Numerical simulation of a core–shell polymer strand in material extrusion additive manufacturing

TY - JOUR

T1 - Numerical simulation of a core–shell polymer strand in material extrusion additive manufacturing

AU - Narei, Hamid

AU - Fatehifar, Maryam

AU - Malt, Ashley Howard

AU - Bissell, John

AU - Souri, Mohammad

AU - Esfahani, Mohammad Nasr

AU - Jabbari, Masoud

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/2/2

Y1 - 2021/2/2

N2 - Material extrusion additive manufacturing (ME-AM) techniques have been recently intro-duced for core–shell polymer manufacturing. Using ME-AM for core–shell manufacturing offers improved mechanical properties and dimensional accuracy over conventional 3D-printed polymer. Operating parameters play an important role in forming the overall quality of the 3D-printed manu-factured products. Here we use numerical simulations within the framework of computation fluid dynamics (CFD) to identify the best combination of operating parameters for the 3D printing of a core–shell polymer strand. The objectives of these CFD simulations are to find strands with an ultimate volume fraction of core polymer. At the same time, complete encapsulations are obtained for the core polymer inside the shell one. In this model, the deposition flow is controlled by three dimen-sionless parameters: (i) the diameter ratio of core material to the nozzle, d/D; (ii) the normalised gap between the extruder and the build plate, t/D; (iii) the velocity ratio of the moving build plate to the average velocity inside the nozzle, V/U. Numerical results of the deposited strands’ cross-sections demonstrate the effects of controlling parameters on the encapsulation of the core material inside the shell and the shape and size of the strand. Overall we find that the best operating parameters are a diameter ratio of d/D = 0.7, a normalised gap of t/D = 1, and a velocity ratio of V/U = 1.

AB - Material extrusion additive manufacturing (ME-AM) techniques have been recently intro-duced for core–shell polymer manufacturing. Using ME-AM for core–shell manufacturing offers improved mechanical properties and dimensional accuracy over conventional 3D-printed polymer. Operating parameters play an important role in forming the overall quality of the 3D-printed manu-factured products. Here we use numerical simulations within the framework of computation fluid dynamics (CFD) to identify the best combination of operating parameters for the 3D printing of a core–shell polymer strand. The objectives of these CFD simulations are to find strands with an ultimate volume fraction of core polymer. At the same time, complete encapsulations are obtained for the core polymer inside the shell one. In this model, the deposition flow is controlled by three dimen-sionless parameters: (i) the diameter ratio of core material to the nozzle, d/D; (ii) the normalised gap between the extruder and the build plate, t/D; (iii) the velocity ratio of the moving build plate to the average velocity inside the nozzle, V/U. Numerical results of the deposited strands’ cross-sections demonstrate the effects of controlling parameters on the encapsulation of the core material inside the shell and the shape and size of the strand. Overall we find that the best operating parameters are a diameter ratio of d/D = 0.7, a normalised gap of t/D = 1, and a velocity ratio of V/U = 1.

KW - Additive manufacturing

KW - CFD

KW - Core–shell polymer strand

KW - Material extrusion

KW - Processing parameters

UR - http://www.scopus.com/inward/record.url?scp=85100461824&partnerID=8YFLogxK

U2 - 10.3390/polym13030476

DO - 10.3390/polym13030476

M3 - Article

AN - SCOPUS:85100461824

SN - 2073-4360

VL - 13

JO - Polymers

JF - Polymers

IS - 3

M1 - 476

ER -