Evaluation of heat transfer at the cavity-polymer interface in microinjection moulding based on experimental and simulation study

Babenko, Maksims; Sweeney, J.; Petkov, Petko Vladev; Lacan, Franck; Bigot, Samuel; Whiteside, Ben

doi:10.1016/j.applthermaleng.2017.11.022

Cited by 30 publications

(31 citation statements)

References 15 publications

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“…(weight) of carbon black (CB) pigment [31], which makes it opaque in the infrared region where the thermo-camera has the highest sensitivity (i.e. 3-5 µm).…”

Section: Thermal Imagingmentioning

confidence: 99%

Comparison of crystallization characteristics and mechanical properties of polypropylene processed by ultrasound and conventional micro-injection molding

Masato

Babenko

Shriky

et al. 2018

Int J Adv Manuf Technol

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Ultrasound injection molding has emerged as an alternative production route for the manufacturing of micro scale polymeric components, where it offers significant benefits over the conventional micro injection molding process. In this work, the effects of ultrasound melting on the mechanical and morphological properties of micro polypropylene parts were characterized. The ultrasound injection molding process was experimentally compared to the conventional micro injection molding process using a novel mold, which allows mounting on both machines and visualization of the melt flow for both molding processes. Direct measurements of the flow front speed and temperature distributions were performed using both conventional and thermal high-speed imaging techniques. The manufacturing of micro tensile specimens allowed the comparison of the mechanical properties of the parts obtained with the different processes. The results indicated that the ultrasound injection molding process could be an efficient alternative to the conventional process.

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“…(weight) of carbon black (CB) pigment [31], which makes it opaque in the infrared region where the thermo-camera has the highest sensitivity (i.e. 3-5 µm).…”

Section: Thermal Imagingmentioning

confidence: 99%

Comparison of crystallization characteristics and mechanical properties of polypropylene processed by ultrasound and conventional micro-injection molding

Masato

Babenko

Shriky

et al. 2018

Int J Adv Manuf Technol

Self Cite

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“…They were done using both types of solver that are proposed by Moldflow code. [18] For the conduct solver the three h tc values were used, whereas for the flow solver only two values of h tc were used (7700 [18] and 30 000 W/m 2 . K [9] ).…”

Section: Meshing and Simulation Input Parametersmentioning

confidence: 99%

“…These values are questionable. Rytka et al [10] showed that an h tc value close to 30 000 W/m 2 .K is better while Babenko et al [18] established, by using innsitu measures from a high speed thermal camera, that an h tc value of 7700 W/m 2 .K allows one to be closer (about 0.2 K) to the actual flow front temperature of the studied polypropylene (PP) and polystyrene (PS). Babenko et al concludes his paper by showing the importance of this h tc in the microinjection and that the default value used by the Moldflow software is not suitable (25 K deviation from the measured temperatures).…”

Section: Introductionmentioning

confidence: 99%

Submillimeter features on injected acrylonitrile butadiene styrene parts: Visualization of the flow and numerical simulation

Brulez

Boschard

Larochette

et al. 2020

Polymer Engineering & Sci

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Numerical simulation of classical dimension parts with micrometric textures on their surface is still difficult to master. The limit condition of the calculations, and in particular, the implemented values, characteristics of the polymer and thermal exchanges (polymer/mold) strongly impact the results. Starting from a model with a 370 μm wide rib, by means of a numerical simulation, a study was done on the evolution of the material flow front velocities and the flow lengths in both the macroscopic part and the microgroove. This innovative visualization mold design was used to determine the velocities from an experimental perspective and to discuss the calculation conditions. On the one hand, there are significant differences regarding the choice of the no flow temperature (~ 40 K) used in the calculation code, the analytical heat transfer equation as well as the experimental results. On the other hand, according to the no flow temperature, it may be necessary to consider, during the filling phase, a perfect mold/polymer thermal contact in the groove. Depending in particular on the injection velocity and the geometry of the micro textures, a characteristic time can be determined which defines an optimal operating point for the topographic texture of the part.

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“…[21] Rytka et al [16] emphasized the strong link between texture replication quality and the injection velocity, whereas P H was not observed to have any influence at relatively high injection velocities. [20,22] Few authors have exhaustively listed the influence of each parameter on the quality of replication. [23,24] This complicates the process of optimization based on compromises among different parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Recent works on the study and the modeling of the thermal exchanges between the mold and the polymer have eliminated some of ambiguities [25] in particular, the work of Babenko et al which uses an IR camera to identify the thermal fields in situ in the mold. [22] However, the dependence of the quality of reproduction of the part's textures as a function of the cavity pressurizing velocity of the polymer is less well studied. This pressurizing velocity depends on the process parameters (injection velocity, mold temperature, melt temperature, etc.…”

Section: Introductionmentioning

confidence: 99%

Injection of a microtextured polymer part surface: Influence of experimental parameters on the replication rate

Brulez

Boschard

Larochette

et al. 2020

Polymer Engineering & Sci

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Injection manufacturing makes it possible to functionalize the surfaces of microtextured plastic parts without resorting to expensive post‐treatments. An instrumented mold was developed and microtextures were etched in the cavity with a femtosecond laser. A setting methodology only following in situ parameters, especially cavity pressurizing velocity was used to complete process control. The quality of the replication was quantified by the ratio, R, of microtexture part height replication over etched texture depth in the cavity. Different setting parameters such as injection velocity, Vf, mold temperature, TMo, and holding pressure, PHMax, were investigated on two different injection molding machine. A statistical analysis enabled a validation of the protocol while showing that the influence of the injection molding machine is nonsignificant. Furthermore, injection velocity appeared as a key parameter, it acts at the same time on the thermal aspect of the flow front, frozen‐layer fraction creation, but more importantly on the polymer's viscosity. An injection velocity threshold where above, mold temperature and holding pressure become secondary for better quality replication. This allowed as well to establish an empiric expression which makes it possible to calculate a pattern quality replication ratio, R, according to different parameters (Vf, TMo, PHMax).

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Evaluation of heat transfer at the cavity-polymer interface in microinjection moulding based on experimental and simulation study

Cited by 30 publications

References 15 publications

Comparison of crystallization characteristics and mechanical properties of polypropylene processed by ultrasound and conventional micro-injection molding

Comparison of crystallization characteristics and mechanical properties of polypropylene processed by ultrasound and conventional micro-injection molding

Submillimeter features on injected acrylonitrile butadiene styrene parts: Visualization of the flow and numerical simulation

Injection of a microtextured polymer part surface: Influence of experimental parameters on the replication rate

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