Discrete Element Simulations of Powder Spreading in Additive Manufacturing

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Amrapurkar, P. (2020). Discrete Element Simulations of Powder Spreading in Additive Manufacturing. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

Powder spreading plays a critical role in the quality of parts produced with selective laser sintering (SLS). Some of the important parameters that influence the quality of the powder bed are the powder particle size and distribution, blade speed, blade - bed gap. In this work, the discrete element method is used to study the effect of these parameters on the quality of the powder bed. The interaction between the particles is modelled using Hertz-Mindlin with JKR contact model. The powder bed quality is quantified in the terms of mass flow rate (MFR) and packing density (PD) of powder. It is widely reported in the literature that increasing the packing density has the effect of reducing defects in the finished product. With the help of these quantities various factors affecting the powdered bed quality have been studied: cohesiveness of the particles, coefficient of restitution (COR), powder particle size and distribution, blade speed and gap. The results obtained from this study indicate that the powder particle size distribution is one of the major factor affecting the bed quality and as the blade - bed gap increases and blade speed decreases packing density increases. The blade - bed gap has no impact on MFR of the powder and cohesiveness has a wider impact on PD with smaller particle diameter.

Details
Author

Amrapurkar, Parth

Title

Discrete Element Simulations of Powder Spreading in Additive Manufacturing

Physical Description

1 online resource (61 pages) : PDF

Date

2020

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

Powder spreading plays a critical role in the quality of parts produced with selective laser sintering (SLS). Some of the important parameters that influence the quality of the powder bed are the powder particle size and distribution, blade speed, blade - bed gap. In this work, the discrete element method is used to study the effect of these parameters on the quality of the powder bed. The interaction between the particles is modelled using Hertz-Mindlin with JKR contact model. The powder bed quality is quantified in the terms of mass flow rate (MFR) and packing density (PD) of powder. It is widely reported in the literature that increasing the packing density has the effect of reducing defects in the finished product. With the help of these quantities various factors affecting the powdered bed quality have been studied: cohesiveness of the particles, coefficient of restitution (COR), powder particle size and distribution, blade speed and gap. The results obtained from this study indicate that the powder particle size distribution is one of the major factor affecting the bed quality and as the blade - bed gap increases and blade speed decreases packing density increases. The blade - bed gap has no impact on MFR of the powder and cohesiveness has a wider impact on PD with smaller particle diameter.

Genre

masters theses

Subjects--Topics

Mechanical engineering
Engineering
Physics

Degree

M.S.

Keywords

Additive Manufacturing
Applied sciences - Mechanics
Discrete Element Method (dem)
Metal 3D Printing
Powder Spreading
Selective Laser Sintering (SLS)

Subject Area

Mechanical Engineering

Advisor(s)

Cherukuri, Harish

Committee Members

Xu, Jun
Mullany, Brigid

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2020.

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Rights Holder Information

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Identifier

Amrapurkar_uncc_0694N_12473

Permalink

http://hdl.handle.net/20.500.13093/etd:1890