Modelling and Simulation of MuCell®: The Effect of Key Processing Parameters on Cell Size and Weight Reduction

Ding, Yifei; Vyas, Cian; Bakker, Otto Jan; Hinduja, S.; Bartolo, Paulo Jorge Da Silva

doi:10.3390/polym14194215

Cited by 8 publications

(10 citation statements)

References 43 publications

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“…Therefore, it can be concluded that in this case, the melt flow speed was significantly higher in the case of a smaller-thickness molding, which probably resulted in a reduction in the average size of the gas pores in the structure of these moldings. This is consistent with the effects described in papers [30,42,43]. For this reason, among others, the size of the pores in the 6 mm molding was lower than in the 8.4 mm moldings, which disturbed the linear relationship between the thickness of the molding and the size of the pores.…”

Section: X-ray Microtomography Analysissupporting

confidence: 91%

Structure Analysis and Its Correlation with Mechanical Properties of Microcellular Polyamide Composites Reinforced with Glass Fibers

Szewczykowski,

Sykutera,

Czyżewski

et al. 2023

Materials

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Thin-walled and thick-walled microcellular moldings were obtained by MuCell® technology with nitrogen as a supercritical fluid. 2 mm thick polyamide 6 (PA6) with 30% wt. glass fiber (GF) samples were cut from automotive industrial elements, while 4 mm, 6 mm, and 8.4 mm thick moldings of PA6.6 with 30% wt. GF were molded into a dumbbell shape. The internal structure was investigated by scanning electron microscopy (SEM) and X-ray computed microtomography (micro-CT) and compared by numerical simulations for microcellular moldings using Moldex3D® 2022 software. Young’s modulus, and tensile and impact strength were investigated. Weak mechanical properties of 2 mm thick samples and excellent results for thick-walled moldings were explained. SEM pictures, micro-CT, and simulation graphs revealed the tendency to decrease the cell size diameter together with increasing sample thickness from 2 mm up to 8.4 mm.

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Section: X-ray Microtomography Analysissupporting

confidence: 91%

Structure Analysis and Its Correlation with Mechanical Properties of Microcellular Polyamide Composites Reinforced with Glass Fibers

Szewczykowski,

Sykutera,

Czyżewski

et al. 2023

Materials

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“…Compared to POM gears, the micron‐sized cells formed in the microcellular injection molded PA66 gears were more abundant, as shown in Figure 4c. There was more gas dissolved into the polymer, 31 which accounted for the weight reduction difference between the foamed POM and foamed PA66. Moreover, most cells in PA66 gears had spherical shapes except for a proportion of ellipsoidal cells, which were deformed due to the flow of the melt during the filling process 26,32 .…”

Section: Resultsmentioning

confidence: 99%

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Feng

Zhan

et al. 2023

J of Applied Polymer Sci

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Polyformaldehyde (POM) and Polyamide 66 (PA66) are engineering plastics with excellent mechanical properties and thermal stability. Producing microcellular injection molded POM and PA66 parts with high dimensional accuracy would be beneficial to reduce material cost and product quality. In this research, foamed POM and PA66 gear parts were fabricated by using microcellular injection molding with supercritical nitrogen as the blowing agent. Compared to conventional injection molded parts (parts that foaming is not involved), the foamed POM and PA66 gear parts achieved 5% and 10% average weight reduction, respectively. The foamed parts displayed a lower shrinkage ratio when compared to the solid counterparts, which was attributed to the cell expansion that offset part of the inward shrinkage stress. Moreover, POM gear parts with a higher crystallinity degree presented more serious shrinkage ratio compared to the PA66 gear parts, which contributed to the denser polymer molecular chains arrangement. The shrinkage ratio in both directions of PA66 foamed gear parts depended on the injection volume, and the lowest shrinkage ratio of 0.043‰ was obtained at the injection volume of 74 mm, when the polymer reached the maximum foaming ratio. The findings from this study could provide practical guidance for preparing microcellular injection molded products with high dimensional accuracy.

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“…Point 1 is located at the center of the sample just below the injection gate. Based on a previous simulation on the cell distribution [56], Points 2 to 5 are located in Z direction between the center and main area, and the distance between them and Point 1 is 33 mm. Since the temperature results in the horizontal direction of the sample cross-section exhibit little differences, Points 6 to 10 are selected near the sample side, and the distance between Point 6 and Point 1 is 75 mm.…”

Section: Part Design and Materialsmentioning

confidence: 99%

Investigation on the Crystallization Process of Microcellular Injection Moulded Parts and the Influences of Parameters on the Crystallization by Simulation

Ding,

Yang,

Bakker

et al. 2023

Preprint

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Crystallization, as a physical transformation process, plays an important role on the final properties of a plastic part. Similar to other injection moulding processes, injection and cooling conditions in microcellular injection moulding (e.g. MuCell® process) determine the phase change transformation of the material (molten to solid) and consequently, nucleation, crystal growth and crystallinity. The crystallization process of microcellular injection moulded parts has been mainly investigated using laborious and time-consuming experimental characterization techniques, but no studies reported the use of numerical methods to estimate the crystallization process. This paper presents a mathematical model successfully used to simulate the crystallization process of microcellular injection moulded parts. Microcellular injection moulding was simulated using Moldex 3D, and the crystallization process was investigated using the Hoffman nucleation theory for the crystal nucleation rate, the Lauritzen-Hoffman growth theory for the crystal growth rate, and the Avrami model to calculate the relative crystallinity. Numerical simulations allowed to investigate the effect of key processing parameters (melt temperature, mould temperature, flow rate, gas dosage amount and shot volume) on the crystallization process. Moreover, the numerical model was validated considering published experimental data.

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Modelling and Simulation of MuCell®: The Effect of Key Processing Parameters on Cell Size and Weight Reduction

Cited by 8 publications

References 43 publications

Structure Analysis and Its Correlation with Mechanical Properties of Microcellular Polyamide Composites Reinforced with Glass Fibers

Structure Analysis and Its Correlation with Mechanical Properties of Microcellular Polyamide Composites Reinforced with Glass Fibers

Microcellular injection molding of foamed engineering plastic parts with high dimensional accuracy

Investigation on the Crystallization Process of Microcellular Injection Moulded Parts and the Influences of Parameters on the Crystallization by Simulation

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