Web based e manufacturing of prototypes by using rapid prototyping technology

INTERNATIONALMechanical Engineering and Technology (IJMET), ISSN 0976 –
International Journal of JOURNAL OF MECHANICAL ENGINEERING
6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME
AND TECHNOLOGY (IJMET)
ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 4, Issue 2, March - April (2013), pp. 32-38 IJMET
© IAEME: www.iaeme.com/ijmet.asp
Journal Impact Factor (2013): 5.7731 (Calculated by GISI)
www.jifactor.com ©IAEME

WEB BASED E- MANUFACTURING OF PROTOTYPES BY USING
RAPID PROTOTYPING TECHNOLOGY

Raju B S1, Chandra Sekhar U 2, Drakshayani D N 3
1
Associate Professor, Mechanical Engineering, Reva Institute of Technology and
Management, Yelahanka, Bangalore: 560064, Karnataka.
2
Scientist G, GTRE, C.V.Raman Nagar, DRDO, Bangalore: 560093
3
Professor, Mechanical Engineering, Sir.M.VIT, Bangalore, Karnataka.

ABSTRACT

There is an industrial need for rapid manufacture of one-off intricate prototypes, for
defense, vintage equipment and medical prosthetics. This paper presents a systematic
approach for this purpose, using a combination of reverse engineering, solid modeling, rapid
prototyping, rapid tooling and Internet technologies. Rapid prototyping and Manufacturing
technology, involves automated fabrication of intricate shapes using a layer-by-layer
principle, has matured over the last decade which posses high potential to reduce the cycle
time and cost of product development as one of the enabling tool in digital manufacturing.
Web based Rapid Prototyping & Manufacturing techniques enhances the design and
manufacturing productivity, speed, economy and reduction in lead time. Two basic
characteristics of RP make it eminently suited to web based e-manufacturing: (1) The main
input is a solid model of the part in a facetted format stored in a STL file (generated by 3D
scanning an existing part of by solid modeling) and (2) the fabrication process is highly
automated; no part-specific tooling is required. In practice, there are a large number of
combinations of RP and RT, besides a choice of materials and fabrication equipment. These
decisions greatly influence the quality of parts (in terms of surface finish, dimensional
accuracy, strength and life) as well as the lead time and cost. Thus the paper also presents the
experimental investigation to demonstrate the methodology and bench marking major RP/RT
methods to fabricate the prototypes for various applications such as functional testing,
Mechanical dynamic testing and patterns for casting.

Keywords: Solid modeling, E-Manufacturing, Rapid prototyping, Rapid tooling,
Internet based manufacturing

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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –

1. INTRODUCTION

Due to the advances in mechanical, electronics and computers components, there has been
significant growth in communication, information technology and worldwide networking, which
leads to globalization and opening of markets, hence increases in worldwide competition among
industries. The evolution of the market necessitated the reduction of time to market mainly
because the product life cycle is shorter but also because it is very important to proceed more
rapidly from an initial conception to mass production object [1].
Introducing new products at ever increasing rates is crucial for remaining successful in a
competitive global economy; decreasing product development cycle times and increasing product
complexity require new ways to realize innovative ideas. In response to these challenges, industry
and academia have invented a spectrum of technologies that help to develop new products and to
broaden the number of product alternatives. Examples of these technologies include feature-based
design, design for manufacturability analysis, simulation, computational prototyping, and virtual
and physical prototyping. Most designers agree that “getting physical fast” is critical in exploring
novel design concepts. The sooner designers experiment with new products, the faster they gain
inspiration for further design changes [2]
Rapid prototyping is the name given to a host of related technologies that are used to
fabricate physical objects directly from CAD data sources. These methods are unique in that they
add and bond materials in layers to form objects. Such techniques offer advantages compared to
classical subtractive fabrication methods such as milling or turning in following ways:

Objects can be formed with any geometric complexity or intricacy without the need for
elaborate machine setup or final assembly,
Objects can be made from multiple materials, or as composites, or materials can even be
varied in a controlled fashion at any location in an object,
Solid freeform fabrication systems reduce the construction of complex objects to a
manageable, straightforward, and relatively fast process.

Thus, the commercially available RP techniques are: SLA, SLS, FDM, 3DP, LOM, IJP and SGC.

2. RAPID PROTOTYPING & ITS SIGNIFICANCE

Introducing new products at ever increasing rates is crucial for remaining successful in a
competitive global economy; decreasing product development cycle times and increasing product
complexity require new ways to realize innovative ideas. In response to these challenges, industry
and academia have invented a spectrum of technologies that help to develop new products and to
broaden the number of product alternatives. Examples of these technologies include feature-based
design, design for manufacturability analysis, simulation, computational prototyping, and virtual
and physical prototyping. Most designers agree that “getting physical fast” is critical in exploring
novel design concepts. The sooner designers experiment with new products, the faster they gain
inspiration for further design changes [10]. The Rapid prototyping (RP) technology, involves
automated fabrication of geometrical shapes using a layer-by-layer principle from computer-
Aided-Design (CAD) data. “Rapid prototyping can be defined as solid free form production
through computer automated, layer manufacturing which allows the transformation of digital
design into 3D solid object for production of models, prototypes and tooling”. The figure 1
illustrates the methodology adopted for the rapid prototyping techniques.

33


Figure 1. RP Methodology

In the field of product development, particularly product modeling has become quite critical
in industrial performance improvement. The art of managing rapid product development
depends on making good trade-offs between four possible objectives in any product
development cycle.
* Development Speed
* Product cost
* Performance and
* Development program expense

2. RAPID DEVELOPMENT OF PROTOTYPES FOR CASTINGS

Development of prototypes/pattern for one-off intricate castings involves the
challenges of economic viability, quick tooling development and producing defect-free
casting at the first attempt. These challenges can be overcome by making use of RP process
for developing casting patterns for sand as well as investment casting. While RP may seem
slow, it is much faster than the weeks or months required to manufacture the tooling by
conventional machining processes, especially for complex shapes.
The RP processes can be used for directly producing the casting patterns, referred to as direct
rapid tooling. The RP parts can also be used as masters for ‘soft tooling’ processes such as
epoxy mass casting, PU face casting, metal spray and RTV moulding. Thus, the combination
of RP and soft tooling methods can give indirect routes for casting tooling development.
Example an FDM process(ABS-plastic master pattern), which converted into an epoxy mold
by mass casting and finally converted into a production pattern by PU face casting, Thus the
different RP techniques of each model and materials available for each RP and RT process
give a large number of potential routes. In recent era, several researchers have explored rapid
casting development using RP and RT. Casting produced by LOM patterns were found to be
around 25% cast saving [3] and LOM tooling yielding about 50% saving in time and cast
34


compared to aluminum tooling [4]. The various patterns produced for various applications
directly from FDM process about 73% less time compared to any other conventional methods
[5]. Stereolithography which is commonly known as master of RP systems which produces
epoxy resin prototypes were used in investment casting to produce foundry tooling and
castings, saving time up to 50% and proven with more cost effective than conventional
methods.
Today’s global environment can enable people to go “from Object to object” as
shown in fig 2 through 3D digitizing and reverse engineering. Part modeling and Rapid
manufacturing of parts, both directly and indirectly using rapid tooling. Knowledge and
know-how regarding new technologies should also be accessible for integration in the
product process during the design stage. In the course of Rapid product development, the
nature of data changes. Consequently, the numerical reference model should coherently
support different data formats, depending on the technologies and the design process stages.
The new technology initiative based on the STEP (Standard for Exchange of Product Model
Data) format which is used to define heterogeneous and multi-material object data
management [7].
There is an industrial need for rapid manufacture of one-off intricate prototype casting
for defense, vintage equipment and medical prosthetics. The RP and RT technologies provide
the solution, but are limited by the high costs of installation and maintenance. Thus this can
be overcome by using Web-based technologies, to create e-manufacturing systems. A number
of researchers have explored the application of Internet for engineering purposes. Most of
them have mainly focused on faster and effective communications and on virtual reality. IM
(Internet Manufacturing) proposed for the development of a distributed rapid prototyping
system via the internet to form a frame work of IM for the support of effective product
development [6]

3. E-MANUFACTUIRNG OF PROTOTYPES

Two basic characteristics of RP make it eminently suited to e-manufacturing: (1) the
main input is a solid model part in an STL file format which can be produced directly from
solid part or by reversing engineering techniques. (2) The fabrication process which is highly
automated without any specific tooling (TOOL LESS ADDITIVE PROCESS). Thus it is
possible to model the part or tooling in one location and get the part automatically fabricated
in another location by sending the data information of the model through the Internet facility.
The various step of casting pattern development can be compressed by web-enabling the PR
& RT route which is described below.
1. Switch on the server of the RP and forward the STL file of the pattern of the model to
the manufactured.
2. The STL file is checked and errors such as tessellation error, dangling edges and
missing facets if any, are fixed.
3. Thus the automatic generation of quotation depending on the pattern volume.
4. Once for all the acceptance of the customer is made, process planning is done
automatically for the part.
5. The part manufacturing is done on the RP machines, followed by post processing and
finally for dispatch.
6. The related invoice and forms are generated automatically and forwarded by e-mail &
then further forwarded for dispatch.
35


3.1 Illustration of Web Based Manufacturing
The figure 2 illustrates the web based manufacturing where the component can be
build anywhere in the world by using the internet facilities and also with available rapid
prototyping machine for fabrication. The figure 3 illustrates the architecture of web based
manufacturing of prototypes through rapid prototyping [9].

Prototype

Figure 2 Manufacturing through Internet web based Technique

Figure 3: Over all architecture - web based processing of prototypes through RP [9]

36


4. FABRICATION OF STEREOLITHOGRAPHY PROTOTYPES FOR MECHANICAL
CHARACTERIZATION

The mechanical properties of stereolithography (Photopolymer Parts) models can generally be
influenced by not only the material characteristics, but also the method of manufacturing. Since the
stereolithography process relies on the layer manufacturing concept as well as involves in the post-
curing process, it is possible for stereolithography model to exhibit the directional dependence
mechanical properties. The objectives of the present work focused on the influence of build
parameters such as Layer thickness, orientations, hatch space and the influence of ultraviolet post-
curing period to mechanical properties which are the most significant to the strength of
stereolithography product. The figure 4 – 6 illustrates the Tensile (D638-03), Impact (D 256-04) and
Flexural (D790) test specimen according to ASTM Standards with the stereolithography prototypes
which are used for mechanical characterization.

Figure 4: Tensile Test Specimen & SLA prototypes of Tensile test specimen

Figure 5: Impact Test Specimen & SLA prototypes of Impact test specimen

Figure 5: Flexural Test Specimen & SLA prototypes of Flexural test specimen

37


5. CONCLUSIONS

Pattern development is the main bottleneck (in terms of time and cost) for
manufacturing one-off intricate Prototypes, especially for replacement purposes. This can be
overcome by a combination of reverse engineering, RP/RT and web-based technologies as
illustrated above. The approach has been demonstrated by taking up a standard test specimen
which used to characterize the mechanical properties of stereolithography prototypes the
tensile, impact and flexural strength of CIBSTOOL SL5530 Resin produced by SLA5000
stereolithography machines through web based manufacturing process which drastically
reduces the lead time.

6. REFERENCES

[1] Raju, B. S., 2006, “New trends in Rapid product development”, International conference
on intelligent systems and control ISCO 2006, V.Gunaraj editor, Coimbatore, Tamil nadu, pp.
132-138.
[2] Krause, F. L., Ciesla, M., Stiel, Ch., and Ulbrich, A., 2000, “Enhanced RP for faster
product development processes”, Journal of Rapid prototyping, Vol 6, No2, pp. Page No: 63-
69
[3] Mueller, B., and Kochen, D., 1999, “Laminated object manufacturing for RP and
patternmaking in foundry industry”, Computers in Industry, no.1, pp.47-53.
[4] Wang, W., Conley, J .G, and Stoll, H.W., 1999, “Object Manufacturing Process”, Rapid
Prototyping Journal, Vol 3, pp: 134-141.
[5] Sushila, B., K. Karthik P.Radhakrishnan, 1998, “Rapid Tooling for casting- A case study
on application of Rapid Prototyping processes”, Indian Foundry Journal , Vol 11, PP: 213-
216.
[6] Francis, E. H. and Tay, 2001, “Distributed rapid prototyping- a framework for Internet
prototyping and manufacturing”, Journal of Integrated Manufacturing Systems, Vol 6, pp:
409-415.
[7] Raju, B.S., 2004, “Studies on application of Rapid prototyping for the generation of
photoelastic model”, M.Tech-thesis., Div.Mechanical Engineering, Sir M.VIT, Bangalore.
[8] Yasser, A., Hosni, Jamal Nayfeh, and Ravindra Sundaram, 1999,“Investment casting
using Stereolithography: Case of Complex objects”, Rapid prototyping Journal , Vol 5, No 1,
Page No1-7.
[9] Hongbo lan ., “Web based rapid prototyping and manufacturing system: A review”,
Computers in Industry, Vol 60 , Issue 9 , Dec 2009, Page 643-656.

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