Optimization of Polymer Extrusion Die Based on Response Surface Method

Razeghiyadaki, Amin; Zhang, Dichuan; Wei, Dongming; Perveen, Asma

doi:10.3390/pr8091043

Cited by 14 publications

(12 citation statements)

References 16 publications

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“…The variations observed in the solid bed profile are in good agreement with previous single screw literature data, showing that increasing the volumetric flow rate results in an increase of the solid fraction at the same position of the screw length. These observations have been attributed to a shorter time to heat the polymer if higher flow rates are employed [25]. A different study from Lewandowski [57] observed the opposite effect for an intermeshing counter-rotating twin-screw extruder.…”

Section: Effect Of Volumetric Feeding Ratementioning

confidence: 97%

“…It allows bypassing multiple manufacturing steps such as the filament extrusion before the AM process, relieving the material to one extrusion cycle and leading to less degradation. Its versatility and design simplicity make SSE one of the essential equipment tools for the bulk polymer processing industry [22][23][24][25][26]. Most SSEs are fed by a granular solid polymer, which is melted or plasticized in the screw channel.…”

Section: Introductionmentioning

confidence: 99%

“…The extrusion process primarily consists of four elementary steps: handling of solid granules, melting, pumping, and mixing. Among these steps, understanding the melting is crucial for optimum SSE design and operation [23][24][25][26][27][28][29]. An excessively high melting rate and too long residence times can lead to substantial polymer degradation, while a too low melting rate can allow solid particles to reach the end of the metering zone affecting the extrusion rate stability.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Evaluation of the Melting Efficiency for the Single-Screw Micro-Extrusion Process: The Case of 3D Printing of ABS

et al. 2020

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One of the challenges for single-screw micro-extrusion or additive manufacturing (AM), thus 3D printing, of polymers is controlling the melting efficiency so that energy and equipment costs can be minimized. Here, a numerical model is presented for AM process design, selecting acrylonitrile–butadiene–styrene (ABS) as viscoelastic reference polymer. It is demonstrated that AM melting is different compared to conventional melting due to variation in extrusion dimensions, leading to a different balance in heating by conduction and viscous heat dissipation as caused by the shearing between the melt layers in the associated film layer near the barrel. The thickness of this melt film layer is variable along the screw length, and it is shown that simplified models assuming an overall average value are too approximate. It is highlighted that the screw frequency, pitch angle and compression ratio are important process parameters to control the point of melt finalization. In addition, the power-law index reflecting the shear thinning nature of the polymer melt is showcased as a key parameter. Moreover, AM process results assuming constant and temperature dependent specific heat capacities and thermal conductivities are compared. The current work opens the door for on-line AM process control, addressing all relevant operating and material parameters.

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Section: Effect Of Volumetric Feeding Ratementioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Theoretical Evaluation of the Melting Efficiency for the Single-Screw Micro-Extrusion Process: The Case of 3D Printing of ABS

et al. 2020

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“…Experimental measurements of polymeric liquids (solution and melt) are routinely carried out to obtain the necessary data on their rheological properties. Then, various numerical methods were used to find a suitable set of parameters for the rheology model to facilitate efficient flow simulations [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

An Iterative Approach for the Parameter Estimation of Shear-Rate and Temperature-Dependent Rheological Models for Polymeric Liquids

et al. 2021

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Numerical flow simulations play an important role in polymer processing. One of the essential prerequisites for accurate and precise flow simulations is to obtain accurate materials functions. In the framework of the generalized Newtonian fluid model, one needs to obtain shear viscosity as a function of the rate-of-shear and temperature—as determined by rheometry—and then fitted to a mathematical model. Often, many subjectively perform the fitting without paying attention to the relative quality of the estimated parameters. This paper proposes a unique iterative algorithm for fitting the rate-of-shear and temperature-dependent viscosity model under the time–temperature superposition (TTS) principle. Proof-of-concept demonstrations are shown using the five-parameter Carreau–Yasuda model and experimental data from small-amplitude oscillatory shear (SAOS) measurements. It is shown that the newly proposed iterative algorithm leads to a more accurate representation of the experimental data compared to the traditional approach. We compare their performance in studies of the steady isothermal flow of a Carreau–Yasuda model fluid in a straight, circular tube. The two sets of parameters, one from the traditional approach and the other from the newly proposed iterative approach, show considerable differences in flow simulation. The percentage difference between the two predictions can be as large as 10% or more. Furthermore, even in cases where prior knowledge of the TTS shifting factors is not available, the newly proposed iterative approach can still yield a good fit to the experimental data, resulting in both the shifting factors and parameters for the non-Newtonian fluid model.

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“…It is well known that polypropylene can be used to produce low-cost, lightweight, transparent, and flexible thin sheets and films for a variety of applications in industries [1]. The key component in the production of these sheets and films is the extrusion die designs [2,3]. Flow distribution channels in the extrusion dies should be designed in such a way to assure uniform fluid velocity, pressure, temperature in the outlets with uniform thickness [4,5].…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Thermal Flows in Entrance Channels for Polymer Extrusion: A Parametric Study

et al. 2020

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Flow distribution channels in extrusion dies are typically designed to assure uniform fluid velocity, pressure and temperature in the outlets. To ensure this uniformity, it is desirable to have the fluid melt to reach a steady state temperature in the entrance channel before entering the die body. This paper numerically investigates the temperature distribution of the fluid melt in the entrance channel. Analytical solutions of the velocity and finite element solutions of temperature distribution in Poiseuille flows of polypropylene melt with the Casson rheology model were derived and presented. In the velocity solution, the critical point that separates the core and the remaining parts in the flow was calculated by using the inlet flow rate and the yield stress in the Casson model. The velocity distribution was then substituted into the convective heat equation for temperature distribution simulations. A finite difference scheme was used to obtain the temperature distribution profiles along the flow direction in a parallel-plate, while the finite element model was used to model the flow temperature in circular tubes. The main outcome is the parametric analyses of the effect of various parameters such as radius, wall temperature, inlet temperature, and pressure drop to the optimal length of the channels required for the flow temperature to reach the steady state.

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Optimization of Polymer Extrusion Die Based on Response Surface Method

Cited by 14 publications

References 16 publications

Theoretical Evaluation of the Melting Efficiency for the Single-Screw Micro-Extrusion Process: The Case of 3D Printing of ABS

Theoretical Evaluation of the Melting Efficiency for the Single-Screw Micro-Extrusion Process: The Case of 3D Printing of ABS

An Iterative Approach for the Parameter Estimation of Shear-Rate and Temperature-Dependent Rheological Models for Polymeric Liquids

Numerical Modeling of Thermal Flows in Entrance Channels for Polymer Extrusion: A Parametric Study

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