JOURNAL OF INDUSTRIAL DESIGN AND ENGINEERING GRAPHICS 41 [619122]

JOURNAL OF INDUSTRIAL DESIGN AND ENGINEERING GRAPHICS 41

Abstract: Electric cars for children may seem dangerous to some, but they are quite safe compared to other
toys. They are made of non -toxic materials, which have good impact resistance and are lightweight. Due to
the manufacturing processes, their components are not small and cannot endanger children. The main
objective of the paper is to study the optimal orientation of the construction of a children's car from ABS
material processed by injection molding.
Keywords: toys, safety, analysis, 3D model, improvement , simulation.
1. INTRODUCTION
Plastic toy cars are part of the light industry. The
light industry usually requires less capital than heavy
industry and is more consumer -oriented than
enterprise -oriented. Light industry installations do
not have too great an impact on the environment
compared to those associated with heavy industry.
The plastic used to make the largest components, for
example, the body and the seat, which make up a
large part of the structure of toy cars are made of
polyethylene (PE) and polymers derived fr om
styrene, especially acrylonitrile butadiene styrene
(ABS).
They are used in the manufacture of toy car
components due to their most interesting properties,
which surpass in applications many other
thermoplastic materials, such as their resistance,
supe rior impact even at low temperatures, excellent
stretching behavior, chemical resistance high and
very low weight of the finished products.
The shape of the products depends mainly on the
chosen training technique. Vacuum formed products
can be identified by models that have an internal and
an external shape, but which follow the same shape.
Injection molding is used for solid components in a
toy car where the parts require different internal and
external shapes.
Components made using this technique may also
have attachment points. An injection molding
machine is a combination of three machines: the
laminatin g and injection machine, the press, and the
mold. Injection molding is the most important
commercial method for transforming thermoplastics
into useful products. A thermoplastic polymer can be
reheated and remodeled many times. During the
injection molding process, the plastics are heated until they reach a fluid state. The molten plastic is
then injected under high pressure through a nozzle
into a cold mold . The plastic takes the shape of a
mold while its temperature drops enough to be quite
hard. After th e plastic has cooled, the mold opens,
and the product is released from the mold .
Most of the time the final result, ie the finished
product is no longer needed retouching. The parts
made by this process have one or more of the
following characteristics: l ateral parting lines or
glued portions created by the two parts of the mold ,
sharp corners, fine and precise details. Blow molding
technology has been adapted from the glass industry
to model empty containers made of thermoplastic
materials. The most famou s objects cast by blowing
are bottles, jars, etc. Other blow -mold ed objects
include toy car wheels.
Working principle:
• Power supply: This is necessary to supply
power to the entire operation and to allow all
parts to operate. In a remote -control car, the
power supply is the battery.
• Engine: The engine is the one that fulfills
everything moving all necessary parts and
performing the basic function, including
turning the wheels, steering, and applying
acceleration or braking.
• Transmitter: The tran smitter acts as a remote
control and is the thing you hold in your
hands and with its help and radio waves you
can dictate the commands of the toy car.
• Receiver: This is locating in the RC machine
and has an antenna and circuit board that
allows it to rece ive signals that the
transmitter sends and move the necessary
parts . VERONICA -ANDREEA RADULESCU
CONSIDERATIONS ABOUT SAFETY AND EFFICACY IN THE FIELD OF
DESIGNING CHILDREN'S CARS

ABOUT DESIGN, SAFETY, AND PRAGMATISM IN THE FIELD OF CHILDREN'S CARS

VOLUME 7  ISSUE 1 JUNE 2012 42 Although not accepted by any recycling
machine/installation, ABS is part of the category of
plastics that can be recycled only once.
ABS is one of the many types of thermoplastic
and with applications in other fields such as
biomedical; thus, injection molded components are
the easiest to manufacture for a single -use. The main
method of sterilizing ABS is performed using
gamma radiation , or ethylene oxide ( ETO ).
2. THE NEW MODEL
In this chapter of the paper, I will talk more about
my ideas, methods, and contribution concerning the
improvement elements of children's toy cars. The
model I will talk about below is designed for a child
aged between a minimum of 4 and a maximum of 6
years. Thi s model is designed based on a list of
requirements (tab le 1).
The design of a product involves a set of activities
and processes that allow the transition from the idea
of a new product /an existing product (or improving
an existing product) to information (drawings,
programs, etc.) that permit the launch in production
and exploitation of the product.

Table 1 – List of necessity
The 3D model was made in CATIA
3DExperience (the latest version of catia software).
This model can be made from the materials we
presented in the previous paper, where we talked at length about the multitude of plastics and different
manufacturing technologies of these materials with
an application, especially on children's to y cars.

Figure 1 – Isometric view
The seat has a high back to avoid hitting the head
or unbalancing, these being the consequences of a
sudden departure from the place. The seat has a high
back to avoid hitting the head or unbal ancing, these
being the consequences of a sudden departure from
the place. It can be seen in figure 2, side view, that
the seat is positioned so that the position in which the
child sits is a natural one.

Figure 2 – Lateral vis ion
The windshield is small, positioned low enough
to allow the child driving the car to observe the
territory and objects around it.

Figure 3 – Front view
The car does not have doors that open or close
because they can be a danger to the child from
several points of view such as holding the hand in the
door or hinge. Also, the car does not have a sharp
Requirements list
No. Needs
1 Safety
2 Ergonomics
3 Easy to handle
4 Powerful battery
5 Adjustable speed
6 Have different accessories /
interactive buttons, with sounds and lights
7 Be colorful
8 Easy to use both indoors and outdoors
9 Durable material
10 Do not have small parts
11 Cheap
12 Easy to transport
13 Double control (with remote control)
14 Comfortable
15 Silent

JOURNAL OF INDUSTRIAL DESIGN AND ENGINEERING GRAPHICS 43 edge, because they also have a risk of injury. The
width of the car is 70 centimeters , the width of 125,
and the height of 55 these dimensions within the
safety standards, which provide for the overturning
of the car. The car is equipped with a green ON / OFF
button, to start or stop the current in the car's
electrical circuit (figure 5), the accelerator pedal, and
two handles for adjusting the seat (figure 6), which
moves the seat up / down and front/rear. These
buttons for adjusting the seat are essential from an
ergonomic point of view. The position that the child
adopts while driving the car must be a natural one,
which does not bother him and makes him feel
comfortable and safe.

Figure 4 – Interior view

Figure 5 – Interior view (adjustment levers)
3. TESTI NG AND MECHANICAL
PROPERTIES
The design of a product involves a set of activities
and processes that allow the transition from the idea
of a new product (or improving an existing product)
to information (drawings, programs, etc.) that permit
the launch in production and exploitation of the
product.
After making this model I chose the material from
which it should be made. As I said in the previous
paper, most of the toys are made of plastic. I also
argued why the plastic most frequently used by large companies producing children's cars is chosen as
ABS material. Its properties are among the most
suitable, in terms of resistance to pressure, traction,
twisting, and shock.
To predict the performa nce of the prototype in the
real world and because the safety is given by the
resistance of the components to demands,
consequently we simulated on the 3D model the
behavior of the product at different loads at the
estimated average weight of a child.

Figure 6 – Isometric view simulation
The figure above (fig. 6) shows the static
structural analysis of the baby car made of plastic,
ABS, and built by an injection molding technique.
The equivalent stress is maximum in the central
region of the seat of the car and is due to the sudden
change of the cross -section near the length of the seat
which leads to a high concentration of stress, as
shown in figure 7.

Figure 7 – Interior view simulation

Figure 8 – The results of the tensile strength test for the car

ABOUT DESIGN, SAFETY, AND PRAGMATISM IN THE FIELD OF CHILDREN'S CARS

VOLUME 7  ISSUE 1 JUNE 2012 44

Typical Mechanical Properties of ABS
Property Value
Young's Modulus (GPa) 2,28
Tensile Strength (MPa) 43
Flexural modulus (GPa) 2,48
Flexural Strength (MPa) 77
Notched Izod (kJ/m) 0,203
Heat Deflection Temperature, 1.81 MPa,
(C) 81
Emission factors CO2 (kg) 3,46
Table 2 – Typical Mechanical Properties of ABS
The maximum value of the equivalent stress
obtained after the simulation is 0.7485 MPa, this
being below the value dictated by the properties of
the chosen material (ABS), whose tensile stress has
the value 43 MPa, or the breaking stress of 77 MPa.
Thus, the piece withstands very well an average
weight of about 30 kg , of a child.
4. CONCLUSIONS
In this paper, the tensile strength of a children's
car was measured. The parts were tested for tension
and the results were compared with the nominal
values of the strength of the ABS plastic.
The purpose of this paper was to determine the
mechanical strength of children's car parts,
comparing them with the mechanical properties of
the nominal material. This information is needed to
know how to design functional parts with this
technology, whose use is growing more nowadays.
The experimental result showed that the product
made of ABS by injection molding has tensile
strength. The stress distribution was investigated
using the INVENTOR 2021 workbench the
maximum developed stress is in the edges of the seat
component due to the su dden change of the cross –
section which leads to a high concentration of stress,
as shown in the figure. The total deformation, the
equivalent stress, and the maximum principal stress
and the results were obtained as shown in the figures
below.
As expected , the maximum tensile strength
produced by the 3D model is lower than the nominal
strength of the material.
From a future perspective, I want to make a 3 D
model for a frame for extra protection and safety in
case of overturning. 5. REFERENCES

[1] https://www.res earchgate.net/publication/32
6965385 T
hermoplastic_polymers_in_product_desig n
[2] https://www.researchgate.net/publication/32
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Thermoplastic_polymers_in_product_desig
n
[3] https://www.academia.edu/33553537/Curs_
de_tehnologie_injectie_mase_plastice
[4] http://injectieplastic.blogspot.com/2014/09/
acrilonitri butadien -stiren -abs.html
[5] https://www.researchgate.net/publication/28
3498079_Experimental_Determination_of_
the_Tensile_Strength_of_Fused_Deposition
_Modeling_Parts
[6] https://www.ijirset.com/upload/2018/june/4
0_Tensile.pdf
[7] http://old.unitbv.ro/Portals/45/Admitere/Ma
ster/6%20Marascu -Klein.pdf
[8] https://dielectricmfg.com/knowledge –
base/abs/
[9] https://en.wikipedia.org/wiki/Acrylonitrile_
butadiene_styrene
[10] http://www.matweb.com/search/DataShee
t.aspx?MatGUID=3a8afcddac864d4b8f58d
40570d2e5aa&ckck=1

Author:
Veronica Rădulescu, Faculty of Aerospace
Engineering.
Coordinator: Assoc. Prof. Dr. Daniel Dobre
The Polytechnic University of Bucharest,
Department of Engineering Graphics and Industrial
Design, Faculty of Aerospace Engineering.