et al. 2023

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Mold heating is an essential process in plastic injection molding. Raising the temperature of the mold before injecting liquefied plastic can ease the mold-filling process. A cooling channel can be used to transport high-temperature fluids for this purpose, such as hot water or oil. This dual purpose is a cost-effective solution for heating the mold because the target temperature is easily achieved using this method. In addition, a conformal cooling channel (CCC) can provide more efficient mold heating than a straight cooling channel. This study used the response surface methodology to determine the optimum CCC shape for heat distribution in a mold, and the simulation results confirmed its optimization. The average temperature of the mold using a CCC was better than that using a straight cooling channel, and the heat zone was uniform across the mold surface.

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“…Instead of heating the entire mold cavity volume, in recent years, many researchers have suggested the use of the mold surface heating method for molding with high cavity temperatures, such as in induction heating [17][18][19][20], high-frequency proximity heating [21,22], and gas-assisted mold temperature control (GMTC) [23][24][25][26][27][28][29][30]. The first two methods support a fast heating rate with a fairly good prediction ability.…”

Section: Introductionmentioning

confidence: 99%

The Feasibility of an Internal Gas-Assisted Heating Method for Improving the Melt Filling Ability of Polyamide 6 Thermoplastic Composites in a Thin Wall Injection Molding Process

2021

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In thin wall injection molding, the filling of plastic material into the cavity will be restricted by the frozen layer due to the quick cooling of the hot melt when it contacts with the lower temperature surface of the cavity. This problem is heightened in composite material, which has a higher viscosity than pure plastic. In this paper, to reduce the frozen layer as well as improve the filling ability of polyamide 6 reinforced with 30 wt.% glass fiber (PA6/GF30%) in the thin wall injection molding process, a preheating step with the internal gas heating method was applied to heat the cavity surface to a high temperature, and then, the filling step was commenced. In this study, the filling ability of PA6/GF30% was studied with a melt flow thickness varying from 0.1 to 0.5 mm. To improve the filling ability, the mold temperature control technique was applied. In this study, an internal gas-assisted mold temperature control (In-GMTC) using different levels of mold insert thickness and gas temperatures to achieve rapid mold surface temperature control was established. The heating process was observed using an infrared camera and estimated by the temperature distribution and the heating rate. Then, the In-GMTC was employed to produce a thin product by an injection molding process with the In-GMTC system. The simulation results show that with agas temperature of 300 °C, the cavity surface could be heated under a heating rate that varied from 23.5 to 24.5 °C/s in the first 2 s. Then, the heating rate decreased. After the heating process was completed, the cavity temperature was varied from 83.8 to about 164.5 °C. In-GMTC was also used for the injection molding process with a part thickness that varied from 0.1 to 0.5 mm. The results show that with In-GMTC, the filling ability of composite material clearly increased from 2.8 to 18.6 mm with a flow thickness of 0.1 mm.

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

Cited by 16 publications

References 17 publications

Effect of Rapid Mold Heating on the Structure and Performance of Injection-Molded Polypropylene

Effect of Rapid Mold Heating on the Structure and Performance of Injection-Molded Polypropylene

Conformal Cooling Channel Design for Improving Temperature Distribution on the Cavity Surface in the Injection Molding Process

The Feasibility of an Internal Gas-Assisted Heating Method for Improving the Melt Filling Ability of Polyamide 6 Thermoplastic Composites in a Thin Wall Injection Molding Process

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