Recent trends in rapid product development 2-3-4

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Recent trends in rapid product development 2-3-4

  1. 1. 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. 21-31 IJMET© IAEME: www.iaeme.com/ijmet.aspJournal Impact Factor (2013): 5.7731 (Calculated by GISI)www.jifactor.com ©IAEME RECENT TRENDS IN RAPID PRODUCT DEVELOPMENT Raju B S 1, Chandra Sekhar U 2, Drakshayani D N 3, Chockalingam K 4 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. 4 Professor, Mechanical Engineering, TCE, Madurai, Tamil nadu. ABSTRACT The paper presents an overview of new approaches in rapid product development from the design point of view. 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 and also because it is very important to proceed more rapidly from an initial conception to mass production object. In product development, Rapid Prototyping has turned out to be the instrument to save time and money and also develop innovative products. RP has evolved as a frontier and emerging technology in which every individual can see the goal, the product and can relate to the customer, which tremendously reduces the lead-time to produce physical prototypes. RP is useful in the fast production of physicals prototypes and therefore constitutes a key element in the optimization and abbreviation of product development processes. Thus the paper gives the information, that how the product development time can be reduced by using RP with an aid of gas turbine engine component as an intended study , which aims to emphasize as time compression engineering. Key Words: Rapid prototyping, Time compression Engineering, Lead time, Rapid Product development, Centralizing spring. 21
  2. 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME1. INTRODUCTION The field of product development, particularly product modeling [1], has becomequite critical in industrial performance improvement. The art of managing rapid productdevelopment depends on making good tradeoffs between four possible objectives in anyproduct development cycle: (a) development speed, (b) Product cost, (c) productperformance, and (d) development program expenses. Prior to the 1980s, product cost &performance were the dominating factors. During 1980’s, quality became the focal point,with the proliferation of techniques such as SQC, TQM, the Taguchi method and the Kaizenmethod [13]. Since the 1990’s, the emphasis has shifted to the time-to-market race in order tosurvive and compete in the global competitive market. This shift in emphasis, of course,should not be at the expense of performance, cost, quality and reliability. Indeed, when all themajor players in the field are able to satisfy all the above criteria, a new competitive &cutting edge strategy should appear, comprised of tools and techniques for rapid productdevelopment (RPD).2. RAPID PROTOTYPING & ITS SIGNIFICANCE Introducing new products at ever increasing rates is crucial for remaining successfulin a competitive global economy; decreasing product development cycle times and increasingproduct complexity require new ways to realize innovative ideas. In response to thesechallenges, industry and academia have invented a spectrum of technologies that help todevelop new products and to broaden the number of product alternatives. Examples of thesetechnologies 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 designersexperiment with new products, the faster they gain inspiration for further design changes [2]. Rapid prototyping (RP) refers to a class of technologies that can produce physicalobjects directly from 3D CAD or other 3D data sources. RP is characterised by an ‘additive’or ‘layer-by-layer’ approach due to which it is also called as layered manufacturing. Uses ofRP models cover the wide range of fit, form and functional activities in a variety of industriesconsisting of but not limited to aeronautical, automotive, biomedical, consumer goods,foundry, electronics, MEMS, space research and tooling industries [3]. The firstcommercially packaged RP technique ‘Stereolithography’ [4] was launched by 3D Systems,USA during 1986 and since then different RP techniques such as FDM, laser sintering, 3Dprinting, laminated object manufacturing, solid ground curing, laser engineered net shaping(LENS), electron beam melting etc., have become commercially available. These RP systemsproduce parts in a variety of materials including thermoplastics, laminated paper, starchpowder, polymer wax, metals, alloys and composites. Ceramics [5] with unique mechanicaland electrical properties have also been successfully inducted into RP process. 3D printingsystems developed by Z Corp, USA have led a revolution in RP industry by virtue of theirprolific applications in industrial design activities. These systems prepare prototypes in starchlike materials in a wide array of colors. LENS system produced by Optomec, USA facilitatesproduction of parts in a range of engineering materials including titanium and nickel basedsuper alloys [4] which in turn led to the induction of RP in repair and refurbishment of gasturbine engine components. Combined use of reverse engineering and RP tooling has beenattempted in producing limited series castings from worn out parts [6]. 22
  3. 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME The RP technology is increasingly being used to accelerate the preparation ofprototypes. The figure 1 Calls for the acceleration of all tasks required for the creation ofprototypes. Figure 1. Acceleration Potentials through use of CAD & RP2.1. Rapid Prototyping Process Chains for Product Development. Prototypes for product development can be differentiated into design, functional andtechnical prototypes [10]. Design prototypes are used for verification of haptic, aesthetic anddimensional requirements, for functional verification and optimization, functional prototypesare required during product design. Technical prototypes are produced using the productionmaterial and where possible by means of the actual production process [3]. In general, RP process chain in product development comprises the elements asshown in fig 2 are process planning, production, quality inspection, digitization and geometrymodifications. For the continuous and uninterrupted support of RP process chains, an RPtoolkit has been developed comprising components for the following process steps as shownin fig 2a. • Modeling of virtual products • Data exchange and model preparation • Technological planning and • Reverse engineering.The rest of components enable the required information – technological linkage of individualcomponents for the implementation of a STEP based integration. [2]. For the modeling ofvirtual products, systems were developed for styling and feature based design. The stylingprocess is supported using the virtual cal modeling approach based on Voxell modeler. TheVCM (Virtual Clay Modeling) system developed is an adequate tool for design conception,enabling the provision of the conceived shape base on 3D model data representation at beingof the entire process. The VCM system is based on a modeling kernel, which oriented aroundthe real counter parts in the model building and which provides computer internal tools suchas scrapers, templates and true sweeps for the manipulation or editing of computer-internaldesign models. The components for model preparation provide for automatic error detectionand repair of surface and facetted models. The measurement planning component is used for 23
  4. 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEMEplanning of inspection and digitization processes on coordinate measurement machines,which comprises the determination of measurement operations, definition of measurementstrategies, selection and configuration of measurements probes and N/C path generation [2].For the support of reverse engineering, concepts related to Voxel and feature based localshape modification are under development. For Voxel based capture and update, the modifiedwork piece area is first digitized. The set of points captured is converted into a Voxelrepresentation and the original prototype adapted using a best fit procedure. Using themeasurement planning components for CMM, digitization strategies are assigned to themodified features that make it possible to determine the current feature parameters based on asmall number of measurement points.2.2. Rapid Product Development Process Today’s global environment can enable people to go “from Object to object” asshown in fig 3 through 3D digitizing and reverse engineering. Part modeling and Rapidmanufacturing of parts, both directly and indirectly using rapid tooling. Knowledge andknow-how regarding new technologies should also be accessible for integration in theproduct process during the design stage. In the course of Rapid product development, thenature of data changes. Consequently, the numerical reference model should coherentlysupport 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 ModelData) format which is used to define heterogeneous and multi-material object datamanagement [7]. Figure.2. Integration of Rapid prototyping into product development3. STEREOLITHOGRAPHY PROCESS For initiating the Stereolithography process, the CAD model of the desired object is tobe created. Though water-tight surface models can be acceptable, the most preferred fileinput is the 3D CAD solid model. Interface between the CAD model and Stereolithographysystem is the STL file (tessellated file format). The slicing phase follows the STL file 24
  5. 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEMEgeneration and in this phase, the input file is mathematically sliced into a series of horizontalplanes through special software. The result is the SLI file that represents a series of closelyspaced two-dimensional cross-sections of the three-dimensional object, each at a slightlydifferent Z coordinate value. The most important build parameter that is frozen in the slicingphase is the layer thickness. On the SLA 5000 system, layer thickness can be fixed betweenthe limits of 50 and 250 µm. The models used in the present research are built with 100micron thickness layers [8]. Before initiating the build process, supports are created forholding the layers during the build process and also securing isolated segments. Throughoutthe part building phase, galvanometer-driven micro mirrors receive commands from theprocess computer and direct the laser beam downward onto the free surface of the liquidphotopolymer. The short wavelength of the UV radiation and the weak focusing employed,result in sufficient focus depth to provide acceptable beam diameter over the entire surface ofthe photopolymer. During the scanning phase, the laser beam firstly traces the boundaries ofthe particular cross-section and subsequently solidifies the internal areas through hatching.The system automatically adjusts the laser exposure to ensure that the border and hatchvectors are cured to adequate depth that in turn facilitates adhering of the current layer to thepreviously formed layer. The process continues without any human intervention until theentire physical object has been generated. After the completion of the build process, theplatform along with part and supports is transferred to a cleaning station. [14]. Figure 2a. Integration of Rapid prototyping into product development Uncured residual liquid resin is cleaned off the part with a solvent like acetone or isopropylalcohol. Supports are removed with due care as to avoid damage to the down facing surfaces. 25
  6. 6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEMEThe object in this condition is said to be in ‘green’ state as a small amount of uncured resinstill remains trapped among the hatch lines. The cleaned object is placed in a post cureapparatus (PCA), where it is flooded with ultraviolet radiation of an appropriate wavelengthto complete the curing. After post curing, the object may be subjected to a variety of finishingsteps such as glass bead blasting, sanding, milling, drilling, tapping, polishing, painting,electroplating, etc for further improvement in surface quality or functionality [9]. If the partsize is bigger than the build envelope of a Stereolithography system, the part can be built in amodular manner and bonded with epoxy resin to form the assembly as shown in the fig 4.But the Size limitation is up to 500mm X 500mm X 500mm, if the prototypes are Larger sizethen the parts builds with different sections and then it will be glued to get the prototype. Figure 3. Rapid product development process 26
  7. 7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME Figure 4. Schematic of Stereolithography process4. MANUFACTURING OF A ROTOR BRACKET THOROUGH STEREOLITHOGRAPHY(CASE STUDY -I) The rotor damper bracket (fig 5) of a gas turbine engine performs very crucial role inensuring appropriate rotor dynamic performance of the fan module. Stringent stiffnessrequirements, assembly limitation and weight restrictions render the process of designing thebracket very challenging with inevitable iterative studies. The regular method ofmanufacturing an epoxy bracket model consists of the fabrication of a metallic masterpattern, silicone rubber moulding (fig 6) and casting with room temperature setting epoxyresins. These labor-intensive procedures consume about 25 days to prepare every damperbracket model. In conventional scenario, manufacturing of each new candidate design entailsmanufacturing of new pattern and subsequent silicone rubber moulding. The optimization ofrotor bracket involves studying of 6 to 8 design, which in turn extends the manufacturingcycle time to about 150 days. The present study uses Stereolithography (Building parameters:Layer thickness -0.01mm , HX –orientation, Post curing time- 60 min , Hatch spacingbetween layers – 0.0015mm) though which a similar model is produced from the CAD datain just 3 days (fig 7). Different design options of the rotor bracket that have modified valuesof axial web length, number of slots and radial thickness of the web are made through CADdata modifications. It takes less than 30days to manufacture the full range of the models thatincorporate all the intended design changes. Effective time saving s in this case study is about120 days and this ensures competitiveness of experimental procedures vis-à-vis analyticalmethods. 27
  8. 8. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME Figure 5. CAD Model of Rotor Bracket (Centralizing Spring) Figure 6. Master pattern and silicone rubber moulds Figure 7. Prototype pattern used for conventional manufacture of rotor bracket. produced by SLAHence conventional machining procedures are fraught with several debilitating features thatprolong the manufacturing time frame to as high [table1].The present works uses amethodology which is totally devoid of tooling, casting and residual stress related problemsthat in turn leads to notable compression [table 2] in manufacturing time frame[15]. Table 1: Manufacturing of rotor bracket Table 2: Rotor bracket model manufactured – model-Traditional approach New approach (RP-SLA) Time Time Activity Taken Activity Taken (days) (days) Casting of epoxy resin blanks 35 CAD data preparation, 08 translation and verification Tool development, process plan Pre-processing and 48 05 and Fixtures Stereolithography building Rough and finish machining 35 Post curing and finishing 05 Inspection and approval 7 Inspection and approval 07 Total time take = 125 Days Total time take = 25 Days 28
  9. 9. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEMEThe dimensional accuracy of the casting produced by the prototypes is measured by usingcoordinate measuring machine and the results are summarized in the table 3. The resultsreveled that the prototypes produced had close tolerance and accuracy and surface texture[16]. Table 3: Dimensional deviation of the spring (Rotor bracket model) Dimensional Sl. No. Drawing Dimensions Actual Dimension Deviation 1 Dia 256.25 / 256.000 Dia 256.24 0.19 Roundness 2 Dia 218.007 / 217.987 Dia 218.470 0.25 Roundness 3 Dia 208.35 / 208.00 Dia 208.37 0.21 Roundness 4 Dia 167.25 / 167.00 Dia 166.79 /166.70 0.17 Roundness 5 Dia 190.25 / 190.00 Dia 189.92 / 189.91 0.25 Roundness 6 Dia 6.6 / 6.4 (12 holes) Dia 6.20 / 6.4 - 7 5.1 / 5.0 5.19 / 5.08 - 8 13.5 /13.4 13.42 / 13.24 - 9 30 30 - 10 237.0 PCD 237.69 PCD 0.22 Roundness5. MANUFACTURING OF A GEAR BOX THOROUGH STEREOLITHOGRAPHY(CASE STUDY -II) The case study gives the analysis of the above influential factors in the field of rapidproduct development. The Gear Box casing is a component that was chosen for the purposeof the study which involves intricate shape and complexity as shown in the fig 8. Figure 8. CAD Model of Gear box The component was fabricated by the Stereolithography process to obtain a prototype.The time taken to built a prototype and also for the production of the actual part is as shownbelow [table 3]. 29
  10. 10. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME Table 3: Comparison of a fabrication of actual part and prototype of a Gear Box Prototype part Actual part CAD MODELLING TIME = 2 Months PART ENVELOPE = 430 mm X 330 mm X 190 mm Time taken to build actual metallic engine part = BUILD TIME ON SLA5000 SYSTEM = 12 months (Involves drawing, Designing of 2 Days per one part + 3 months for jigs and fixture, Process plan, fabrication & preparation moulds and castings Inspection). Thus from the above it can understood that the product development can be reduced by using the Rapid prototyping technology. RP MODEL ACTUAL METALLIC PART A PICTURE IS WORTH 1000 WORDS A PHYSICAL PART IS WORTH 1000 VIEWS ON A DRAWING5. CONCLUSION RP has the potential to optimize product development if it is embedded into theprocess chain., where the RP tool kit demonstrates the feasibility to achieve the continuousand unint6errupted support of design model preparation, process planning and prototypefabrication, which leads to a fast production of physical prototypes and thus to a shortening oftime required for product development in order to reduce the product time to market. Thusthe selected approach leads to a fast production of physical prototypes and parts by rapidtooling by shortening of the time required for product development where a remarkablereduction (in excess of 50%) in model preparation time is realized & reduction in the cost ofthe product as illustrated in the case study. These models exhibit necessary mechanical strength, dimensional accuracy andstress-strain linearity as demanded by photoelastic evaluation where the prototypes areproduced by epoxy resin which has brifreigent in nature. The presented study demonstrate thesuitability of rapid prototyping for the product development programme specifically in thedesign development phase where quick manufacturing solutions are paramount for timelycompletion of design iterative exercises. 30
  11. 11. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME6. REFERENCES 1. Prof.Kruth, J.P. (1991). Material incress manufacturing by rapid prototyping Techniques. CIRP ANNALS, Vol. 40, No 2, Page No: 603-614. 2. Krause, F.L.; Ciesla, M.; Stiel, CH.; Ulbrich, A. (2000). Enhanced RP for faster product development processes. Journal of Rapid prototyping, Vol 6, No2, Page No: 63-69. 3. Hon, K.K.B.; S.O.Onuh. S.O. (1998). Application of Taguchi method and new hatch style for quality improvement in Stereolithography. Proceedings of Institute of Mechanical Engineering, Part B, Vol 212, Page NO: 461- 472. 4. 3D Systems (1986) - User Manual, an Introduction to Stereolithography, USA 5. Paul F.Jacobs., (1992) Edition, Rapid prototyping and Manufacturing “Fundamentals of Stereolithography” .Mc Graw Hill.inc. (SME, Michigan) 6. Folkestad; James, E; Johnson, Russell.L. (2002).Integrated rapid prototyping and rapid tooling (IRPRT)”, Integrated Manufacturing Systems, Vol 13, N-2, Page No: 97-103. 7. Raju.B.S. (2004). M.Tech-Thesis., Studies on application of Rapid prototyping for the generation of photoelastic model, Div.Mechanical Engineering, Sir M.VIT, Bangalore. 8. Raju.B.S; Chandrashekar.U; Drakshayani.D.N; Chockalingam.K. (2010). Determining the influence of Layer thickness for rapid prototyping with Stereolithography process. International conference on Recent Advances in Mechanical Engineering (ICRAME 2010)., Collaboration with the University of Sheffield, UK. April 8 – 9th, PageNo: 593-597. 9. Pham.D.T.; S.S.Dimov.S.S. (2001), Rapid Manufacturing- Springer Publication. 10. Konig.W; Celiker.T; Song.Y.A. (1994). Rapid prototyping of metallic parts, Proc. Of the 3rd European conference. Rapid prototyping and Manufacturing, Nottingham, Page No: 245-256. 11. Krause.F.L; Ciesla.M; Luddemann, J; Stephan.M; Ulbrich.A. (1996). STEP basierte informations modeling for die product entwicklund, ZwF 91 (7/8): Page No: 316-322. 12. Krause.F.L; Ciesla.M. (1994). Technologische planung von Meβprozessen for koordinatenmeβmaschinen, ZwF 89 (3): Page No: 133-135. 13. Wisley.B.J ; Statistical analysis for engineering, P and A int., London. 14. Kruth.J.P; (1991) Material incress Manufacturing by rapid prototyping techniques, Annals of the CIRP, Vol. 40/2, Page No: 603 – 614. 15. Bjorke.O; (1991) How to make stereolithography into a practical tool for tool production, Annals of the CIRP, Vol.40/1, Page No: 175-178. 16. Childs.T.H.C and Juster N.P; (1994) Linear and geometric accuracies from Layer manufacturing, Annals of the CIRP, Vol.43/1, Page No: 163-166. 17. P.S.Senthil Kumar, Dr. S.Balasubramanian, Dr. R.K.Suresh and Dr. S.Arularasu, “Pairing of Intelligence Design Concept Method and Kano Model for Product Development”, International Journal of Design and Manufacturing Technology (IJDMT), Volume 1, Issue 1, 2010, pp. 1 - 13, Published by IAEME. 31

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