Micro injection molding processing of UHMWPE using ultrasonic vibration energy

Sánchez-Sánchez, Xavier; Hernández-Avila, Marcelo; Elizalde, Luis E.; Martínez, Óscar Sanjuán; Ferrer, I.; Elı́as-Zúñiga, Alex

doi:10.1016/j.matdes.2017.06.055

Cited by 55 publications

(38 citation statements)

References 28 publications

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“…Some of the major polymers used in manufacturing polymeric microparts include poly(methyl methacrylate), polyethylene, polyoxymethylene (POM), poly(lactic acid) (PLA), liquid crystal polymers, polypropylene, and so forth. [1][2][3][4] Accordingly, several microprocessing technologies, such as microinjection molding (μIM), hot embossing, thermoforming, injection-compression molding, and ultrasonic molding, 5,6 have been developed to satisfy ever-increasing demands of miniature products from the above industrial sectors. Among the above listed processing methods, μIM is recurrently adopted for largescale production, thanks to its short cycle times and suitability of producing microparts at a relatively low-cost per part.…”

Section: Introductionmentioning

confidence: 99%

Microinjection molding of polyoxymethylene/multiwalled carbon nanotubes composites with different matrix viscosities

Zhou

Xue

Mei

et al. 2020

J of Applied Polymer Sci

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This study features the effect of matrix viscosity on the properties of carbon nanotubes reinforced polyoxymethylene (POM/CNT) microparts, which were obtained via melt blending and subsequent microinjection molding (μIM) processes, under a defined set of processing conditions. Results of compression molding and μIM were compared to assess the influence of processing methods (i.e., thermomechanical history) on the electrical and thermal conductivities, melting and crystallization behavior as well as the thermal degradation resistance of POM/CNT composites. Filler orientation in POM/CNT microparts was evaluated using Raman spectral analysis. The electrical conductivity measurements revealed that matrix viscosity plays a significant role in determining the distribution of CNT. Also, the extreme shearing conditions that prevail in μIM are unfavorable for the construction of random conductive pathways within the micromoldings, as corroborated by transmission electron microscopy. Although the thermal degradation resistance of both POM/CNT composites and corresponding microparts deteriorated with increasing filler concentration, samples prepared with higher matrix viscosity showed higher thermal stability when compared with lower matrix viscosity counterparts. This study provides valuable insights into fabricating multifunctional microparts for potential industrial applications in replacement of metallic components for precision electronic instruments.

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Section: Introductionmentioning

confidence: 99%

Microinjection molding of polyoxymethylene/multiwalled carbon nanotubes composites with different matrix viscosities

Zhou

Xue

Mei

et al. 2020

J of Applied Polymer Sci

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“…Ultrasonic processing technology, as a novel molding processing technology, has been widely used in recent years for the injection molding, extrusion molding, and compression molding of polymers [9,10]. Despite different ways of applying ultrasonic energy, studies have found that ultrasounds can affect the microstructure filling performance [11], change the material properties [12], affect the extrusion swelling [13], improve the weld line strength of the plastic parts [14], and reduce the interface friction during ejection [15]. However, current studies are mainly based on experiments.…”

Section: Introductionmentioning

confidence: 99%

Micro-Ultrasonic Viscosity Model Based on Ultrasonic-Assisted Vibration Micro-Injection for High-Flow Length Ratio Parts

Lou

Xiong

2020

Polymers

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A micro-ultrasonic (MU) viscosity model based on ultrasonic-assisted vibration micro-injection for high- flow length ratio polymer parts was established. This model considered the effects of ultrasonic energy and the characteristic microdimension. Ultrasonic energy parameters (such as the ultrasonic amplitude, frequency, and ultrasound velocity), the characteristic microdimension, and the molecular chain length (MCL) were introduced into the MU viscosity model. An ultrasonic micro-injection experimental platform was built on an injection molding machine. Polypropylene (PP) filling experiments were carried out using microgrooves with different flow length ratios (depth-to-width ratios of 3:1, 5:1, and 10:1). The validity and accuracy of the MU viscosity model were examined through a filling experiment with polypropylene (PP) microgroove injection molding and by a flow pressure difference experiment with polystyrene (PS). The results showed that the MU viscosity model was in better agreement with the experimental results compared to other models. The maximum error of the MU model was 4.9%. Ultrasound-assisted vibration had great effects on the filling capacity for microgrooves with high flow length ratios (depth-to-width ratios greater than 5:1). The filling capacity increased as the ultrasonic amplitude increased.

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“…The molecular degradation could be alleviated, even avoided by appropriate parameter combinations. Grabalosa et al [8] and Sanchez et al [9] concluded that the filling rate could be ameliorated by increasing ultrasonic action time, plasticizing time and plasticizing pressure. Bingyan Jiang et al [10] studied the effects of ultrasound and temperature on the fluidities of different polymers (PMMA, PP, PA66) under micro-scale.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Processing Parameters on the Shear Viscosity of Cyclic Olefin Copolymer Plasticized by Ultrasonic Vibration Energy

Qiang

et al. 2020

Polymers

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Shear viscosity of the cyclic olefin copolymer (COC) plasticized by ultrasonic vibration energy is characterized by high pressure capillary rheometer. Two different plasticization modes were adopted to prepare the samples with an in-house developed prototype machine. Single-factor experiments were conducted to investigate the effects of ultrasonic energy on the shear viscosity. The influences of the processing parameters and the plasticization modes were analyzed and compared. The results showed that the shear viscosity of COC was reduced under various parameter combinations, and demonstrated a significant difference in the lower shear rate range in comparison with the control samples; the results of gel permeation chromatography (GPC) showed that the COC’s number average molecular weight ( M ¯ n ) was decreased and the polymer dispersity index (PDI) was increased due to the plasticization by ultrasonic vibration energy. This could be further account for the decrease of the shear viscosity of COC. Moreover, the predominant ultrasonic parameter changed in different modes of plasticization according to the statistical analysis based on the Statistical Product and Service Solutions (SPSS) software.

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Micro injection molding processing of UHMWPE using ultrasonic vibration energy

Cited by 55 publications

References 28 publications

Microinjection molding of polyoxymethylene/multiwalled carbon nanotubes composites with different matrix viscosities

Microinjection molding of polyoxymethylene/multiwalled carbon nanotubes composites with different matrix viscosities

Micro-Ultrasonic Viscosity Model Based on Ultrasonic-Assisted Vibration Micro-Injection for High-Flow Length Ratio Parts

Effects of the Processing Parameters on the Shear Viscosity of Cyclic Olefin Copolymer Plasticized by Ultrasonic Vibration Energy

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