Manufacturing of polymer micro parts by ultrasonic plasticization and direct injection

Michaeli, Walter; Kamps, Thomas; Hopmann, Christian

doi:10.1007/s00542-011-1236-8

Cited by 67 publications

(48 citation statements)

References 3 publications

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“…The usIM process is characterized by the use an ultrasound horn for the melting of the polymer pellets [19]. The energetic ultrasound waves are exploited to cyclically heat and deform the polymer at ultrasound frequencies.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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“…And some representative samples plasticized by ultrasonic energy under two different modes are shown in Figure 5 and Figure 6 respectively. As shown in Table 5, all the parameter combinations for which ultrasound action time is set as 2 s fail to plasticize COC, mainly because the action time of ultrasound wave is too short to generate adequate heat for melting COC, and the heat is attributed to the combined contribution of frictional heating effects and viscoelastic heating effects [26,27]. COC could be melted by the remaining combinations; and as one certain parameter increases, such as amplitude, time or pressure, material degradation is inevitable.…”

Section: Preliminary Results Of Processing Windowmentioning

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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“…The ultrasonic vibration energy is introduced by Heat generation in polymer pellets under ultrasonic vibration is one of the critical issues due to its influence on the melting quality. Michaeli believes that the energy source of ultrasonic plasticization mainly comes from frictional heat and viscoelastic heat, similar to ultrasonic welding [18]. We studied the mechanism of frictional heat generation and viscoelastic heat generation [19][20][21][22] and found that the interfacial frictional heat determines the temperature distribution during the initial stage of ultrasonic plasticization.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Interfacial Friction Angle and Contact Area of Polymer Pellets during the Initial Stage of Ultrasonic Plasticization

et al. 2019

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Interfacial friction heating is one of the leading heat generation mechanisms during the initial stage of ultrasonic plasticization of polymer pellets, which has a significant influence on the subsequent viscoelastic heating according to our previous study. The interfacial friction angle and contact area of polymer pellets are critical boundary conditions for the analysis of interfacial frictional heating of polymer pellets. However, the duration of the interfacial friction heating is extremely short in ultrasonic plasticization, and the polymer pellets are randomly distributed in the cylindrical barrel, resulting in the characterization of the distribution of the interfacial friction angle and contact area to be a challenge. In this work, the interfacial friction angle of the polymer pellets in the partially plasticized samples of polymethyl methacrylate (PMMA), polypropylene (PP), and nylon66 (PA66) were characterized by a super-high magnification lens zoom 3D microscope. The influence of trigger pressure, plasticizing pressure, ultrasonic amplitude, and vibration time on the interfacial friction angle and the contact area of the polymer pellets were studied by a single factor experiment. The results show that the compaction degree of the plasticized samples could be enhanced by increasing the level of the process parameters. With the increasing parameter level, the proportion of interfacial friction angle in the range of 0–10° and 80–90° increased, while the proportion in the range of 30–60° decreased accordingly. The proportion of the contact area of the polymer pellets was increased up to 50% of the interfacial friction area which includes the upper, lower, and side area of the cylindrical plasticized sample.

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Manufacturing of polymer micro parts by ultrasonic plasticization and direct injection

Cited by 67 publications

References 3 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

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

Evolution of Interfacial Friction Angle and Contact Area of Polymer Pellets during the Initial Stage of Ultrasonic Plasticization

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