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

Giang, Nguyen Truong; Minh, Pham Son; Son, Tran Anh; Nguyen, Hai Thanh; Dang, Hung-Son

doi:10.3390/ma14040965

Cited by 17 publications

(13 citation statements)

References 24 publications

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“…Shorten holding time pressure can affect the flow ability of feedstock during injection process as well. As stated by Giang et al[22],…”

mentioning

confidence: 85%

Thermal and Flow Analysis of Stainless Steel and Alumina Feedstock Used for 2C-PIM Process

Morni¹,

Ismail²,

Nor³

et al. 2022

JMechE

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Within this research, rheological analysis and thermal properties of two component feedstock based on ceramic and metallic powders are carried out to understand their flow behaviour. Scanning electron microscopy (SEM), Differential Scanning Calorimeter (DSC), Thermogravimetric (TGA) and Capillary Rheometer were employed to set up optimum conditions for moulding, debinding and sintering process. DSC results defined the melting point for both backbone binder components were recorded at the same point, 55 oC. TGA results showed total weight loss of alumina and stainless steel feedstock was 17.4% and 6.43% respectively. Throughout rheological analysis, both feedstock exhibit pseudoplastic behaviour as viscosity reduce with the increase of shear rate, with shear sensitivity index less than 1. The activation energy, E for alumina and stainless steel feedstock had E values in the range of 101.93 - 2934.3 J/mol and 7132.3 - 10436 J/mol, respectively. For both alumina and stainless steel feedstock, high mouldability index occurred at the highest temperature with shear rate of 96 s-1 and 4070 s-1 which had the value of 47 x 103 and 24 x 103 respectively. The optimum injection temperature for stainless steel and alumina feedstock should be 190 °C and 230 °C respectively, since the feedstock exhibits the best characteristics for injection.

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“…Shorten holding time pressure can affect the flow ability of feedstock during injection process as well. As stated by Giang et al[22],…”

mentioning

confidence: 85%

Thermal and Flow Analysis of Stainless Steel and Alumina Feedstock Used for 2C-PIM Process

Morni¹,

Ismail²,

Nor³

et al. 2022

JMechE

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show abstract

“…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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“…The authors obtained better strength properties of the material by increasing the temperature of the selected area. Giang et al proposed the injection molding technology with assisting gas in their work [ 24 ]. The simulations and experiments were carried out in air temperatures of 400 °C and a heating time of 20 s to test a device used to focus the flow, which supports external control of the injection mold’s temperature.…”

Section: Introductionmentioning

confidence: 99%

Application of Selective Induction Heating for Improvement of Mechanical Properties of Elastic Hinges

et al. 2021

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Injection molding is a polymer processing technology used for manufacturing parts with elastic hinges. Elastic hinges are widely used in FMCG (Fast Moving Consumer Goods) packaging (e.g., bottle closures of shampoos, sauces) and in the electrical engineering industry. Elastic hinge is a thin film that connect two regions of the injection molded part, where significant shear rates are present, which can lead to the degradation of polymers and the decrease in mechanical properties. Selective induction heating is the method that improves the flow of the polymer melt through thin regions by the local increase in mold temperature. In this study, selective induction heating was used to improve mechanical properties of elastic hinges by the reduction of material degradation due to high shear rates. To verify the change of shear rates, selective induction heating simulation and injection molding simulations were performed. The linear relation between mold temperature and maximum shear rate in the cross-section was identified and the mechanical tests showed significant differences in hinge stiffness, tensile strength and elongation at break.

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

Cited by 17 publications

References 24 publications

Thermal and Flow Analysis of Stainless Steel and Alumina Feedstock Used for 2C-PIM Process

Thermal and Flow Analysis of Stainless Steel and Alumina Feedstock Used for 2C-PIM 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

Application of Selective Induction Heating for Improvement of Mechanical Properties of Elastic Hinges

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