Visualization of bubble dynamics in foam injection molding

Mahmoodi, Mehdi; Behravesh, Amir Hossein; Rezavand, Seyed Abdol Mohammad; Pashaei, Amir

doi:10.1002/app.31839

Cited by 24 publications

(22 citation statements)

References 18 publications

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“…Moreover, by using ultrasonics, the foams became smaller and the porosity of the material was higher than the non‐sonicated samples . However, microcellular foams need high pressure and a long time to saturate the gas into the material, and the procedure is complicated, i.e., both gas saturation and high foaming temperature are required . Moreover, after microcellular foaming, the mechanical property of ABS decreased, and a higher sonic power was needed to produce high quality foams (i.e., small cell size and high cell density) .…”

Section: Introductionmentioning

confidence: 99%

Structural, mechanical, and thermal properties of 3D printed L‐CNC/acrylonitrile butadiene styrene nanocomposites

Feng

Yang

Rostom³

et al. 2017

J of Applied Polymer Sci

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3D printing has been extensively applied in human‐related activities, and therefore the 3D printed nanocomposites became more popular and important in end‐use products. In the present study, we use lignin‐coated cellulose nanocrystal (L‐CNC) to reinforce 3D printed acrylonitrile butadiene styrene (ABS) and explore the effect of L‐CNC on the structural, mechanical, and thermal properties of 3D printed L‐CNC/ABS nanocomposites. The results indicate that the addition of L‐CNC foams the ABS and decreases the density of 3D printed L‐CNC/ABS nanocomposites. However, the tensile modulus and storage modulus increase by adding 4% L‐CNC. The thermal stability of 3D printed L‐CNC/ABS nanocomposites is also significantly improved as indicated by an increase in the maximum degradation temperature. The morphology of the nanocomposites reveals good dispersion and interfacial adhesion between L‐CNC and ABS. The finding indicates that the 3D printed nanocomposites become lighter and stiffer with addition of L‐CNC, which will have great potential to be applied in end‐use products. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45082.

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Section: Introductionmentioning

confidence: 99%

Structural, mechanical, and thermal properties of 3D printed L‐CNC/acrylonitrile butadiene styrene nanocomposites

Feng

Yang

Rostom³

et al. 2017

J of Applied Polymer Sci

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“…Additionally, most of hypotheses or theoretical simulations were not experimentally verified [5,6]. In this context, the in-situ observation of foaming phenomena drew significant attention amongst researchers [7][8][9][10]. Villamizar and Han [7] designed a rectangular visualization mold with transparent quartz walls to investigate the bubbles' dynamics in conventional structural FIM.…”

Section: Introductionmentioning

confidence: 99%

“…Villamizar and Han [7] designed a rectangular visualization mold with transparent quartz walls to investigate the bubbles' dynamics in conventional structural FIM. Mahmoodi et al [8] used a visualization setup in which one side of the mold cavity was replaced with a multi-layer glass block in the moving part of the mold. They conducted fullshot FIM experiments using polystyrene (PS)/carbon dioxide (CO 2 ) system to visualize cell growth and [10] extended their study to compare the nucleation effectiveness of nitrogen (N 2 ) with that of CO 2 .…”

Section: Introductionmentioning

confidence: 99%

A new insight into foaming mechanisms in injection molding via a novel visualization mold

Shaayegan¹,

Mark²,

Tabatabaei³

et al. 2016

Express Polym. Lett.

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Abstract. The complex mechanisms of bubble nucleation and dynamics in foam injection molding have not been uncovered despite many previous efforts due to the non-steady stop-and-flow nature of injection molding and the non-uniform temperature and pressure distributions in the mold. To this end, a new visualization mold was designed and manufactured for the direct observation of bubble nucleation and growth/collapse in foam injection molding. A reflective prism was incorporated into the stationary part of the injection mold with which the nucleation and growth behaviors of bubbles were successfully observed. The mechanisms of bubble nucleation in low-and high-pressure foam injection molding, with and without the application of gas-counter pressure, was investigated. We identified how the inherently non-uniform cell structure is developed in low-pressure foam injection molding with gate-nucleated bubbles, and when and how cell nucleation occurs in high-pressure foam injection molding with a more uniform pressure drop.

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“…Villamizar and Han visualized the formation and growth of cells in conventional low‐pressure FIM, and evaluated the effects of processing parameters on the cellular structure . Mahmoodi et al studied the growth/collapse behavior of nucleated cells in a non‐isothermal high‐pressure FIM process using mold visualization . Lee et al studied structural evolution in a low‐pressure FIM process, using cavity pressure profiles, and proposed strategies that resulted in a faster pressure drop over the gate .…”

Section: Introductionmentioning

confidence: 99%

Identification of cell‐nucleation mechanism in foam injection molding with gas‐counter pressure via mold visualization

et al. 2016

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The mechanisms of cell nucleation and growth are investigated in foam injection molding (FIM) using gas-counter pressure (GCP). An in-situ mold visualization technique is employed. The application of GCP suppresses cell nucleation, and prevents the blowing agent from escaping during mold-filling. The inherent structural heterogeneity in the regular FIM can be improved because of the uniform cavity pressure when employing GCP. The cavity pressure profiles show much faster pressure-drop rates using GCP, because the single-phase polymer/gas mixture has a lower compressibility than the two-phase polymer/bubble mixture. Therefore, both the cell nucleation and growth rates are significantly increased through a higher pressure-drop rate on the removal of the GCP. The effect of GCP magnitude on the cell morphology is explored. When the GCP is lower than the solubility pressure, bimodal foaming occurs. As the GCP increases above the solubility pressure, the cell density increases because of the higher pressure-drop rate. Figure 14. Formation of a bimodal structure as a result of an insufficient GCP of 2.30 MPa (injection speed: 35 cm 3 s 21 ; CO 2 : 1%; T melt 5 230 C).

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Visualization of bubble dynamics in foam injection molding

Cited by 24 publications

References 18 publications

Structural, mechanical, and thermal properties of 3D printed L‐CNC/acrylonitrile butadiene styrene nanocomposites

Structural, mechanical, and thermal properties of 3D printed L‐CNC/acrylonitrile butadiene styrene nanocomposites

A new insight into foaming mechanisms in injection molding via a novel visualization mold

Identification of cell‐nucleation mechanism in foam injection molding with gas‐counter pressure via mold visualization

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