experimental investigation of effect of printing

Experimental investigation of effect of printing parameters on impactstrength of the bio-inspired 3D printed specimen

MAHESH NAIK and DINESHSINGH G THAKUR*

Department of Mechanical Engineering, DIAT (DU), Ministry of Defence, Pune, Maharashtra 411 025, India

e-mail: [email protected]; [email protected]

MS received 27 August 2020; revised 15 March 2021; accepted 24 June 2021

Abstract. Additive Manufacturing (AM) has the ability to fabricate complex structures with bio-mimicry

features. Fused Deposition Modeling (FDM), which is AM technique, has the capability of creating complex

geometry parts in a short time. The mechanical properties of FDM build parts can be improved by selecting the

proper printing parameters. In the present study, the effect of printing parameters viz. printing orientation (flat

and on-edge) and infill density (20%, 35%, 50%, 65%, 80% and 100%) on the impact strength of bio-inspired 3D

printed specimen has been studied. The specimens with multi-infill pattern were inspired by bio-inspired

structure like a turtle shell. The multi-infill pattern specimen includes triangular, honeycomb and grid infill

patterns. Based on this multi-infill pattern, impact specimens were fabricated and tested. Impact strength and

impact strength/weight ratio of specimens in flat and on-edge orientation are measured and evaluated. The result

shows that the impact strength and impact strength/weight ratio of multi-infill pattern specimens printed in flat

orientation is less compared to specimens printed in on-edge orientation. The multi-infill pattern specimen with

20% infill density printed in on-edge orientation has the highest impact strength and impact strength/weight ratio

as compared to other specimens. Further, high magnification fracture surface analysis is performed to aid in the

characterisation of specimen failures.

Keywords. 3D-printing; FDM; PLA; bio-inspired specimen; impact strength.

1. Introduction

In 1986, Charles Hull first described the Additive Manu-

facturing (AM) technology, also known as 3D printing [1].

In recent decades, there has been a rise in many AM pro-

cesses that have brought benefits to engineering design and

manufacturing processes. 3D printing has the capability to

fabricate complex parts with high resolution and rapid

fabrication. It has the ability to assign material properties at

the sub-millimetre scale, inspiring multi-material, func-

tionally graded designs, thus making it an attractive option

for composite material development [2]. Additionally, 3D

printing simplifies the mimicking of bio-inspired structures

like honeycomb and molluscan shell [3–5]. The 3D printing

technique involves processes such as Fused Deposition

Modelling (FDM), Stereolithography (SLA), Laminated

Object Manufacturing (LOM), Binder Jetting (BJ), Selec-

tive Laser Melting (SLM) and Selective Laser Sintering

(SLS). Among these AM techniques, FDM is the most

widely used method due to its reliability, low cost and

minimised waste.

In the FDM process, a polymer in filament form is fed

into extrusion head. In extrusion head, the filament is

heated and the molten filament is extruded from the nozzle

and deposited on the heated plate to form the part layer-by-

layer as defined by the CAD data [6]. The schematic of the

FDM process is shown in figure 1. FDM printed parts have

their application in the field of aerospace, automobile,

biomedical and consumer part industries. However, the

poor mechanical properties of the FDM 3D printed part

restrict its application. By selecting proper printing

parameters, the mechanical properties of the FDM build

parts can be enhanced.

Recently, some work has been done by researchers to

improve the mechanical properties of the FDM build parts.

Sin et al used PLA with Blendex 338 as an impact modifier.

They observed that PLA, when blended with Blendex 338

showed increased impact strength [7]. Afrifah et al com-

bined PLA with ethylene/acrylate copolymer and found that

the combinations showed a decrease in tensile strength and

modulus with the increasing impact strength [8]. Lee et alstudied the influence of process parameters such as air gap,

layer thickness, raster angle and raster width in order to

achieve optimum elastic performance of a compliant ABS

prototype using the Taguchi method. They found that the

optimum level of parameters viz., air gap, raster angle,

raster width and layer thickness were double-wide, 30�/60�,0.980 mm and 0.178 mm, respectively [9]. Song et al*For correspondence

Sådhanå (2021) 46:151 � Indian Academy of Sciences

https://doi.org/10.1007/s12046-021-01671-8Sadhana(0123456789().,-volV)FT3](0123456789().,-volV)

compared the 3D-printed part with injection moulded part

and concluded that the 3D-printed parts have higher

toughness than injection moulded part [10]. Wang et alstated that higher printing temperature and lower layer

height improves the impact strength of the FDM build parts

[11]. Barner et al studied the effect of build orientation on

mechanical properties of specimens fabricated with the

honeycomb infill pattern printed using FDM technique. The

authors observed that the best results were obtained for the

edge-wise build orientation [12]. Sood et al stated that the

raster angle, layer thickness, build orientation, raster width

and air gap are important parameters and should be con-

sidered in the FDM technique. They concluded that these

parameters strongly influence the tensile, flexural and

impact properties [13]. It is noticed that most of the work is

devoted to enhance the mechanical properties of FDM build

part by studying various printing parameters. Nevertheless,

there has not been any research found on combinations of

different patterns and complex infill patterns in FDM build

PLA parts.

In this research, the aim is to study the effect of printing

orientation and infill density on the impact strength of

multi-infill pattern specimen. The multi-infill pattern

specimen was inspired by the turtle shell. The turtle shell

structure observation revealed that it comprises a multi-

phase sandwich composite structure with functionally gra-

ded pores which helps to absorb mechanical shocks, deliver

nutrients and behave as a lightweight armour to the turtle

[14]. Hence, to obtain the functionally graded pores in the

specimen, multi-infill pattern was considered. The multi-

infill pattern specimen consists of three infill pattern, viz.,

grid, honeycomb and triangular pattern placed one above

other along the thickness direction. These three patterns

were selected due to their highest strength and they weight

lighter compared to solid [15]. The honeycomb pattern has

the highest strength, so it was considered in the middle and

the grid and triangular pattern were considered on both

sides of honeycomb pattern. The multi-infill pattern with

porous structure will provide a base for the design of a

lightweight structure. Moreover, the primary goal of

industries is to fabricate lightweight products. By selecting

the optimum infill density and infill pattern, it is possible to

reach the highest strength with lightweight products. The

multi-infill pattern structure can have its application in the

medical and aerospace field. In medical field, the pores

structure can help in growth and migration of cells, whereas

in aerospace field, the multi-infill pattern structure can help

to obtain maximum strength/weight ratio of parts. The

material used in this research is a thermoplastic called

polylactic acid (PLA), which is cost-effective and

biodegradable. The multi-infill pattern specimens were 3D

printed and tested as per ASTM D256 standard test meth-

ods for determining impact strength and impact strength/

weight ratio. Further, to understand the failure mode, the

fracture surface of the specimens is microscopically

studied.

2. Experimental details

2.1 FDM machine

An entry-level, INDICBOTTURBO 300 dual extruder, a

high-precision 3D printer that uses the FDM technique, was

used to fabricate the impact test specimens. Each specimen

was printed individually in the middle of the build plate to

minimise the effect of positioning error. The 3D printer has

a build volume of 300 mm 9 300 mm 9 300 mm. The

nozzle diameter is 0.4 mm, and the capability to print

minimum layer height is 0.1 mm. The 3D printer has a

maximum printing speed of 100 mm/sec. The temperature

range of the extrusion nozzle is 25�C–260�C and the

printing bed is 25�C–120�C. Further, the printer supports

various types of polymer materials such as PLA, ABS,

HIPS, PET-G and Nylon in filament form, having a diam-

eter of 1.75 mm.

2.2 Material

In the present study, the filament material selected is PLA.

It is a thermoplastic polymer, and in 1920 it was invented

by Wallace Carothers. PLA is a high-modulus and high-

strength polymer. It is easily processable on standard

plastic equipment to yield moulded parts, film, or fibres.

PLA exhibit mechanical properties that are comparable

with those of petro-based commercial polymers. Further, it

can be decomposed in the environment and human body. In

this research, a PLA filament of diameter 1.75 mm with a

tolerance of ±0.03 mm was used to print the specimens.

The PLA filament spool was supplied by Rever industries,

India.

Figure 1. Schematic of the FDM Process.

151 of 9 Sådhanå (2021) 46:151

2.3 Printing parameters

The impact strength of the 3D-printed part is primarily

dependent on the selection of the printing parameters.

Hence, in the present study, the two key printing parame-

ters: printing orientation (Flat and On-edge) as shown in

figure 2 and percent infill density (20%, 35%, 50%, 65%,

80% and 100%) as shown in figure 3 are selected for the

investigation of impact strength of multi-infill pattern

specimen. Table 1 shows the fixed printing parameters that

are considered during the printing of multi-infill pattern

impact specimens.

2.4 Fabrication of specimen

The 3D CAD model of the test specimen was created in

Solidworks 2018 and exported as an STL file, and

according to ASTM D256 (ASTM 2010) [16], the geometry

was set as shown in figure 4. The STL file is then uploaded

into the slicing software, where it sliced the STL file to

create tool pathways and export the instructions as a

G-Code file. Then the G-Code file is submitted to an

INDICBOTTURBO 300 dual extruder 3D printer to print

the multi-infill pattern impact specimens. The multi-infill

pattern specimens were created using the multi-process

function of the slicer software. In the case of on-edge ori-

entation, it consists of four sections, i.e. 100% infill density,

triangular pattern, honeycomb pattern and grid pattern

sections from top to bottom respectively along width

direction and in case of flat orientation, it consists of three

sections, i.e. triangular pattern, honeycomb pattern and grid

pattern sections from top to bottom respectively along

thickness direction as shown in figure 5. The 3D sections of

multi-infill pattern specimen for flat orientation with dif-

ferent infill pattern distribution is shown in figure 6. Also,

figure 7 shows the 3D printed specimens for the izod impact

test.

2.5 Izod impact testing of 3D printed specimen

The izod impact specimens were tested on an IT 503 izod

impact tester. The tester features heavy-duty construction

with a solid steel base and thick-walled column. It consists

of the compound pendulum, which has been aerodynami-

cally designed to provide maximum rigidity and virtually

eliminates windage losses. Low friction bearings are fitted

to reduce mechanical losses. The tester incorporates a

microprocessor system, which automatically calculates and

displays the impact energy absorbed by a specimen. Before

testing, a simple calibration of the machine is done, which

automatically calculates the windage and friction losses and

subtracts from the final reading. The IT 503 impact tester

includes a standard pendulum capable of delivering nomi-

nal energy of 2.82 Joules at a 610 mm drop height, and by

adding optional weights, the pendulum capacity can be

increased up to 25 Joules.

The Izod impact testing is carried out as per ASTM D256

standards. Five impact test specimens were printed and

tested at each printing orientation and infill density. In this

test, the notched specimen was fixed between the vices at

one end of the specimen, which resulted in the specimen

being held in a cantilever position (figure 8 for the equip-

ment set-up). Clamping was done only finger-tight to pro-

vide a secure base for the specimen. The pendulum carrying

the Izod striking bit strikes the specimen on the unsecured

end. Before starting the test, the arm of the pendulum is set

to 0� and then it is released. During the Izod impact test, the

specimen is subjected to a rapid and intense blow from a

pendulum that hits the specimen. The energy absorbed by

the specimen until failure is known as the impact energy.

Impact strength is calculated by taking the ratio of impact

energy to the thickness of the specimen.

2.6 Morphology

Scanning Electron Microscopy (SEM) analysis was

employed to characterise the failure of the specimens. The

morphology of fracture surfaces of the 3D printed PLA

specimens was observed using SEM (SIGMA, Carl Zeiss

Field Emission Scanning Electron Microscopy). The frac-

ture surface of the specimens was coated with gold before

SEM examinations.

3. Results and discussion

The multi-infill pattern impact specimens were tested by

considering two printing orientation and six percent infill

density. The printing time of specimens, weight of speci-

mens and values obtained from the impact tests such as

impact strength and impact strength/weight ratio were listed

in table 2. The combination of each printing orientation and

percent infill density showed different results and different

fracture styles.

3.1 Printing time and weight of specimen

Figure 9 shows the printing time vs infill density of multi-

infill pattern specimens printed with flat and on-edge build

orientation. The x-axis represents infill density and the

y-axis represents printing time. Figure 10 shows the weight

vs infill density of multi-infill pattern specimens printed

with flat and on-edge build orientation. The x-axis repre-

sents infill density, and the y-axis represents weight. From

figures 9 and 10, it is observed that the printing time and

weight increases as the percent infill density increases for

specimens in both orientations. As the percent infill density

increases, the volume occupied by polymer material

Sådhanå (2021) 46:151 of 9 151

increases which results in more deposition of material.

Also, the printing time and weight are more for specimens

printed in on-edge orientation compared to specimens

printed in flat orientation. In the case of on-edge orienta-

tion, the layer-by-layer printing is done along the width

direction, whereas in a flat orientation, the layer-by-layer

printing is done along the thickness direction. This results

in more volume occupied by the counters in on-edge ori-

entation as compared to flat orientation. Due to this, the

printing time and weight of specimens printed in on-edge

orientation are more than flat orientation.

Figure 3. 3D views of izod impact specimens for flat orientation with different percent infill density (a) 20%, (b) 35%, (c) 50%,

(d) 65%, (e) 80% and (f) 100%.

Figure 2. 3D views of printing orientations of izod impact specimen.

Table 1. Fixed printing parameters.

Sl. no. Printing parameters Value

1. Nozzle temperature (�C) 200

2. Bed temperature (�C) 60

3. Printing speed (mm/sec) 40

4. Layer Height (mm) 0.15

5. Number of contours 2

6. Nozzle size (mm) 0.4

Figure 4. 2D geometry of izod impact test specimen as per ASTM D256.

151 of 9 Sådhanå (2021) 46:151

3.2 Impact strength and impact strength/weightratio

Figure 11 depicted the effect of build orientations and

percentage infill density on impact strength of the FDM

build multi-infill pattern specimens. From figure 11, it is

observed that multi-infill pattern specimen printed in on-

edge orientation has higher impact strength compared to

that of flat orientation. In flat orientation specimens, less

raster meeting junction of infill patterns and fewer counter

layers come in contact with the impact load as the build

direction of the specimen is along the thickness direction

whereas, for on-edge orientation specimens, more raster

meeting junction of infill patterns and more counter layers

Figure 8. Experimental set-up for the izod impact test.

Figure 7. 3D printed izod impact test specimens.

Figure 5. Sections of multi-infill pattern specimen for two orientations.

Figure 6. 3D sections of flat orientated multi-infill pattern specimen with infill pattern distribution (50% infill density specimen).

Sådhanå (2021) 46:151 of 9 151

come in contact with the impact load as the build direction

of the specimen is along the width direction. Also, the

specimens with different infill density in both orientations

show different impact strength. These difference in impact

strength for multi-infill pattern specimens can be explained

by fracture styles associated with them. Figure 12 shows

the SEM images of fractured surfaces of multi-infill pattern

specimens with different infill density in both orientations.

In figure 12, the red, blue and yellow box represents the

fracture surface of triangular, honeycomb and grid infill

pattern respectively of multi-infill pattern specimen.

In flat orientation, the multi-infill pattern specimen with

50% infill density has the highest impact strength of

95.57 J/m, and the specimen with 20% infill density has the

lowest impact strength of 80.29 J/m. The specimen with

35%, 65%, and 80% infill density has nearly the same

impact strength of 85.19 J/m, 86.08 J/m and 85.63 J/m,

respectively. The specimen with 100% infill density has an

impact strength of 92.09 J/m. For flat orientation

Table 2. Summarised izod impact testing results.

Printing Orientation Infill Density (%) Print Time (min) Weight (g) Impact Strength (J/m) Impact Strength/Weight ratio (J/mg)

Flat 20 11 1.05 80.29 76.47

35 13 1.34 85.19 63.42

50 15 1.63 95.57 58.63

65 17 1.82 86.08 47.21

80 19 2.09 85.63 40.97

100 21 2.35 92.09 39.13

On-edge 20 22 2.16 212.74 98.64

35 23 2.26 171.90 76.18

50 24 2.31 159.68 69.03

65 25 2.41 176.61 73.38

80 26 2.46 198.78 80.80

100 27 2.55 190.58 74.64

20 35 50 65 80 1000.0

0.5

1.0

1.5

2.0

2.5

3.0

Wei

ght (

g)

Infill Density (%)

Flat Onedge

Figure 10. Comparison of the weight of the impact specimens.

20 35 50 65 80 1000

50

100

150

200

250

Impa

ct S

tren

gth

(J/m

)

Infill Density (%)

FlatOnedge

Figure 11. Comparison of impact strength of the specimens.

20 35 50 65 80 1000

5

10

15

20

25

30

Prin

ting

Tim

e (m

in)

Infill Density (%)

FlatOnedge

Figure 9. Comparison of the printing time of the impact

specimens.

151 of 9 Sådhanå (2021) 46:151

specimens, it is observed from figures 12(a-f) that the

fracture in the specimen with 20% infill density is due to

failure at raster meeting junction of triangular and honey-

comb pattern and trans-raster failure of the grid pattern.

Due to the availability of less material to resist load, 20%

infill density specimen shows less impact strength. For the

35% infill density specimen, the fracture is due to failure at

raster meeting junction of all three infill pattern. For 50%

infill density specimen, the fracture is due to the

combination of trans-raster failure and failure at raster

meeting junction of triangular pattern, failure at raster

meeting junction of honeycomb pattern and individual

raster failure of the grid pattern. Due to these different

fracture styles and strong fusion of bond at raster meeting

junction, the specimen with 50% infill density has the

highest impact strength. For 65% infill density specimen,

the fracture is due to individual raster failure of triangular

pattern and failure at raster meeting junction of honeycomb

Figure 12. SEM images of fracture surface of izod impact specimens.

Sådhanå (2021) 46:151 of 9 151

and grid pattern. For 80% infill density specimen, the

fracture is due to failure at raster meeting junction of tri-

angular and grid pattern and trans-raster failure of honey-

comb pattern. In 35%, 65% and 80% infill density

specimen, even though the infill density increases the

impact strength is nearby same for these three specimens.

This is due to the presence of different fracture styles in

these specimens. For 100% infill density, the fracture is due

to pulling and rupturing of rasters in all three infill pattern.

Due to this, there is more deformation of raster before

failure which results in more impact strength. It is observed

that most of the failure in multi-infill pattern specimen with

flat orientation is due to failure at the raster meeting junc-

tion. Failure occurs in these regions where rasters fuse and

make a bond. The strength of the bond depends on the

fusion of material at the raster interface. But, due to the

presence of voids and incomplete bond fusion, the bond

forms at the raster interface are weaker. Moreover, the

junction points also act as stress concentration points, and

failure occurred due to the breakage of bonding at these

junction points.

In on-edge orientation, the multi-infill pattern specimen

with 20% infill density has the highest impact strength of

212.74 J/m and the specimen with 50% infill density has

the lowest impact strength of 159.68 J/m. The specimen

with 35%, 65%, 80% and 100% infill density has an impact

strength of 171.90 J/m, 176.61 J/m, 198.78 J/m and

190.58 J/m, respectively. For on-edge orientation speci-

mens, it is observed from figures 12 (g-l) that the fracture in

the specimen with 20% infill density is due to failure at

raster meeting junction of triangular and grid pattern and

individual raster failure of honeycomb pattern. Individual

raster can take more impact load than the bonding between

the rasters. Also, due to less infill density, the gap between

rasters are more which resulted in more deformation of

individual raster before fracture. Due to the individual

raster failure and more deformation of raster in the hon-

eycomb pattern and failure at raster meeting junction of

triangular and grid pattern, 20% infill density specimen

shows high impact strength. For 35%, 50% and 65% infill

density specimen, the fracture is due to failure at raster

meeting junction of triangular pattern, individual raster

failure of honeycomb pattern and trans-raster failure of the

grid pattern. For 50% infill density specimen, the presence

of gap in grid pattern at fracture surface is more compared

to 35% and 65% which resulted in less impact strength of

specimen. For 80% infill density specimen, the fracture is

due to failure at raster meeting junction of triangular and

grid pattern and trans-raster failure of honeycomb pattern.

For 100% infill density specimen, the failure is due to

brittle fracture in all three infill pattern. Also, in all on-edge

orientation specimens the failure is due to voids present at

the raster interface, and the formation of ratchet lines

(R) leads to form a crack which promotes failure.

Figure 13 shows the influence of build orientation and

percent infill density on the impact strength/weight ratio of

multi-infill pattern in both orientations. From figure 13, it

can be stated that the specimens printed in flat orientation

with 20% and 100% infill density have high and low impact

strength/weight ratio, respectively. For specimens in on-

edge orientation, the 20% and 50% infill density specimens

have high and low impact strength/weight ratio. Moreover,

the specimen with an on-edge orientation with 20% infill

density has the highest impact strength/weight ratio of

98.64 J/mg compared to other specimens in both orienta-

tions. This variation in impact strength/weight ratio of the

specimen in both orientations is due to the varying weight

of specimen and varying fracture styles which leads to

varying impact strength/weight ratio of specimens.

4. Conclusion

The experiments were carried out to study the effects of

printing orientations and infill density on the impact

strength of muti-infill pattern specimens built by FDM

technique. The experimental investigation also includes the

study of SEM images of fracture surfaces. The results of

this study are summarised below:

• The Izod impact test result shows that the multi-infill

pattern specimen printed in on-edge orientation

exhibits higher impact strength in comparison to the

multi-infill pattern specimen printed in flat orientation.

• The 20% infill density specimen printed in on-edge

orientation has the highest impact strength and impact

strength/weight ratio.

• The printing time and weight of multi-infill pattern

specimens printed in on-edge orientation are higher in

20 35 50 65 80 1000

20

40

60

80

100

Impa

ct S

tren

gth/

Wei

ght R

atio

(J/m

g)

Infill Density (%)

FlatOnedge

Figure 13. Comparison of impact strength/weight ratio of the

specimens.

151 of 9 Sådhanå (2021) 46:151

comparison to the multi-infill pattern specimen printed

in flat orientation.

• The printing time and weight of specimens increase

with an increase in infill density for all multi-infill

pattern specimens in both orientations.

• The SEM images of the fracture surface reveal that the

multi-infill pattern specimen in both the orientation

shows varying failure styles such as trans-raster failure,

failure at raster meeting junction, individual raster

failure, pulling and rupturing of rasters and brittle

fracture. Due to the presence of different fracture

styles, the specimens show varying result for different

infill density and orientation.

The results of this study can be scaled up for the appli-

cation where strength/mass ratio is important. Combining

different infill patterns can be used in different applications

to achieve stronger products. The application of the multi-

infill pattern specimens can be extended to the aerospace,

automobile and medical field, where lightweight structures

are desirable.

AbbreviationsAM Additive Manufacturing

FDM Fused Deposition Modeling

PLA Poly-lactic Acid

3DP Three Dimensional Printing

SLA Stereolithography

LOM Laminated Object Manufacturing

SLM Selective Laser Melting

SLS Selective Laser Sintering

CAD Computer-Aided Design

ABS Acrylonitrile Butadiene Styrene

ASTM American Society for Testing and Materials

HIPS High Impact Polystyrene

PET-G Polyethylene Terephthalate Glycol

SEM Scanning Electron Microscopy

References

[1] Govil K, Kumar V, Pandey D P, Praneeth R and Sharma A

2019 Additive Manufacturing and 3D Printing: A Perspec-

tive. In: Prasad A, Gupta S, Tyagi R (eds). Advances inEngineering Design. Lecture Notes in Mechanical Engineer-ing. Singapore, Springer, 321–334

[2] Quan Z, Wu A, Keefe M, Qin X, Yu J, Suhr J, Byun J

H, Kim B S and Chou T W 2015 Additive manufac-

turing of multi-directional preforms for composites:

opportunities and challenges. Mater. Today. 18: 503–512[3] Korde J M, Shaikh M and Kandasubramanian B 2018

Bionic prototyping of honeycomb patterned polymer

composite and its engineering application. Polym. Plast.Tech. Eng. 57: 1828–1844

[4] Yadav R, Naebe M, Wang X and Kandasubramanian B

2017 Review on 3D prototyping of damage tolerant

interdigitating brick arrays of nacre. Ind. Eng. Chem.Res. 56: 10516–10525

[5] Deoray N and Kandasubramanian B 2018 Review on

three-dimensionally emulated fiber-embedded lactic acid

polymer composites: opportunities in engineering sector.

Polym. Plast. Tech. Eng. 57: 860–874[6] Chua C K and Leong K F 2014 3D Printing and

Additive Manufacturing: Principles and Applications.

Rapid Prototyping, Fourth Edition. World Scientific

Publishing Company

[7] Sin LT, Rahmat A R and Rahman W A 2012 Handbookof Biopolymers and Biodegradable Plastics: Properties,Processing and Applications. Elsevier, Amsterdam

[8] Afrifah K A and Matuana L M 2010 Impact modifica-

tion of polylactide with a biodegradable ethylene/acry-

late copolymer. Macromol. Mater. Eng. 295: 802–811[9] Lee B H, Abdullah J and Khan Z A 2005 Optimisation

of rapid prototyping parameters for production of

flexible ABS object. J. Mater. Process. Technol. 169:

54–61

[10] Song Y, Li Y, Song W, Yee K, Lee K Y and Tagarielli V L

2017 Measurements of the mechanical response of unidirec-

tional 3D-printed PLA. Mater. Des. 123: 154–164[11] Wang L, Gramlich W M and Gardner D J 2017

Improving the impact strength of Poly lactic acid

(PLA) in fused layer modeling (FLM). Polymer 114:

242–248

[12] Barner S 2015 Mechanical properties of additive man-ufactured honeycomb structures. Doctoral dissertation

Thesis, Clenson University, Columbia, United States

[13] Sood A K, Ohdar R K and Mahapatra S S 2010 Parametric

appraisal of mechanical property of fused deposition mod-

elling processed parts. Mater. Des. 31: 287–295[14] Ding X F, Jiang L, Liang Y and Wu C W 2011 The

structure and mechanical properties of turtle shell and

biomimetic. Adv. Mat. Res. 189: 3419–3422[15] Lalegani D M and Mohd Ariffin M K 2020 The effects

of combined infill patterns on mechanical properties in

FDM process. Polymers 12: 2792

[16] ASTM D256 2010 Standard Test Methods for Deter-mining the Izod Pendulum Impact Resistance of Plastics,ASTM International, West Conshohocken, PA

Sådhanå (2021) 46:151 of 9 151

experimental investigation of effect of printing

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