Microcellular Foam Injection Molding Process

Hu, Guanghong

doi:10.5772/34513

Cited by 18 publications

(16 citation statements)

References 18 publications

(12 reference statements)

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“…Volpe et al [70] concluded that longer flow paths and faster cycle times can be obtained compared to usual injection molding due to the plasticization effect induced by the added supercritical blowing agent (i.e., the glass transition and melting temperature are decreased and the melt viscosity is reduced). Guanghong et al [135] reviewed microcellular foams having uniform cell diameters of 1 to 100 µm, and Xu et al [133] reviewed cell densities of 10 5 to 10 9 cells per cubic centimeter for foams produced by this technique.…”

Section: Foam Injection Moldingmentioning

confidence: 99%

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

et al. 2020

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Polylactic acid (PLA) is a well-known and commercially available biopolymer that can be produced from different sources. Its different characteristics generated a great deal of interest in various industrial fields. Besides, its use as a polymer matrix for foam production has increased in recent years. With the rise of technologies that seek to reduce the negative environmental impact of processes, chemical foaming agents are being substituted by physical agents, primarily supercritical fluids (SCFs). Currently, the mass production of low-density PLA foams with a uniform cell morphology using SCFs as blowing agents is a challenge. This is mainly due to the low melt strength of PLA and its slow crystallization kinetics. Among the different options to improve the PLA characteristics, compounding it with different types of fillers has great potential. This strategy does not only have foaming advantages, but can also improve the performances of the final composites, regardless of the implemented foaming process, i.e., batch, injection molding, and extrusion. In addition, the operating conditions and the characteristics of the fillers, such as their size, shape factor, and surface chemistry, play an important role in the final foam morphology. This article proposes a critical review on the different SCF-assisted processes and effects of operating conditions and fillers on foaming of PLA composites.

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Section: Foam Injection Moldingmentioning

confidence: 99%

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

et al. 2020

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“…Swirl marks and silver streaks are generated because of gas trapped in the mold, as the melt flow front pushes cells to the surface cavity, where they are stretched and frozen [95]. Other typical surface defects are surface blistering, post-blow and large surface roughness [96]. Some progress in improving surface quality has been made and different solutions based on mold technologies have been successfully applied.…”

Section: Foam Stabilization and Shaping In The Moldmentioning

confidence: 99%

“…Finally, the cooling time is also shortened, because of the lower amount of material to cool down and also because cell nucleation and growth are endothermic processes, contributing to cooling down the part faster. As a result, the overall cycle time of the foaming processes is reduced from 20% up to 50% as compared to conventional injection molding[96] (Figure 2.11).…”

mentioning

confidence: 99%

Characterization of microcellular plastics for weight reduction in automotive interior parts

Monterde¹

2017

Kunststoffe Im Automobilbau 2017

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“…6,7 The SFC content determines the number of nuclei in the melt. 8 Then, the mould filling causes a pressure drop in the melt leading to the gas separation and the cell formation in the part. The cell growth is influenced by the melt viscosity and the cooling rate in the mould.…”

Section: Introductionmentioning

confidence: 99%

Injection-moulding of nitrogen-foamed bio-based microcellular poly(butylene succinate): Processing conditions/foam structure/flexural properties relationship

Ykhlef

Lafranche

2020

Polymers from Renewable Resources

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This paper aims to identify the main processing parameters that optimize as well the microcellular structure (cell size, cell density) of nitrogen (N2) foamed injection-moulded poly(butylene succinate) (PBS) as the resultant flexural properties of the part. The part beam geometry was designed so as to reproduce some geometrical shapes (e.g. thickness change, ribs, bosses or holes) occurring on most of industrial parts. A Taguchi L9 design of experiments (DOE) has been first used to quantify the effects of processing conditions on microcellular structure and mechanical performances. Among the processing parameters, the melt temperature, gas content, injection volumetric flow rate and back pressure were chosen for the DOE due to their level of influence on gas dissolution and nucleation phases. An analysis of variance (ANOVA) showed that the microcellular structure depended mainly on nitrogen content and, to a lesser extent, on back pressure representation of gas pressure saturation in the PBS/N2 system during the feeding stage. The resultant specific flexural properties were controlled by the skin/core ratio as well as the finesse of foam structure (cell sizes, cell density) but a 15% loss in specific performances was noted compared with the unfoamed part. The microcellular structure/mechanical performances could be thus established from the microstructure analysis. In a second step, the foamed microcellular structure has been improved by introduction of micro-talc in the PBS acting as cell nucleating agent (heterogeneous nucleation). A significant increase in cell density and cell reduction (40%) were observed.

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Microcellular Foam Injection Molding Process

Cited by 18 publications

References 18 publications

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

Characterization of microcellular plastics for weight reduction in automotive interior parts

Injection-moulding of nitrogen-foamed bio-based microcellular poly(butylene succinate): Processing conditions/foam structure/flexural properties relationship

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