A Review on Microcellular Injection Moulding

Ding, Yifei; Hassan, Mohamed H.; Bakker, Otto Jan; Hinduja, S.; Bartolo, Paulo Jorge Da Silva

doi:10.3390/ma14154209

Cited by 24 publications

(17 citation statements)

References 96 publications

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“…Autodesk Moldflow Insight (AMI) 2021 software, US, [ 34 , 35 ] was used for the simulation of small-module plastic gear micro-injection molding. For small-module gears, the polymer filling process is extremely short, and the process cannot be observed visually, so it is difficult to characterize experimentally.…”

Section: Methodsmentioning

confidence: 99%

An Effective Shrinkage Control Method for Tooth Profile Accuracy Improvement of Micro-Injection-Molded Small-Module Plastic Gears

et al. 2022

Polymers

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An effective method to control the non-linear shrinkage of micro-injection molded small-module plastic gears by combining multi-objective optimization with Moldflow simulation is proposed. The accuracy of the simulation model was verified in a micro-injection molding experiment using reference process parameters. The maximum shrinkage (Y1), volume shrinkage (Y2), addendum diameter shrinkage (Y3), and root circle diameter shrinkage (Y4) were utilized as optimization objectives to characterize the non-linear shrinkage of the studied gear. An analysis of the relationship between key process parameters and the optimization objectives was undertaken using a second-order response surface model (RSM-Quadratic). Finally, multi-objective optimization was carried out using the non-dominated sorting genetic algorithm-II (NSGA-II). The error rates for the key shrinkage dimensions were all below 2%. The simulation results showed that the gear shrinkage variables, Y1, Y2, Y3, and Y4, were reduced by 5.60%, 8.23%, 11.71%, and 11.39%, respectively. Moreover, the tooth profile inclination deviation (fHαT), the profile deviation (ffαT), and the total tooth profile deviation (FαT) were reduced by 47.57%, 23.43%, and 49.96%, respectively. Consequently, the proposed method has considerable potential for application in the high-precision and high-efficiency manufacture of small-module plastic gears.

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Section: Methodsmentioning

confidence: 99%

An Effective Shrinkage Control Method for Tooth Profile Accuracy Improvement of Micro-Injection-Molded Small-Module Plastic Gears

et al. 2022

Polymers

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“…This requires a process-oriented design of the molded part, the optimization of gating systems, and the setting of suitable speed profiles to achieve uniform filling of single and multiple cavities, cf. [34,35]. The injection molding process is fundamentally subject to considerable inhomogeneities and often involves thermal or rheological transient behavior.…”

Section: Basic Description Of the Injection Molding Processmentioning

confidence: 99%

Numerical simulation of the mold filling process and its experimental validation

Baum

Jasser

Stricker

et al. 2022

Int J Adv Manuf Technol

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The present study deals with the simulation of the filling process in injection molding using Ansys CFX and its experimental validation. For this purpose, the filling process of an exemplary mold is investigated numerically as well as experimentally at different time steps. For the numerical investigation, a suitable model is elaborated in Ansys CFX, which enables such a comparison. In particular, the representation of a suitable viscosity model for polymers is not common in Ansys CFX. Therefore, the Carreau-WLF viscosity model is adapted for the considered polymer Schulamind 66 SK 1000 and integrated into Ansys CFX. The contribution focuses on the comparison of the numerically calculated flow front contour and the respective filling levels of the melt from experiments. Furthermore, a detailed numerical analysis of temperature and viscosity profiles is included in order to illustrate the effect of shear-induced temperature changes and the interplay between the temperature field and the viscosity of the injected polymer. In conclusion, the numerical model nicely fits the experimental results despite some slight deviations in the early filling stages.

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“…In the early stages, CO 2 -blown cellular foams were produced by batch foaming and were primarily used in research and development . Later, semicontinuous and continuous processing techniques like microcellular injection and extrusion methods were developed to make lightweight foam components with multimaterials for mass production in industries for commercial applications like sofa cushions. , Eventually, the application of these polymeric foam is extended to the field of scaffold manufacturing, sensor, and electromagnetic shielding (EMI) …”

Section: Introductionmentioning

confidence: 99%

Rapid Carbon Dioxide Foaming of 3D Printed Thermoplastic Polyurethane Elastomers

Ponnan

Thirunavukkarasu

Laroui

et al. 2022

ACS Appl. Polym. Mater.

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Polymeric foam preparation using the carbon dioxide (CO2) foaming technique is fascinating. Until now, the CO2-based foaming process has been carried out for a long saturation time. Once it is possible to produce a polymeric foam in a low saturation time, it can enhance foam production. This study investigates the foaming behavior of 3D printed TPU samples with three different hardness values. The variation of infill density in 3D printed samples provides a macroporous range in the sample and creates a path for the gas molecules to reach the polymer. Such a gas flow path expands the foam processing technique to be carried out at low saturation time and pressure. The foaming process carried out here follows two steps: first, CO2 gas saturation in a high-pressure stainless-steel vessel; second, then hierarchical microporous generation by devising a thermodynamically unstable condition by placing the gas saturated sample in a hot water bath set up. The results showed that the increase in saturation time and pressure increases the expansion behavior of the foam samples, whereas an increase in infill density restricts the foam expansion behavior. The crystalline hard segment (HS) enhances the heterogeneous cell nucleation and reduces the shrinkage of the foam samples. The foam sample with low infill density showed low compression strength. It could be improved by filling the macroporous gap with hydrogel during printing. This hydrogel-packed low infill density foam showed an increased compression strength of 0.8 MPa at 80% strain than the neat foam sample (without hydrogel) 0.12 MPa at 80% strain, confirmed through the cyclic compression test. Hence, this 3D printing integrated subcritical solid-state foaming system offers unparalleled freedom to design and create foam and increase its production. The one-pot preparation of low-density higher compression strength foam using hydrogel makes this technique more feasible for high-end applications.

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A Review on Microcellular Injection Moulding

Cited by 24 publications

References 96 publications

An Effective Shrinkage Control Method for Tooth Profile Accuracy Improvement of Micro-Injection-Molded Small-Module Plastic Gears

An Effective Shrinkage Control Method for Tooth Profile Accuracy Improvement of Micro-Injection-Molded Small-Module Plastic Gears

Numerical simulation of the mold filling process and its experimental validation

Rapid Carbon Dioxide Foaming of 3D Printed Thermoplastic Polyurethane Elastomers

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