B. ANAND RONALD et al.: INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE PROPERTIES OF 3D PRINTED PLA
495–499
INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE
PROPERTIES OF 3D PRINTED PLA
VPLIV OSI IN KOTA GRADNJE NA LASTNOSTI 3D TISKANEGA
MODELA IZ POLILAKTI^NE KISLINE
B. Anand Ronald
*
, K. N. Mohammed Riaz Khan, G. Kishore, V. Lokesh,
R. K. Mullaivananathan
Department of Mechanical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, India
Prejem rokopisa – received: 2023-06-02; sprejem za objavo – accepted for publication: 2023-07-28
doi:10.17222/mit.2023.900
Additive manufacturing is one of the sought-after methods for on-demand printing of customized parts. Although it has several
advantages, namely design complexity, topologically optimized parts, tool-less and inventory-less manufacturing, etc., it also
has challenges in terms of print parameter-dependent mechanical properties. The present paper studies the influence of the build
orientation and angle on the tensile and flexural properties of fused-deposition-modelling (FDM) printed polylactic acid (PLA)
samples. The samples are printed in different orientations including 0°, 15°, 30°, 45°, 60°, 75° and 90° with respect to the X-
and Y-axis. From the tensile and flexural studies, we can infer that the orientation of the print plays a significant role, influenc-
ing the tensile and flexural properties. The X-axis build orientation and 75° build angle are preferred owing to better tensile and
flexural properties compared to the other angles and Y-orientation.
Keywords: fused deposition modelling, polylactic acid, build orientation, tensile and flexural properties
Dodajna tehnologija je nova zelo iskana metoda za izdelavo delov po naro~ilu ali prototipov. ^eprav ima mnogo prednosti, kot
so oblikovanje zahtevnih oblik in topolo{ko optimiziranih izdelkov, manj{e {tevilo orodij in manj{e stro{ke, predstavlja za
uporabnike tudi velike izzive vezane na parametre tiskanja in s tem povezane mehanske lastnosti izdelkov. V pri~ujo~em ~lanku
avtorji opisujejo {tudijo vpliva orientacije in kota gradnje (plasti za plastjo) na mehanske in natezne lastnosti vzorcev iz
polilakti~ne kisline (PLA, angl.: Poly Lactic Acid) izdelanih z metodo oblikovanja z nalivanjem oziroma nana{anjem taline
(FDM; angl.: Fused Deposition Modeling). Vzorce (natezne in upogibne preizku{ance) so tiskali pri orientacijah 0°, 15°, 30°,
45°, 60°, 75° in 90° z referen~no X ali Y osjo. Na osnovi rezultatov meritev natezne in upogibne trdnosti izdelanih vzorcev
avtorji ugotavljajo, da ima orientacija na mehanske lastnosti pomemben vpliv. Ugotavljajo tudi, da imajo vzorci izdelani z
orientacijo glede na X-os in gradnjo pod kotom 75° bolj{e natezne in upogibne lastnosti v primerjavi z uporabo drugih kotov in
Y-orientacije.
Klju~ne besede: metoda modeliranja z nana{anjem taline, polilakti~na kislina (PLA), orientacija gradnje modela, natezne in
upogibne lastnosti.
1 INTRODUCTION
Fused deposition modelling (FDM) is one of the
widely used methods for polymer additive manufactur-
ing, wherein a thermoplastic material in the form of fila-
ment is extruded layer by layer to get the desired prod-
uct.
1
For the current work, the thermoplastic chosen is
polylactic acid (PLA). Apart from consumer goods like
disposable tableware and cutlery, it finds application in
biodegradable medical devices like rods, pins, screws
and plates, especially for the components that need to de-
grade in a few months to a year.
2
Apart from customiz-
ation and design complexity possibility in additively
manufactured parts, it also permits tool-less, inven-
tory-less (on-demand printing is possible) manufactur-
ing. In spite of the above advantages, it also has certain
limitations in terms of the accuracy of the parts pro-
duced, print parameter-dependent mechanical properties,
removal of the support material, raw material limitations,
etc. Some researchers examined the accuracies of den-
tistry models printed using stereolithography apparatus
(SLA) and digital light processing (DLP) 3D printing
processes at various thicknesses. They created dental
pieces with a layer thickness of 20–100 μm. DLP-printed
dental models with a layer thickness of 100 μm showed
higher print accuracy. But in the case of SLA models,
they observed that as the thickness of layers decreased,
the printing accuracy was good.
3
Few researchers experi-
mented with a two-layer thickness and two different den-
sities of an ABS material. With 100-% infill densities
and layer thickness of 0.254 mm, they got better dimen-
sional accuracy behaviour.
From the studies on the effect of processing parame-
ters on the mechanical characteristics of PLA produced
with fused filament fabrication, researchers concluded
that as the infill density increased the tensile and
Young’s modulus values increased as well. However, the
infill patterns used, namely i) a gyroid ii) concentric iii)
square grid and iv) triangle, did not have any significant
impact on the properties.
4
Among the different process
parameters tried, namely the raster orientation, build ori-
entation, infill density, nozzle diameter, shell number,
Materiali in tehnologije / Materials and technology 57 (2023) 5, 495–499 495
UDK 7.021.5:539.382 ISSN 1580-2949
Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 57(5)495(2023)
*Corresponding author's e-mail:
anandronaldb@ssn.edu.in (B. Anand Ronald)

extrusion temperature, and extruding speed, the authors
found that build orientation, infill density and nozzle di-
ameter significantly influenced the part strength.
5,6
From
the fracture studies on FDM-printed PLA, the authors
concluded that the 0° raster direction gave a higher frac-
ture strength compared to the 45° and 90° orientation.
7
In
the study on the influence of different printing parame-
ters, namely the number of layers, layer height and
interfilament distance, on the tensile properties of 3D
printed, continuous flax/PLA biocomposites, the results
showed that by changing the layer height from 0.6 mm to
0.2 mm, the porosity was reduced and tensile properties
were improved. And when the number of layers was in-
creased owing to the compaction effect of the current
layer on the previous layer, better tensile properties were
observed. When the layer height was increased from
0.2 mm to 0.6 mm, there was a significant increase in the
porosity levels. When the interfilament distance was low,
there was a possibility of overlapping, leading to poros-
ity.
8
According to the study on the influence of the degree
of hollowness (0–30 % with a 10 % increment) on the
tensile and flexural properties of PLA, irrespective of the
type of material or internal porous structure, the proper-
ties decreased with increasing the hollowness level.
9
The
influence of the infill density and layer thickness on the
mechanical properties (tensile, fracture) was studied and
good tensile properties were found for the 0.3 mm layer
thickness and 80 % infill density.
10
Some researchers
also made a PLA–Cu composite filament wire with a
1.75 mm diameter that was FDM printed, followed by
shear and impact testing.
11
The studied literature mostly talks about understand-
ing the influences of the infill densities, infill pattern, a
few print angles (0°,45°,90°) and layer parameters (layer
height, interfilament distance) on the mechanical proper-
ties and dimensional accuracies using different printing
methods. However, the influences of intermediate angles
and build orientation axis on the mechanical properties
were not studied much according to the literature. Hence,
in the present work, the influence of the build orientation
axis and angle on the tensile and flexural properties of
FDM-printed PLA samples are studied.
2 EXPERIMENTAL PART
A Sharebot Viper fused deposition modeling machine
(Figure 1) was used for printing the PLA, having speci-
fications as follows: Nozzle Diameter: 0.4 mm, Filament
Diameter: 1.75 mm, Printing Speed: 60 mm/s, Layer
Thickness: 180 microns, Extrusion Temperature: 210 °C,
Bed Temperature: 35 °C, Infill Density: 100 %, Tool
Path Contour: Rectilinear. First, a CAD model of a sam-
ple was prepared using Autodesk Fusion 360 and slicing
was done using the Simplify 3D software. For this study,
dog bone tensile samples based on ASTM D638 Type 1
were printed. The samples were printed (Figure 2) for
0°, 15°, 30°, 45°, 60°, 75° and 90° in both orientations
(with respect toX&Y )a n dt h einfluence of the build
orientation axis and angle on the tensile and flexural
properties were studied.
The print material used was PLA +, having its Ten-
sile strength – 65 MPa; Elongation at break – 12 %; Den-
sity – 1.25 g/cm
3
; Melt flow index (g/10 min) – 4
(190°C/2.16 kg); Heat distortion temperature (°C,
0.45 MPa) – 52; Flexural strength – 75 MPa; Flexural
modulus – 2102 MPa; Izod impact – 8.5 KJ/m
3
, based on
the information provided by the supplier (eSUN Fila-
ments). Tensile tests were performed using UTM
WDW100 (Make: Jinan Testing Equipment IE Corpora-
B. ANAND RONALD et al.: INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE PROPERTIES OF 3D PRINTED PLA
496 Materiali in tehnologije / Materials and technology 57 (2023) 5, 495–499
Figure 2: Tensile and flexural samples Figure 1: SHAREBOT VIPER FDM machine

tion, having a load capacity of 100 kN. Flexural tests
were conducted on an MTS inside an EM 100 kN ma-
chine, following the ASTM D790 standard. Results for
the flexural modulus and flexural strength are reported in
the results and discussion section.
3 RESULTS AND DISCUSSION
3.1 Tensile properties for different print angles and
orientations
While performing mechanical tests, internal stresses
develop in the sample. A mechanical test is conducted up
to the limit when these internal stresses exceed the mate-
rial’s maximum bearing stresses. Referring to the illus-
trations in Figure 3 (stress-strain graph) and Figure 5,
we can conclude that the X75 sample showed an ultimate
tensile strength (UTS) value of around 44 MPa, and the
X90 sample showed a comparable value.
However, the strain % is better for the X90 sample
(13 %) compared to the X75 sample, which showed only
a 7 % strain. The strain % of the X90 sample is even
slightly higher than that of the initial raw wires (see ex-
perimental details), which shows that the bonding be-
tween layers was good, thereby providing good tensile
properties. The X0 sample also showed a strain
(ie., 11 %) comparable to that of X90, although its ulti-
mate tensile strength was relatively low. The X15 and
X60 samples showed relatively low UTS values.
On the illustration of the stress-strain characteristics
for the samples printed at different angles with respect to
the Y-orientation, shown in Figure 4, we can see an op-
posite trend. For higher print angles, the UTS was rela-
tively low and the strain % was also low. The Y0 sample
showed the highest ultimate tensile strength of around 36
MPa. The lowest UTS was observed for Y60 followed by
Y45. The strain % was also relatively high for the Y0
sample compared to any other sample. When printing in
the Y0 configuration, the number of layers needed for
the desired geometry is lower compared to the other
build angles; hence, only the bonding between a few lay-
ers is required, giving scope for relatively fewer defects.
On the contrary, Y90, Y75, Y60 and Y45 showed rela-
tively poor strain %, indicating a poor ductility compared
to the Y0 sample. The UTSs of these samples were also
relatively low compared to Y0. For higher build angles,
more layers are required and so the bonding between
many layers is required, leading to delamination of lay-
ers during the tensile testing.
12,13
From Figures 3, 4 and 5, it can be observed that the
X-oriented samples show better ultimate tensile strength
values, irrespective of the build angle, compared to the
Y-samples. At the 0° build angle, the orientation of the
build does not influence the UTS and % elongation val-
ues. However, at the 90° build angle, the orientation (X
or Y) of the print has a significant influence on the UTS
and % elongation values. As discussed earlier, when
B. ANAND RONALD et al.: INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE PROPERTIES OF 3D PRINTED PLA
Materiali in tehnologije / Materials and technology 57 (2023) 5, 495–499 497
Figure 4: Stress-strain graphs for Y-oriented samples
Figure 3: Stress-strain graphs for X-oriented samples
Figure 5: Comparison of the failure strain (elongation at break) and
tensile strength of the samples printed at different angles to the X- and
Y-orientations

samples are printed with their longer edge being the base
in the X-orientation, the number of layers is lower than
for the Y-orientation. The higher the number of layers for
the Y-orientation, the higher are the chances of improper
fusing. Also, the staircase effect in the case of curved
and inclined surfaces, typical of additively manufactured
parts, becomes more prominent for the Y-orientation
since more layers (more steps) are printed to get the de-
sired geometry.
14,15
3.2 Flexural properties for different print angles and
orientations
The capacity of a material to endure the bending
forces applied perpendicularly to its longitudinal axis is
known as the flexural strength. For biomedical applica-
tions like rods, pins, screws, plates, etc., the flexural
properties are important. According to Figure 6, for
most print angles the bending strength was in the
70 MPa (X15) to 90 MPa range (X75, X30). The flexural
strength for most print angles was almost equivalent to
that of the raw wire, i.e., 75 MPa. We can also infer that
the 75° print angle and X-axis build orientation allow
better flexural properties. For the Y-samples (Figure 7),
the trend of the flexural strength was similar to that of
the tensile samples with higher build angles showing a
poorer flexural strength, and lower angles showing a
better flexural strength. For most print angles there was
an overlap of the stress–strain graphs and hence, only a
few curves can be seen. Hence, we can observe that the
orientation of the build has a significant effect on the ten-
sile as well as flexural properties of the printed PLA ma-
terial.
From Figure 8, it can be observed that an increase in
the build angle increases the flexural modulus for both
X- and Y-samples in most cases. For a given build angle,
X-samples always exhibit a higher flexural strength than
Y-samples. Also, for a given angle, Y-samples show a
higher flexural modulus than X-samples.
4 CONCLUSIONS
From the above study of the influence of the build
orientation on the tensile and flexural properties of fused
deposition modelling (FDM) printed polylactic acid
(PLA), the following inferences can be made:
• From the study of the influences of the build orienta-
tion axis and build angle on the mechanical proper-
ties, we can infer that the X-oriented samples had
better tensile and flexural properties and the trend re-
versed when the print orientation was changed to the
Y configuration.
• The X75 orientation provided the highest tensile
strength value of 44 MPa and flexural properties on
par with the raw wire.
• Commercially used fused deposition modelling 3D
printers could very well be considered as an econom-
B. ANAND RONALD et al.: INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE PROPERTIES OF 3D PRINTED PLA
498 Materiali in tehnologije / Materials and technology 57 (2023) 5, 495–499
Figure 8: Comparisons of the flexural modulus and flexural strength
values of the samples printed at different angles for X- and Y-orienta-
tions Figure 6: Flexural stress-strain graphs for X-samples
Figure 7: Flexural stress-strain graphs for Y-samples

ical optiona for making useful parts with good me-
chanical properties under the above-mentioned print-
ing conditions.
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B. ANAND RONALD et al.: INFLUENCE OF THE BUILD AXIS AND ANGLE ON THE PROPERTIES OF 3D PRINTED PLA
Materiali in tehnologije / Materials and technology 57 (2023) 5, 495–499 499