Citation: Abdelmoula, M.;
Küçüktürk, G. Multi-Layer
Simulation of the Powder Bed
Selective Laser Processing of
Alumina for Residual Stress and
Distortion Evaluation. Materials 2022,
15, 3498. https://doi.org/10.3390/
ma15103498
Academic Editors: Ludwig Cardon
and Clemens Holzer
Received: 9 April 2022
Accepted: 8 May 2022
Published: 13 May 2022
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Article
Multi-Layer Simulation of the Powder Bed Selective Laser
Processing of Alumina for Residual Stress and
Distortion Evaluation
Mohamed Abdelmoula and Gökhan Küçüktürk *
Department of Mechanical Engineering, Gazi University, Ankara 06500, Turkey; mohamedeid@gazi.edu.tr
* Correspondence: gkucukturk@gazi.edu.tr
Abstract:
A numerical model was developed to simulate the real process of alumina powder bed
selective laser processing (PBSLP) to thoroughly investigate the residual stress and distortion ex-
perienced in printed parts when multi-layer scanning with a CO
2
laser source is considered. The
model contains a user-defined function (UDF) for the laser source, temperature-dependent material
properties, scanning strategies, and build orientations, and it is solved using ANSYS 2020R2. In
addition, the model’s validation was confirmed with experimental results. The results revealed that a
high scanning speed (up to 1200 mm/s) and low laser power are effective for the PBSLP of alumina,
owing to alumina’s high absorptivity for CO
2
lasers, and a high manufacturing rate can be achieved.
During the multi-layer printing simulation, the accumulated heat inside the part increased gradually
with an increased number of printed layers. Additionally, the calculated residual stress exceeded
the yield limit for all the studied build orientations due to the printed part’s high-temperature
difference. When preheating was applied, the residual stress decreased by 23% and the distortion de-
creased by 54%. For the successful PBSLP of ceramics, commercial printers cannot be used effectively.
A particular printer equipped with a temperature controller and a preheating system is required
for ceramics.
Keywords: selective laser processing; alumina; CO
2
laser; build orientations
1. Introduction
Ceramic materials represent one of the most important material classes, with nu-
merous applications in a variety of fields due to their distinct mechanical and physical
properties [
1
]. These properties include low density, high hardness, biocompatibility, and
corrosion resistance [
2
–
5
]. Ceramic parts are manufactured using traditional methods
such as casting, extrusion, injection molding, and pressing [
6
–
9
]. The problem with these
techniques is that they cannot keep up with the current manufacturing revolution that
involves the production of highly complex designs. Furthermore, ceramic parts produced
using these traditional techniques require post-treatment operations to achieve the final
shape, which incurs additional costs and creates problems such as shrinkage [10,11].
Additive manufacturing (AM) technology has the potential to be an effective solu-
tion because of its ability to produce highly complex designs [
12
–
14
]. AM is a trending
manufacturing technology which is used to produce parts from 3D CAD models layer by
layer [
15
]. AM has seven techniques defined by ISO/ASTM 52900, i.e., powder bed selec-
tive laser processing (PBSLP), binder jetting, vat-photopolymerization, extrusion, direct
energy deposition, material jetting, and sheet lamination [15].
Nowadays, the AM of ceramics is undergoing rapid developments, whether in terms
of feedstock or the application of AM techniques. Many studies have been conducted on
the AM of ceramic materials using various techniques such as binder jetting, extrusion,
and PBSLP [
16
–
29
]. Among the techniques used, PBSLP is regarded as the most suitable
for ceramic materials because it can produce a dense structure with more accurate shape
Materials 2022, 15, 3498. https://doi.org/10.3390/ma15103498 https://www.mdpi.com/journal/materials
