Rapid control of mold temperature during injection molding process

Liparoti, Sara; Hunag, Tsang Min; Sorrentino, Andrea; Titomanlio, G.; Çakmak, Mükerrem

doi:10.1063/1.4918490

Cited by 6 publications

(8 citation statements)

References 10 publications

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“…To obtain a smooth surface, the specimens were microtomed by a Leica microtome. The specimens were then chemically etched following the procedure reported by White and Bassett [53] and previously adopted on similar iPP samples [37,38,42]. In order to determine the effect of the etching procedure on the mechanical results, the samples were etched for different times.…”

Section: Sample Preparationmentioning

confidence: 99%

“…In this paper, we intend to demonstrate the applicability of HarmoniX AFM technique to the characterization of molded polymer samples with complex, nonuniform morphologies [37][38][39][40][41][42], which could influence the mechanical properties of the final object [28,43,44]. To accomplish this objective, a series of HarmoniX tests have been performed on selected polypropylene molded samples.…”

Section: Introductionmentioning

confidence: 99%

“…To accomplish this objective, a series of HarmoniX tests have been performed on selected polypropylene molded samples. These samples have been chosen to highlight the sensitivity of this technique to the variations in morphologies normally found in molded thermoplastic samples [37,38,41,42,45]. HarmoniX tests have been conducted with different scan sizes and resolutions on samples prepared in different ways (i.e., etching procedures), with the objective of studying the relative influence of the preparation methods on the obtained results.…”

Section: Introductionmentioning

confidence: 99%

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Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Liparoti

Sorrentino

Speranza

2017

International Journal of Polymer Science

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This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM) technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.

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Section: Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Liparoti

Sorrentino

Speranza

2017

International Journal of Polymer Science

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“…The heating device is composed by a conductive layer, that is electrically insulated from the mold by two polyimide layers, and a steel layer (100 micron thickness) covers that device and comes in contact with the polymer [5].…”

Section: Materials and Molding Experimentsmentioning

confidence: 99%

“…On the other hand, setting a high mold temperature addition cooling time is required. Previous works [4][5][6] demonstrated that it is possible to obtain a fast temperature evolution on the mold surface in order to have a high mold temperature only during the filling and a fast cooling soon after. Temperature evolution on mold surface has a significant effect on the morphology distribution of the final object [7,8].…”

Section: Introductionmentioning

confidence: 99%

Fast temperature evolution on the mold surface: Analysis and simulation

Liparoti¹,

Speranza²,

Pantani³

et al. 2016

AIP Conference Proceedings

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Effect of fast mold surface temperature evolution on iPP part morphology gradients AIP Conference Proceedings 1713, 170001 (2016) Abstract. Injection molding is one of the most widespread processes in the polymeric manufacturing field, because it allows to have a good reproducibility of the molded objects in a very short cycle time. The possibility to control mold temperature during the process, so as to have high temperature during filling and low temperature during cooling, is considered very attractive for several reasons. To this purpose, fast mold surface heating is proposed in this paper. A mold temperature rise of about 100°C in 1-2 seconds was obtained by a thin electric heater layered on the mold surface. A fast cooling phase and, as a consequence, a fast cycle time is not lost because the heating layer thickness is small. Injection molding tests were performed with a very accurately characterized iPP as far as rheology, quiescent crystallization, effect of flow on nucleation and spherulitic growth rates and spherulitic/fibrillar transition. A series of tests with different heating powers (steady mold wall temperatures) held constant from about 2s before the contact of the polymer on the cavity surface to the end of filling are considered in this work. The effect of the heating powers on the skin, the shear layer and spherulitic layer thicknesses is identified and discussed. A simple model of the morphology evolution during the process, accounting of the effect of molecular stretch on nucleation density and growth rate of the isotactic polypropylene (iPP) adopted for the experiments, was adopted to describe the experiments The model predictions for final morphologies distributions reproduce main characteristics of the experimental results.

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Flexible Poly(Amide‐Imide)‐Carbon Black Based Microheater with High‐Temperature Capability and an Extremely Low Temperature Coefficient

Liparoti

Landi

Sorrentino

et al. 2016

Adv Elect Materials

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heating element comprises a conductive polymer material. Polymer loaded with conducting fi llers such as carbon-based materials and metal fi bers have been extensively investigated owing to their lightweight and good processability. [1][2][3][4] They are ideal for many smart applications, such as patternable microheaters, temperature sensors, thermoelectric devices, water heaters, and fl exible deicing units. [5][6][7] However, up to now low values of dielectric strength, dimensional stability, thermal insulation, electrical power density, and maximum operating temperature have limited their applications in fl exible heater manufacturing. [ 8,9 ] So far, metal-based microheaters on fl exible foils are the dominant approach in the fi eld. The substitution of conventional microheaters with polymer-based microheaters can expand their applications to extreme environments or for cases, where space and weight allowances are limited. Several approaches related to their formulation and processing have been proposed to overcome the limitations of purely polymer-based solutions. Nanosized particles have received great attention due to their electrical cycle stability and their potential in processing thin fi lms with uniform morphology. In this case, a number of new problems, such as signifi cant particle agglomeration, high interface fraction, and porosity in polymer matrices need to be resolved during nanocomposite production. Probably, the most important issue is the fi ller distribution within the matrix, which depends strongly on the right combination of processing conditions (pressure, temperature, humidity, mixing, etc.), formulation (fi ller content, properties of the matrix), and particle-matrix interactions. [ 10 ] Controlling the impact of all these parameters allows to fi nd the right balance between dispersion and aggregation phenomena in order to prevent either the formation of microagglomerates or of conductive pathway breakage. Generally, it is preferable to decrease the fi ller content value at which the composite becomes conductive (percolation threshold). This is generally achieved by partial segregation of the fi ller or by using conductive nanometric fi llers with high aspect ratio. Among these, nanocarbon materials such as carbon nanotubes (CNTs), graphene, and carbon nanofi bers are used to obtain highly conductive polymer composites with a very low Flexible poly(amide-imide)-carbon black (PAI-CB) composite fi lms, to be applied as high performance microheater foil, have been prepared with a solution/casting technique. The CB dispersion has been carefully controlled in order to improve the thermal and electrical properties of the resulting composites. Morphology and structure of the PAI-CB composite fi lms have been characterized by optical microscopy, atomic force microscopy and FTIR spectroscopy. The effect of the CB dispersion and its interaction with the polymer chains on the thermal and mechanical properties of the composite fi lms have been investigated by using differential scanning calorimetr...

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Rapid control of mold temperature during injection molding process

Cited by 6 publications

References 10 publications

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

Fast temperature evolution on the mold surface: Analysis and simulation

Flexible Poly(Amide‐Imide)‐Carbon Black Based Microheater with High‐Temperature Capability and an Extremely Low Temperature Coefficient

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