Revista Científica Interdisciplinaria Investigación y Saberes
2022, Vol. 13, No. 1 e-ISSN: 1390-8146
Published by: Universidad Técnica Luis Vargas Torres
How to cite this article (APA): Merizalde-Salas, C., Zumba, E., Peralta-Zurita, D. (2023) Alternative
Material for the plastic injection molding of the Kia Rio's ventilation grille. Revista Científica
Interdisciplinaria Investigación y Saberes, 13(1) 1-25
Alternative Material for the plastic injection molding of the Kia Rio's
ventilation grille
Material alternativo para el moldeo por inyección de plástico de la rejilla de ventilación
del Kia Rio
Alex Merizalde-Salas
Carlos Cisneros Technological Institute, La Paz 07-56 & Mexico, 060110, Riobamba, Ecuador.
alex.merizalde@itscarloscisneros.edu.ec, https://orcid.org/0000-0002-0469-5079
Ember Zumba-Novay
Escuela Superior Politecnica de Chimborazo, Ent. 1 ESPOCH, Panamerican Highway South km 1 ½,
060155, Riobamba, Ecuador. ezumba@espoch.edu.ec, https://orcid.org/0000-0002-2121-8418
Diana Belén Peralta-Zurita
Universidad Internacional SEK del Ecuador, diana.peralta@uisek.edu.ec, https://orcid.org/0000-0002-
9523-0743
This research was based on the selection of an alternative material for
the manufacture by plastic injection of the Kia Rio's ventilation grille.
This accessory has a high acquisition cost because the vast majority
are imported elements. Therefore, a composite material was sought
that can replace the original, which was found in a local environment
and is applicable in the plastic injection manufacturing process. The
COPRAS multi-criteria method was used to choose the ideal material
to replace the original, which was ABS-PC, with PP-20% Bamboo
fiber. Finally, once the ideal candidate has been obtained, the next
step was to carry out simulations of the plastic injection process with
computational fluid dynamics (CFD) analysis software for plastics;
these simulations were carried out for the original material. The results
obtained by the multicriteria selection criterion showed that PP-20%
bamboo fiber is the ideal candidate to replace the original. This result
was corroborated by the CFD simulation that demonstrated that it has
the best characteristics to be applied in the plastic injection process.
Keywords:
COPRAS, computational fluid dynamics, plastic injection
molding, bamboo fiber, Ecuador.
Abstract
Received 2022-06-12
Revised 2022-06-14
Accepted 2022-11-30
Published 2023-01-11
Corresponding Author
Alex Merizalde-Salas
Alex.merizalde@itscarloscisneros.
edu.ec
Pages: 1-25
https://creativecommons.org/lice
nses/by-nc-sa/4.0/
Distributed under
Copyright: © The Author(s)
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
2
Resumen
Esta investigación se basó en la selección de un material alternativo
para la fabricación por inyección de plástico de la rejilla de ventilación
del Kia Rio. Este accesorio tiene un alto costo de adquisición porque
la gran mayoría son elementos importados. Por lo tanto, se buscó un
material compuesto que pueda sustituir al original, que se encuentre
en el medio local y que sea aplicable en el proceso de fabricación por
inyección de plástico. Se utilizó el método multicriterio COPRAS para
elegir el material ideal para sustituir al original, que era ABS-PC, con
PP-20% de fibra de bambú. Finalmente, una vez obtenido el
candidato ideal, el siguiente paso fue realizar simulaciones del
proceso de inyección de plástico con software de análisis de dinámica
de fluidos computacional (CFD) para plásticos; estas simulaciones se
realizaron para el material original. Los resultados obtenidos
mediante el criterio de selección multicriterio mostraron que el PP-
20% de fibra de bambú es el candidato ideal para sustituir al original.
Este resultado fue corroborado por la simulación CFD que demostró
que posee las mejores características para ser aplicado en el proceso
de inyección de plásticos.
Palabras clave:
COPRAS, dinámica de fluidos computacional, moldeo
por inyección de plástico, fibra de bambú, Ecuador.
Introduction
Most of the parts that make up the aesthetics and interior functioning
of the vehicles are made of plastics and their manufacturing process
is the injection of plastic which requires a high investment capital for
production, (Holmes 2020). In Ecuador the importing and assembling
companies spent about 1,557 million dollars among all types of auto
parts, generally for the assembly of vehicles leaving very little for
spare parts and to a lesser extent for the replacement of parts such as
vents. In the automotive industry the use of polymers is widespread
due to the characteristics they exhibit, such as lightness in weight is a
clear benefit for the automotive industry not only because it is
possible to reduce the total weight by reducing the consumption of
combustible, making systems and components more efficient, (Rivero
2018).
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
3
The versatility of polymers in their exceptional chemical, thermal,
optical, and mechanical qualities are linked to their chemical
composition and internal structure, which has allowed the creation of
specialty polymers, (Rivero 2018). In the automotive field many are
the polymers used for the development of its components or auto
parts and the selection of the same goes according to the application
or purpose to be fulfilled, we have the case of internal auto parts such
as vents that can be manufactured from polymers as mentioned in
(Majewski & Zawadzki 2013), Acrylonitrile-Butadiene-Styrene (ABS)
and ALPHA (ABS-Polycarbonate), for its good properties in terms of
rigidity, toughness, dimensional stability, resistance to chemicals and
good quality of surfaces, (Bhuvanesh Kumar & Sathiya 2021).
Additive Manufacturing (AM) is the significantly progressing field in
terms of methods, materials, and performance of fabricated parts.
Periodical evaluation on the understanding of AM processes and its
evolution is needed since the field is growing rapidly. To address this
requirement, this paper presents a detailed review of the Additive
Manufacturing (AM) methods, materials used, and challenges
associated with them. A critical review of the state of art materials in
the categories such as metals and alloys, polymers, ceramics, and
biomaterials are presented along with their applications, benefits, and
the problems associated with the formation of microstructures,
mechanical properties, and controlling process parameters. The
perspectives and the status of different materials on the fabrication of
thin-walled structures using AM techniques have also been discussed.
Additionally, the main challenges with AM techniques such as
inaccuracy, surface quality, reinforcement distribution, and other
common problems identified from the literature are presented. On
the whole, this paper provides a comprehensive outlook on AM
techniques, challenges, and future research directions, (Bhuvanesh
Kumar & Sathiya 2021).
Seeing these characteristics in properties that polymers have, the
automotive industry has looked for a new type of composite material,
(Rajak et al. 2019). This, combines matrix (plastic), reinforcing material
(fibers or particles) and additives), which forms a new material with
properties superior to the original ones, these materials are known as
composite materials (Chen et al. 2009; Mansor et al. 2013; Mansor et
al. 2014; Mansor et al. 2019; Ramesh 2019; Seldon y Abilash 2020).
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
4
Thus, one of the manufacturing processes used in the automotive
industry for work with polymers is the injection molding of
thermoplastics as mentioned in Hong, Kim, & Cho (2020) since it is
the only process that facilitates the mass production of products with
various geometries and good dimensional stability, so it is important
to consider the type of plastic injector machines that exist in the
country (Sin et al. 2012; Maghsoudi et al. 2017; Serban, Lamanna, &
Opran 2019).
The advantage of computational advances today has made it possible
to carry out simulations of injection processes to understand the
process before performing it (Ahmed Ali et al. 2015). For the present
study we will use a CAE simulation software to analyze the plastic
injection process with the selected materials (Henning et al. 2019). To
perform the simulation will be considered the type of meshing the
criterion used to perform the calculations, and variables such as the
fluidity of the polymer, the injection temperature, mold temperature,
etc. for the simulation by plastic injection (Hentati et al. 2019).
The multicriteria and weighting methods allow to obtain data from a
wide variety of candidates and obtain the best of them (Di Fratta et
al. 2020). Entropy tells us that entropy has a lot to do with the
uncertainty that exists in any experiment or random signal, standard
deviation is the separation that exists between any value of the series
and the mean (Deb 2021). Statistical variation is characterized by
intuiting the variations of the objects under analysis within a range of
interval or study variables, VIKOR and COPRAS (Martínez et al. 2018;
Parbat & Chakraborty 2021). The objective of this study is to obtain
an alternative material that can be obtained in the medium and
manufactured locally to replace the original ABS-PC material with
which the KIA RIO ventilation mask is manufactured so we will use
multi-criteria methods and simulations to obtain the ideal candidate
(Bhuvanesh Kumar & Sathiya 2021)
Methodology
In Latin America most of the vehicles that circulate are imported
and very few are assembled (Biggart & Guillén 2011). For this
reason, the polymer parts that are part of these vehicles are not
easy to obtain in the country and their costs increase, so three
alternatives of composite polymeric materials are analyzed to
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
5
replace the original and obtain the best of them. The first step
was to obtain the essential characteristics of the vent and
according to its requirements the characteristics are: good
rigidity, thermoplastic, impact resistance, mild aging, fluidity
index, injection mold processing, density, fluidity index and cost
(Mourtzis et al. 2019). Considering the above characteristics,
three candidates were selected to allow the manufacture of the
ventilation mask in Ecuador: 1) Polypropylene – Fiberglass, 2)
Polybutylene Terephthalate – 20% Fiberglass and 3)
Polypropylene – 20% Bamboo Fiber (MontavaJordà et al. 2019;
Rasana et al. 2019).
The standard deviation or standard deviation is a measure that
offers information about the mean dispersion of a variable. The
standard deviation is always greater than zero. To execute the
Standard Deviation method the following steps must be
performed:
First step: We build the decision matrix so we will use the matrix
developed for the Entropy method.
Second step: We calculate the standard deviation with equation
6:
!"#
$
!
!"#
$
"#$
!%
%$
%
&
&
'
(6)
Third step: We obtain the weights for criteria using the equation
7:
%"#
(
%
!
!"#
$
"(
%
(7)
Statistical variation method
This method is characterized by intuiting the variations of the
objects under analysis within a range of interval or study
variables, bearing in mind that the variation experienced by the
variable is subject to the value of the mean. This will allow us to
form a decision matrix that fits numerically and identify the result
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
6
that is closest to the ideal value, to execute the statistical
variation method, the following steps must be executed:
First step: For the development of the statistical variation
method, we apply the matrix of the entropy method using the
equation 8:
&
)*
#
$
!%
!
!"#
$
"+
!%
(8)
Second step: We normalize the matrix through equations 9 and
10:
&
)*
#
$
!%
+
!%
',$
(9)
&
)*
#
+
!%
')-
+
!%
"
(10)
Third step: We calculate the statistical variation using the
equation 11:
'
*
#
!
!"#
$
#.
!%
%.
%
&
&
!
!"#
$
"+
!%
(11)
Fourth step: We obtain the weights of the endpoints using the
equation 12:
(
*
#
/
%
!
!"#
$
/
%
"
(12)
VIKOR Method
In the VIKOR method the solutions must be defined separately,
for the positive ones they are evaluated with a maximum value
(100) and the negative values with a lower evaluation in the
system (0), is the algorithm proposed by VIKOR and the
following steps must be followed:
First step: We define the initial decision matrix using the one
performed in the Entropy method.
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
7
Second step: We normalize the decision matrix using the
equation 13:
)
)*
#
0
!%
1
!
!"#
$
,
&'
)*
(13)
'
*
#
*
)
22
)
23"
+
)
2-
)
22
)
33"
+
)
3-
,
)
'2
)
'3"
+
)
'-
-
Third step: the standardized matrix of weights was calculated
using the equations 14:
.#/()0
(14)
'
*
#
1
(
2
)
22
(
3
)
23
+
(
-
)
2-
(
2
)
32
(
3
)
33
+
(
-
)
3-
(
2
)
'2
(
3
)
'3
+
(
-
)
'-
2
Fourth step: the difference between positive and negative
values were calculated with the equations. 15 and 16:
345#567895:5;
)*
<"5=5>0?/7@A5:5;
)*
5<"5=5>5B50C5#
56;
2
"""',$
4
5;
3
"""',$
4
D?;
-
"""',$
C
(15)
3E5#56 7895:5;
)*
<"5=5>0?/7@A5:5;
)*
5<"5=5>5B50C5#
56;
2
"""',$
4
5;
3
"""',$
4
D?;
-
"""',$
C
(16)
Fifth step: the optimal solutions that will determine the value
range in each criterion were calculated using the equations 17,
18 and 19:
F
)
#G
)52
'
6
(
#7
%
'''$)*
%7
!%
&
#7
%
'''$)*
%7
%
'''$!+
&
(17)
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
8
H
)
#IJKL
M
6
(
#7
%
'''$)*
%7
!%
&
#7
%
'''$)*
%7
%
'''$!+
&
N
(18)
'
)
#
8#9
!
%9
$!+
&
#9
$)*
%9
$!+
&
O
#2%8&#:
#
%:
$!+
&
#:
$)*
%:
$!+
&
(19)
Sixth step: The results are positioned in an ascending way from
1 to 7, with 1 being the value closest to zero. This value close to
zero is the optimum in the VIKOR method.
COPRAS Method
This method allows us to find the best values that guide the
ideal results, applying the algorithm of the method is obtained
with the following steps:
First step: We develop the decision matrix for which we use the
normalized matrix of the VIKOR method.
Second step: the normalized decision matrix was defined by
applying the equation 20:
)
)*
#
,
!%
!
%"#
$
,
!%
(20)
H
)*
#
*
)
22
)
23
+
)
32
)
33
+
,
)
'2
)
'3
+
-
Third step: the standardized matrix of weights was carried out
using the equation 21:
'
)*
#/(
)
0/)
)*
0
(21)
'
)*
#
1
(
2
)
22
(
3
)
23
+
(
2
)
32
(
3
)
33
+
(
2
)
'2
(
3
)
'2
+
2
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
9
Fourth step: the normalized weights for each criterion were
obtained by applying the equations 22 and 23:
P
;)
#G
*52
'
5'
;)*
(22)
P
%)
#G
*52
'
5'
%)*
(23)
Fifth step: the performance index of each alternative was
calculated by applying the equation 24:
Q
)
#P
;)
O
!
%"#
$
<
,!
<
,!
"!
%"#
$
#
-,#
5
(24)
Sixth step: tiered performance was calculated using the
equation 25:
F
)
#
=
!
',$
4RSS
(25)
Seventh step: The highest value is considered the best option.
Results
Table 1 shows the candidate materials and the characteristics
with which the calculations of the weighting methods and multi-
criteria methods will be carried out, and the letters represent
the characteristics selected for the analysis of each material.
Table 1.
Criteria matrix
$ kg
1
Density
(Kgm
3
)
MFI
(gr
10min)
(Mpa)
EB (%)
Mod.
Elas.
(GPa)
F.
strength
(MPa)
IR (Kj
m
2
)
MT (°C)
A2
A3
A5
A6
A7
A8
1.15
19
60
23
80
0.587
1.42
13
6
4.4
138
71
1.46
16
6
3.4
78
37
1.00
18
4
3
138
50
Alternative Material for the plastic injection molding of the Kia Rio's ventilation grille
Revista Científica Interdisciplinaria Investigación y Saberes , / 2023/ , Vol. 13, No. 1
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The first line of result is ABS-PC material; second line is PP/
fiberglass (m1); third line is PBT / fiberglass (m2), and fourth line
is PP / bamboo fiber (m3).
Calculation of the Entropy Method
Table 2 shows the normalized decision matrix for the entropy
method according to equation 1 and the entropy values (ex),
criterion diversity (Dj) and weights Normalized (Wj) by equations
2, 4 and 5.
Table 2.
Normalized decision matrix
&:L
and values of ej, Dj, Wj
based on entropy method
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
0,2
0,3
0,2
0,5
0,3
0,4
0,3
0,4
0,2
0,4
0,5
0,3
0,3
0,2
0,3
0,3
0,2
0,2
0,4
0,1
0,1
0,2
0,3
0,1
0,3
0,2
0,2
0,3
0,2
0,4
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
Ej
0,8
0,9
0,9
0,9
0,9
0,9
0,9
0,9
0,9
0,938
Dj
0,137
0,012
0,008
0,082
0,015
0,012
0,058
0,032
0,014
0,062
Wj
0,31
0,027
0,019
0,184
0,034
0,027
0,132
0,074
0,032
0,143
Calculation of the Standard Deviation Method
For the development of the standard deviation method, we use
the matrix elaborated in the entropy method and using the
equation 6 the standard deviation (
TL
) of the values was
obtained as well as the weights of each criterion (
(L
) with the
use of equation 7 (Supplementary material).
Comparison of results of the Weighting Methods
In Table 3, we present the weights of each criterion for the three
weighting methods used, from this table we will use the values
obtained from the standard deviation method and the criteria
that will be entered for the analysis will be the density (A2),
creep index (A3) and glass transition temperature (A10).