Flow behaviour of rubber in capillary and injection moulding dies

Mitsoulis, Evan; Battisti, Markus; Neunhäuserer, Andreas; Perko, Leonhard; Friesenbichler, Walter; Ansari, Mahmoud; Hatzikiriakos, Savvas G.

doi:10.1080/14658011.2017.1298207

Cited by 15 publications

(7 citation statements)

References 30 publications

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“…The critical shear stress and occurred wall slip behavior will be affected by a variety of factors in molding process, for instance, the wall slip rate increases with the increase of melt temperature and speed, the critical shear stress decreases with the increase of molecular weight, the size and structure of the micro cavity also affects the slip behavior . The wall slip behavior of the melt in micro cavity closely relates to the molding quality of micro polymer parts because of the complex and non‐negligible influence of the wall slip on the flow field of the melt . The influence includes significantly reducing the wall shear stress and the melt apparent viscosity, decreasing the velocity gradient, improving the uniformity of flow rate distribution and viscosity distribution, thus promoting the mold filling in micro cavity, or further transforming the flow field into a piston flow .…”

Section: Introductionmentioning

confidence: 99%

Wall Slip of Linear Polymer Melts During Ultrasonic‐assisted Micro‐injection Molding

Gao

Qiu

Ouyang

et al. 2018

Polymer Engineering & Sci

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The wall slip of linear polymer melts under ultrasonic vibration is investigated by correcting the slip mechanism, and melt flow behaviors in ultrasonic‐assisted micro‐injection molding (UμIM) method are discussed. Based on the effect mechanism of ultrasonic vibration on the melt, theoretical models of the critical shear stresses for the onset of weak and strong wall slip during UμIM are established, and the change in rheological properties due to the onset of wall slip under ultrasonic vibration is experimental investigated by a built measurement system. The results show that the onset of weak and strong wall slip of the melt in micro cavity are promoted by ultrasonic vibration, which agree with the built theoretical models, and the melt filling capability in micro cavity is enhanced by reducing apparent viscosity and releasing shear stress of the polymer melt, which improves the molding quality of micro polymer parts via UμIM method. POLYM. ENG. SCI., 59:E7–E13, 2019. © 2018 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Wall Slip of Linear Polymer Melts During Ultrasonic‐assisted Micro‐injection Molding

Gao

Qiu

Ouyang

et al. 2018

Polymer Engineering & Sci

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“…Furthermore, another mechanism should be considered in this case. With the increase in testing temperature, the rheology of the rubber material (the counterbody and the transferred rubber layers) is expected to decrease [ 40 ]. Therefore, it will be easier to shear, resulting in lower CoF.…”

Section: Resultsmentioning

confidence: 99%

On the Microstructural, Mechanical and Tribological Properties of Mo-Se-C Coatings and Their Potential for Friction Reduction against Rubber

et al. 2021

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Friction and wear contribute to high energetic losses that reduce the efficiency of mechanical systems. However, carbon alloyed transition metal dichalcogenide (TMD-C) coatings possess low friction coefficients in diverse environments and can self-adapt to various sliding conditions. Hence, in this investigation, a semi-industrial magnetron sputtering device, operated in direct current mode (DC), is utilized to deposit several molybdenum-selenium-carbon (Mo-Se-C) coatings with a carbon content up to 60 atomic % (at. %). Then, the carbon content influence on the final properties of the films is analysed using several structural, mechanical and tribological characterization techniques. With an increasing carbon content in the Mo-Se-C films, lower Se/Mo ratio, porosity and roughness appeared, while the hardness and compactness increased. Pin-on-disk (POD) experiments performed in humid air disclosed that the Mo-Se-C vs. nitrile butadiene rubber (NBR) friction is higher than Mo-Se-C vs. steel friction, and the coefficient of friction (CoF) is higher at 25 °C than at 200 °C, for both steel and NBR countersurfaces. In terms of wear, the Mo-Se-C coatings with 51 at. % C showed the lowest specific wear rates of all carbon content films when sliding against steel. The study shows the potential of TMD-based coatings for friction and wear reduction sliding against rubber.

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“…The molding quality of micro-polymer parts is largely controlled by the melt flow field in the micro-cavity, in which the influence of wall slip is complex and cannot be ignored [ 98 ]. The influence includes significantly reducing the wall shear stress and the melt apparent viscosity, reducing the velocity gradient, improving the uniformity of flow rate distribution and viscosity distribution, and thus promoting the mold filling in micro-cavity, or further transforming the flow field into a piston flow, which is good for filling [ 99 , 100 ].…”

Section: Ultrasound-assisted Micro-injection Moldingmentioning

confidence: 99%

Tuning Power Ultrasound for Enhanced Performance of Thermoplastic Micro-Injection Molding: Principles, Methods, and Performances

Zhao

Qiang

et al. 2021

Polymers

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With the wide application of Micro-Electro-Mechanical Systems (MEMSs), especially the rapid development of wearable flexible electronics technology, the efficient production of micro-parts with thermoplastic polymers will be the core technology of the harvesting market. However, it is significantly restrained by the limitations of the traditional micro-injection-molding (MIM) process, such as replication fidelity, material utilization, and energy consumption. Currently, the increasing investigation has been focused on the ultrasonic-assisted micro-injection molding (UAMIM) and ultrasonic plasticization micro-injection molding (UPMIM), which has the advantages of new plasticization principle, high replication fidelity, and cost-effectiveness. The aim of this review is to present the latest research activities on the action mechanism of power ultrasound in various polymer micro-molding processes. At the beginning of this review, the physical changes, chemical changes, and morphological evolution mechanism of various thermoplastic polymers under different application modes of ultrasonic energy field are introduced. Subsequently, the process principles, characteristics, and latest developments of UAMIM and UPMIM are scientifically summarized. Particularly, some representative performance advantages of different polymers based on ultrasonic plasticization are further exemplified with a deeper understanding of polymer–MIM relationships. Finally, the challenges and opportunities of power ultrasound in MIM are prospected, such as the mechanism understanding and commercial application.

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Flow behaviour of rubber in capillary and injection moulding dies

Cited by 15 publications

References 30 publications

Wall Slip of Linear Polymer Melts During Ultrasonic‐assisted Micro‐injection Molding

Wall Slip of Linear Polymer Melts During Ultrasonic‐assisted Micro‐injection Molding

On the Microstructural, Mechanical and Tribological Properties of Mo-Se-C Coatings and Their Potential for Friction Reduction against Rubber

Tuning Power Ultrasound for Enhanced Performance of Thermoplastic Micro-Injection Molding: Principles, Methods, and Performances

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