Applications of virtual reality technologies in design and development of engineering products and processes/Vrtualios realybes technologiju taikymas kuriant ir vystant inzinerinius gaminius ir procesus.
Bargelis, A. ; Baltrusaitis, A.
1. Introduction
Virtual reality (VR) technologies support and accelerate product
design, facilitate actualisation and delivery of ideas, and are highly
helpful for discussions and collaboration [1]. It is known as a new
dimension in man-machine communication that combines real-time (3D)
computer graphics direct intuitive interaction in 3D space [2]. They are
one of the main mechanical engineering tools helping to obtain better
results designing new and improving already designed products [3, 4].
Significant benefits on efficiency and flexibility of processes as well
as functionally of products serve as the reference point for using such
technologies in other engineering operations [5, 6]. Short production
terms, often being the case even manufacturing complex products, make
manufacturers to involve engineers of various specialisations. In such
situations, quick, creative, and integrated activities are needed in
order to find and integrate efficient solutions. The use of virtual
technologies in various product design or manufacturing stages requires
various abilities and skills, such as the understanding of what is
requested, using computer and software, converting and processing data,
understandable presentation of the information; also insight,
experience, curiosity, and talent. The better the engineer at each stage
of the chain understands what is requested from him/her and the more
understandably he/she delivers his/her requests, the smother the
following stages of product design go. This is also applicable to the
ability of collecting data that later will be used for designing virtual
3D prototypes and further development of the products; and skills of
creating and improving virtual 3D prototypes that later will be used for
designing CNC and other programs and preparing questions and proposals.
The most important aspects of the application of VR technologies [7, 8]
discussed in the article:
Novelties: the article describes the method which allows
accelerating many stages of product design, development, and
manufacturing; putting into effect solutions that can hardly be
actualised using classical methods. This method originated from multiple
attempts to use VR technologies in the area of products design and
develop in Mechanical Engineering Company; the result was achieved due
to contact development of mechanical processing technologies, tight
collaboration supported by an IDEF0 diagram of corporate specialists and
divisions, and good-willed cooperation between the manufacturer and the
client [9].
Scientific value: cross-disciplinary communication enables
developing new information, transferring and accepting knowledge and
experience, acquiring and improving skills, accumulating experience and
so on. Practical value: improved technical communication and more rapid
generation of alternative ideas. Designing spherical elements and
implementing them into the existing 2D drawings is complicated and time
consuming process. It requires the creation of additional technologies
that extend the time and increase the cost of production. Besides this,
the 2D technology requires using several reference points that influence
manifestation of setting (measurement) errors.
2. The improvement of technological process using VR
2.1. The relationship between physical and virtual prototypes
The usability of the user interface is a key aspect for the success
of several industrial products. This assumption has led to the
introduction of numerous design methodologies addressed to evaluate the
user-friendliness of industrial products. Most of these methodologies
follow the participatory design approach to involve the user in the
design process [10]. 3D prototypes may be successfully used in various
stages of product design and manufacturing: rapid design and improvement
of work pieces; rapid design and improvement of surface geometry and
preciseness; rapid generation of alternatives that would improve the
structure and workability of the part or product; better cooperation
between the manufacturer and the customers, the manufacturer and the
consumers, and between various departments of the manufacturer. Virtual
3D prototype may be improved at any time by using software. The
technological solution is implemented into a product at early production
or design stages. The improved prototype is transferred to the
programmer, who creates CNC program for mechanical processing of the
product. Surface and geometry of the product remain unchanged, but
there's achieved enhanced workability of the product. Simpler
processing technology and reduced technological tooling reduce
mechanical processing time thus enabling manufacturers to offer
customers more competitive prices.
In a proposed case the manufacturer obtained primary 3D prototype
from the customer (Fig. 1). It was a welded structure consisting of
various length square tubes with wall thickness 3mm and plates of
different geometrical forms and sizes. The plates were located at
various original and complicated angles facing each other. Most of them
should be mechanically processed aiming to obtain surfaces and holes of
certain preciseness (tolerance T, Table 1). The development of the
product, using VR technology, consists of the following stages:
* the evaluation of geometrical, constructional and mechanical
processing possibilities of the product;
* development stage;
* creation of the CNC numerical control program. The examination of
3D prototype is presented on the monitor. Making decision on the
improvement of the prototype is proposed, aiming to improve workability
of the product. Such improvement enables to maintain customers'
requirements after implemented changes. Deciding on what actions shall
be taken in order to implement the idea and performing them. Choosing
necessary 3D and 2D CAD software and measurement tools for the
implementation of idea is discussed.
[FIGURE 1 OMITTED]
2.2. Digitization of physical model
This method was necessary since CNC machine was capable of
processing elements not larger than overall dimensions 1700x1000x350 mm.
Sometimes the manufacturers get orders exceeding the capabilities of CNC
machines. In such case inquiry or even order must be cancelled facing
technical capabilities of the manufacturer. Cancelation of inquiries and
orders may to lead for losing customers. In order to retain
competitiveness manufacturer must put in one's best efforts as
possible performing gotten orders. In the described case, the overall
dimensions of the product were 2100x1400x206 mm. Such welded structure
is processed applying tool machine with bigger work table but less
possibility of spindle positioning the tilting and turning in respect to
coordinate system of machined welded structure. In such cases,
manufacturers used to produce specific technological tooling that served
as a starting point or a compensation of tilting or turning of the
element or spindle. The production of such technological tooling
required additional time, machinery, high quality specialists,
materials, and energy. In addition, such technological tooling might not
be enough for establishing one reference point and machining the welded
structure because the manufacturers must use several reference points
making more complicated chain of measurements and increasing the
probability of setting errors. Designer's input to the improvement
of the product depends on his/her knowledge of manufacturing technology
and design skills. In a development stage, the main designer' s
output is an alternative 3D prototype. Virtual 3D prototype of the
product becomes the intermediary between the customer, the designer, the
technologist, and the operator. The described method has been developed
aiming to improve mechanical processing technology, saving expenses of
producing additional technological facility, and reducing the number of
actual production actions and the number of reference points thus
avoiding the errors. Product development diagram, generalising the
applied method, is delivered in (Fig. 2.)
[FIGURE 2 OMITTED]
Aiming to improve the workability of the product, spherical
element, delivered in (Fig. 3), was used. That tooling is fixed in a
rectangular tube. As technological fixing feature for spherical element
a M6 3 mm depth hole is used. Spherical elements perform significant
roles in manufacturing of the products with prevailing precise and
geometrically intrinsically to each other located surfaces. This element
combines its mechanical functions with the idea of a technologist
improving the workability of the product and creating better
opportunities to design CNC program for manufacturing of the product
reducing the amount of technological tooling and the probability of
setting (measurement) errors. Aiming to develop 3D prototype delivered
by the customer to the level that satisfies the requirements of a
production technologist and programmer, the designer created virtual 3D
prototype of a spherical element (Fig. 4).
Virtual 3D CAD prototype of the spherical element has been created
on a basis of the sketch in communication with 3D design program (Fig.
5). Data for the sketch Table 2 was obtained having measured physical
model of the spherical element in a measurement laboratory. The process
of developing a 3D prototype of the spherical element had to involve a
specialist of measurement laboratory who had to measure physical model
of the spherical element and design the sketch with required dimensions.
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
[FIGURE 5 OMITTED]
[FIGURE 6 OMITTED]
Virtual 3D spherical element was integrated in a VR into virtual 3D
model, sent by the customer, making an additional M6 3 mm deph hole. The
location of the technological feature was selected by the programmer
emploing his/her knowlewdge on the manufacturing technology and
properties of the machinery that will be used for mechnical processing
of the developed product. The sketch with required dimensions was
delivered to the designer (Fig. 6). The sketch involved the indication
of the type and the location of the hole in a primary model of the
product. Then the designer emploing his design skills integrated the
hole to the virtual 3D prototype (Fig. 7).
[FIGURE 7 OMITTED]
After the improvement of virtual 3D prototype, integrating an
additional spheric element (Fig. 8), new projections of the product in
2D environment were made. This data was used for the developmdent of CNC
program to produce an actual product (Fig. 9).
[FIGURE 8 OMITTED]
[FIGURE 9 OMITTED]
3. Conclusions
In response to scientific value: possibility of facing, designing,
and integrating virtual prototypes is a good basis for firming already
possessed and acquiring new, specific, knowledge on the implementation
of virtual prototypes in the area of product design and manufacturing.
Such experience also helps to maintain and improve one's
innovative, adaptive, and competitive potential.
In response to practical value: the integration of VR technologies
enhances the possibilities of manufacturers to implement various
technological solutions and make this process faster. It helps to
transfer the knowledge acquired into the processes and products as well
as provides better opportunities for using the information collected at
early stages of product or process development.
Novelties: the applied method connects classical and VR
technologies. The use of VR technologies accelerated the integration of
a spherical element into a 3D prototype and the preparation of CNC
program.
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Received November 02, 2012
Accepted August 21, 2013
A. Bargelis *, A. Baltrusaitis **
* Kaunas University of Technology, Kestucio str. 27, Kaunas,
Lithuania, E-mail: algirdas.bargelis@ktu.lt ** Kaunas University of
Technology, Kestucio str. 27, Kaunas, Lithuania, E-mail:
alfredas.baltrusaitis@stud.ktu.lt
cross ref http://dx.doi.org/10.5755/j01.mech.19.4.5057
TABLE 1
Geometrical and mechanical characteristics of the product
Element Position of the element in
rectangular coordinate
system
[empty set]6H7 [perpendicular to] / [parallel]
[empty set]8H7 [perpendicular to] / [parallel]
[empty set]10H7 [perpendicular to] / [parallel]
M8 [perpendicular to] / [parallel]
M10 [perpendicular to] / [parallel]
M12 [perpendicular to] / [parallel]
Milling [perpendicular to] / [parallel]
surface [R.sub.a]3.2
Milling [angle]10[degrees] / [perpendicular to]
surface [R.sub.a]3.2
Milling [angle]22[degrees] / [angle]80[degrees]
surface [R.sub.a]3.2
Milling [angle]82[degrees] / [angle]89[degrees]
surface [R.sub.a]3.2
Milling [angle]55[degrees] / [perpendicular to]
surface [R.sub.a]3.2
Element T
[empty set]6H7 +0.015
0
[empty set]8H7 +0.015
0
[empty set]10H7 +0.018
0
M8 [+ or -] 0.2
M10 [+ or -] 0.2
M12 [+ or -] 0.2
Milling [+ or -] 0.2
surface [R.sub.a]3.2
Milling [+ or -] 30" /[+ or -] 0.1
surface [R.sub.a]3.2
Milling [+ or -] 30" /[+ or -] 0.1
surface [R.sub.a]3.2
Milling [+ or -] 30" /[+ or -] 0.1
surface [R.sub.a]3.2
Milling [+ or -] 30" /[+ or -] 0.1
surface [R.sub.a]3.2
Element Mechanical operations
[empty set]6H7 centering, drilling,
reaming, broaching
[empty set]8H7 centering, drilling,
reaming, broaching
[empty set]10H7 centering, drilling,
reaming, broaching
M8 centering, drilling,
tapping
M10 centering, drilling,
tapping
M12 centering, drilling,
tapping
Milling Rought milling, smooth
surface [R.sub.a]3.2 milling
Milling Rought milling, smooth
surface [R.sub.a]3.2 milling
Milling Rought milling, smooth
surface [R.sub.a]3.2 milling
Milling Rought milling, smooth
surface [R.sub.a]3.2 milling
Milling Rought milling, smooth
surface [R.sub.a]3.2 milling
TABLE 2
Data for integration of spherical element into primary product
Element Length T Width W, Diameter D,
L, mm mm mm
Sphere 125.45 [+ or -] 0.2 - 30
Hole 3 [+ or -] 0.2 - M6
Element T Coord. x, T Coord. y,
mm mm
Sphere [+ or -] 0.02 (442) [+ or -] 0.2 40
Hole [+ or -] 0.2 (442) [+ or -] 0.2 40
Element T
Sphere [+ or -] 0.2
Hole [+ or -] 0.2
