A review: Implementation of Computer-Aided Design for Rapid Manufacturing and Layer Manufacturing Technologies

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1 A review: Implementation of Computer-Aided Design for Rapid Manufacturing and Layer Manufacturing Technologies Atul Kumar Department of Mechanical Engineering SRM University NCR Campus, Delhi Meerut Road, Ghaziabad Pin code , (U. P.), India Atishey Mittal Department of Mechanical Engineering SRM University NCR Campus, Delhi Meerut Road, Ghaziabad Pin code , (U. P.), India Abstract In Hodiernal industry, a great effort has been made in order to customize products and give them optimum value by adopting the CAD/CAM/CAE/RP advance system. Interest in multifunctional structures made automatically from interdiscipline poses is challenge for today s additive manufacturing (AM) technologies. However the ability to process the CAD tools is a fundamental advantage for adaptive manufacturing technology. Additive Manufacturing (AM) technologies, informally called rapid prototyping, enable the fabrication of the object directly from the CAD geometric information. The CAD model can be generated from many sources, including CAD designs and conversion data from the reverse engineering. The application of 3D printing technologies, however, promises to merge rapid prototyping capabilities with the high-volume over the conventional manufacturing process. The authors present their experience in industrial application of additive fabrication through various prospective of CAD elements. The paper attempts to understand the state of the art and the CAD potential to implementation in RP technologies and also understand the limits and opportunities of an integrated approach. (Abstract) quality, product design, and innovation and delivery services are the primary steps to make the product successes [1]. The terms of concurrent engineering (CE) has been around the manufacturing circles from early 1960s in various forms requesting the use of multidisciplinary teams to accelerate product introduction. However, in 1987, the concept was given the name concurrent engineering with an appropriate definition by the United States Defense Advanced Research Projects Agency. CE involves, a systematic and simultaneous approach to the integrated design of products and their related processes including marketing, manufacturing, sales, and purchasing. Further, it involves formation of multidisciplinary teams for the rapid product development and introduction of the product into the market. CE could be considered as a management strategy rather than the manufacturing strategy [2]. Keywords Additive Manufacturing, Rapid Prototyping, CAD/CAM/CAE, Reverse Engineering I. INTRODUCTION Due to the daily increase in complexity of industrial manufacturing, international competition and market globalization, there is demand for higher flexibility and greater efficiency and traditional manufacturing processes may not be able to meet all the requirement of today s products. Manufacturing industries have evolved tremendously from cottage industries in the early 16th century to the global force as it stands today. The present world market has some challenges include higher competition, shorter product life cycles, greater product diversity, fragmented markets, variety and complexity, and smaller batch sizes to satisfy a variety of customer profiles Furthermore, non-price factors, such as Fig. 1. The RP wheel depicting the major characteristics of RP [1]

2 Today, many manufacturing industries are under pressure to achieve the goal of the objectives within limited capital available for new investments. However, traditional manufacturing processes might not meet all requirements and are not economical enough in most cases because of the intricate shapes and internal configurations needed of models with their delicate material variations. In recent years, manufacturing industry has been facing the challenge of losing competitiveness in mass production. Due to important factors such as lower labour costs, lower taxes or on-site access to raw materials, and mass production has migrated to make the highly productive countries. However, worldwide industry is more advanced in technological aspects and is in need of a qualitative advantage in the development of new technologies. A great effort has been made in order to customise products and give them an added value by developing new fabrication technologies. Additive fabrication is a powerful tool that offers the necessary competitiveness to manufacturing companies. Additive Manufacturing (AM) processes that are based on layer-by-layer manufacturing are identified as an effective approach to overcome these challenges. The Additive Manufacturing is also known as free-form fabrication or desktop manufacturing or layer manufacturing technology. However, few important RP processes names Stereo lithography (SL), Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM) and Laminated Object Manufacturing (LOM) [3]. For adaptive fabrication the electronic information required to describe the physical object with 3D data. There are two possible starting points: a computer model or a physical model. The computer model created by a CAD system can be either a surface model or a solid model. On the other hand, 3D data from the physical model is not at all straightforward. It requires data acquisition through a method known as reverse engineering. In reverse engineering, a wide range of equipment can be used, such as coordinate measuring machine (CMM) or a laser digitizer, to capture data points of the physical model and reconstruct it in a CAD system. The 3D-digitising and reconstruction of 3D-shapes by reverse engineering has numerous applications so that, this is an interesting research and development field that related the reverse engineering to rapid prototyping shown in Figure 2 [4]. Fig. 2. Relationship between rapid prototyping, reverse engineering and CAD Today we are witnessing a steady rise in the number of virtual enterprises in many facets of industry. This paper reviews the developments in adaptive manufacturing with CAD system. It also illustrates a new RP wheel developed to satisfy the emerging technological application of virtual enterprises in the information era and provides suggestions for the future research trends in layer by layer manufacturing. II. INTEGRATION OF COMPUTER-AIDED DESIGN AND RAPID MANUFACTURING CAD system is available for assisting in the design of large buildings and CAD technology holds within it the knowledge associated with a particular type of product, including geometric, electrical, thermal, dynamic, and static behavior. CAD also allows the user to focus on small features of a large product, maintaining data integrity and ordering it to understand how subsystems integrate with the remainder. Additive Manufacturing technology primarily makes use of the output from mechanical engineering, 3D Solid Modeling CAD software. A model or component is modeled on a Computer-Aided Design (CAD) system [1]. A CAD model, usually a solid model, is created in a commercial CAD system, like CATIA or Pro/Engineer. CAD model in the form of STL data and slice data has been shown in Fig.3. 3-D Solid Model 3-D Model in STL form Slice data Model Fig. 3. CAD model in the form of STL data and slice data [1] The prototypes created with RP technologies will serve most if not all of these roles. Parallel phases between the computer modeling process and prototyping process can be drawn as seen in Table 1. The three phases are described as follows:

3 Table 1. Parallel phases between the computer modeling and prototyping process [1] Phase Geometric modeling Prototyping First 2D wireframe Started in mid-1960s Few straight lines on display may be circuit path on a PCB plan view of a mechanical component Natural drafting technique Manual prototyping Traditional practice for many centuries Prototyping as a skilled crafts is traditional and manual based on material of prototype Natural prototyping technique the model. Prototype is then tested or verified and suggested engineering changes are once again incorporated during the solid modeling stage. Thus the steps involved in the process can be summed up as: Step-1: Geometric data CAD packages Digitize scanners, MR Step-2: Data conversion Convert the all data into.stl) format Second 3D curve and surface modeling Mid-1970s Increasing complexity Representing more information about, precise shape, size and surface contour of parts Soft or virtual prototyping Mid-1970s Increasing complexity Virtual prototype can be stressed simulated and tested, with exact mechanical and other properties. Step-3: - layer thickness determines Accuracy Build time Quality of surface Step-4: - Building of parts Third Solid modeling Early 1980s Edges, surfaces and holes are knitted together to form a cohesive whole Computer can determine the inside of an object from the outside. Perhaps, more importantly, it can trace across the object and readily find all intersecting surfaces and edges No longer ambiguous but exact Rapid prototyping Mid-1980s Benefit of a hard prototype made in a very short turnaround time is its main strong point (relies on CAD modeling) Hard prototype can also be used for limited testing Prototype can also assist in the manufacturing of the products Three-dimensional CAD data of the part from the CAD system are converted to the sliced cross-sectional data. This requirement ensures that all horizontal cross-sections that are essential to RP are closed curves to create the solid object. The solid or surface model to be built is next converted into a format dubbed the STL (Stereo Lithography) file format which originates from 3D Systems. The STL file format approximates the surfaces of the model by polygons. Highly curved surfaces must employ many polygons, which mean that STL files for curved parts can be very large. A computer program analyzes a.stl file that defines the model to be fabricated and slices the model into cross-sections. The cross-sections are systematically recreated through the solidification of either liquids or powders and then combined to form a 3D model [5]. Another possibility is that the crosssections are already thin, solid laminations and these thin laminations are glued together with adhesives to form a 3D model. Other similar methods may also be employed to build Step-5: - Post processing Remove post support and polish the model for display functional requirement. III. MATERIALS FOR RAPOID MANIFACTURING A day, when fully developed process will be capable to directly generating parts from computerized data or directly from CAD model, is the ultimate dream of manufacturing engineers. All manufacturing process can be divided in four groups namely: Forming process, removal process joining process and adaptive process. For joining and removal process the work material is essentially in solid state. In forming process the original state of work material can be either liquid, solid or powder but in case of adaptive manufacturing process the original state of work material can also be liquid, solid (in the form of a foil or wire) or powder. Table 2 Earlier AM technologies were built around materials that were already available and that had been developed to suit other processes. However, the AM processes are Jetting Head Fullcure M (Model Material) and Fullcure S (Support Material) used on an AM machines. As we came to understand the technology better, materials were developed specifically to suit AM processes. Materials have been tuned to suit more closely the operating parameters of the different processes and to provide better output parts [6]. As a result, parts are now much more accurate, stronger, and longer lasting and it is even possible to process metals with some AM technologies. In turn, these new materials have resulted in the processes being tuned to produce higher temperature materials, smaller feature sizes, and faster throughput.

4 Table 2. Classification of the AM process based on raw material state [6] So No. State of Materials 1 Liquid Liquid photo, Liquid thermal, and Melting and solidification 2 Solid Selective gluing and cutting and Foil 3 Powder Selective sintering Selective powder binding IV. Mechanism Type of Energy Suitable name of the Process and Monochromatic Light and Heat Adhesive bonding cutting, light and and Heat and chemical bond Stereolithography (SL), Solid ground curing (SGC) Thermal Stereolithography Fused Deposition Modeling (FDM) Laminated Object Manufacturing (LOM) and solid foil Selective Laser Sintering (SLS), 3-D printing and Selective powder binding HISTORICAL DEVELOPMENTS IN ADVANCED MANUFACTURING TECHNOLOGIES The development of RP is closely tied in with the development of applications of computers in the industry. The declining cost of computers, especially of personal computers, has altered the way a factory works. The increase in the use of computers has spurred the advancement in many computerrelated areas including computer-aided design (CAD), computer- aided manufacturing (CAM) and computer numerical control (CNC) machine tools. In particular, the emergence of RP systems could not have been possible without the existence of CAD. However, through careful examinations of the numerous RP systems in existence today, it can be easily deduced that other than CAD, many other technologies and advancements in other fields such as manufacturing systems and materials have also been crucial in the development of RP systems. Table 3 traces the historical development of relevant technologies related to RP from the estimated date of inception [2]. In sixteen s, the first rapid prototyping technique became accessible in the later eighties and used for production of prototype and model parts. In seventies, Herbert Voelcker, engineering professor developed the basic tools of mathematics that clearly describe the three dimensional aspects and resulted in the earliest theories of algorithmic and mathematical theories for solid modeling. In eighties, Carl Deckard, pioneered the layer based manufacturing, he thought of building up the model layer by layer and printed 3D models by utilizing laser light for fusing metal powder in solid prototypes, single layer at a time [1]. Technique called Selective Laser Sintering. Table 3. Historical development of Rapid Prototype [1,2] Year of Commencement Improvement in Technology 1600 Manual and animal Labour 1750 Craftsman ship 1770 Mechanization 1946 First computer 1952 Beginning of CAD and First numerical control (NC) machine tool 1960 First commercial Laser 1961 First commercial Robot 1963 First interactive graphics system (early version of computer-aided design) 1970 Development in CAD, CAPP, AM, and CIM 1988 First commercial rapid prototyping system 1990 Concept of Virtual product Nowadays, the computer engineer has to simply sketch the ideas on the computer screen with the help of a design program that is computer aided. Computer aided designing allows to make modification as required and can create a physical prototype that is a precise and proper 3D object. Today the computer engineer has to simply sketch the ideas on the computer screen with the help of a design program that is computer aided. Computer aided designing allows to make modification as required and you can create a physical prototype that is a precise and proper 3D object. V. RESEARCH TRENDS AND DEVELOPMENTS IN AM More generally, the unique capabilities of AM technologies enable new opportunities for customization, very significant improvements in product performance, multifunctionality, and lower overall manufacturing costs. These unique capabilities include: Shape complexity: it is possible to build virtually any shape, lot sizes of one are practical, customized geometries are achieved readily, and shape optimization is enabled. Material complexity: material can be processed one point, or one layer, at a time, enabling the manufacture of parts with complex material compositions and designed property gradients. Hierarchical complexity: hierarchical multi-scale structures can be designed and fabricated from the microstructure through geometric macrostructure

5 New CAD and Design for Manufacturing (DFM) approaches are needed in order to take advantage of these capabilities. New CAD systems had to be developed to enable efficient shape, and size modeling and part design. However, if suitable CAD and DFM methods and tools can be developed, designers can design devices with significantly improved performance that fully utilize the material and manufacturing processes. The definition of DFM can be proposed as DFM for Additive Manufacturing (DFAM). DFAM is a synthesis of shapes, sizes, geometric macrostructures, and material compositions and microstructures to best utilize manufacturing process capabilities to achieve desired performance and other lifecycle objectives [7]. The emerging Multiple Material Additive Manufacturing (MMAM) technology can enhance the performance of AM parts by adding more complexity and functionality. Using MMAM technologies it is possible to improve part performance by varying material compositions or type within the layers; this is not achievable by conventional manufacturing processes. In fact, MMAM represents a whole new paradigm and range of opportunities for design, functionality, and cost effective high value products. There are many applications that can potentially benefit from the development of MMAM technologies [8]. Some researchers are focus on cellular materials and structures, which can lead to designs that are very geometrically complex. In order to take advantage of AM capabilities, new design and CAD methods must be developed. The Manufacturable Elements (MELs) are proposed as an intermediate representation for supporting the manufacturing related aspects of the method. These MELs represent process planning information for discrete geometric regions of a part and also enable process simulation. The development of AM technology is the expiration of many of the foundational patents for key AM processes. Already, we are seeing an explosion of material extrusion vendors and systems since the first FDM patents expired in the early 2010s. Patents in the stereolithography, laser sintering, and LOM areas are expiring (or have already expired) and may lead to a proliferation of technologies, processes, machines, and companies. VI. FUTURE DIRECTION OF RAPID MANUFACTURING The ability to grow parts may form the core to the answer to that question. The true benefit behind AM is the fact that we do not really need to design the part according to how it is to be manufactured. Avoiding the need to consider how the part can be manufactured certainly simplifies the process of design and allows the designer to focus more on the intended application. With improvements in AM technology the speed, quality, accuracy, and material properties have all developed to the extent that parts can be made for final use and not just for prototyping. Certainly we will continue to use this technology for prototyping for years to come, but we are already entering a time when it is commonplace to manufacture products in low volumes or unique products using AM. Eventually we may see these machines being used as home fabrication devices [9]. VII. APPLICATIONS OF A INTEGRATED APPROACH Adaptive manufacturing has possibility to reduce the product design and development cycle time from conception to market up to percent. While at the same it has capability to cut the costs due to major innovation by integrate the CAD and AM system in manufacturing. Therefore, RP technologies are successfully used by various industries like aerospace, automobile, jewelry, coin making, saddletrees etc. Its various applications are listed below- In medical field: Rapid prototyping is used for diagnosis, surgery planning, training, and for design and manufacture of the custom implants and also the model of skull. The conversion of CT scan or MRI results which are taken as input and then converted in to CAD file then analyze those files with the help of CAM software then production that product with rapid prototyping [10]. In Mechanical Engineering- Rapid Prototyping is often used as a proof of concept and visualizing the object. Rapid Prototyping has wide applications in the Automobile and Aerospace Industry. In Electrical appliances: The house holding electrical appliances are widely manufactured by RP techniques. These techniques are very useful for manufacturing the special contours in an electrical item. In textile: The complicated contour profile dresses are designing in the 3D model with aid of computer and directly inter connected with manufacturing machine. In Furniture Designing: This model has low weight and no temporary and permanent joints. It is made up of a single piece without any joints with different profiles. In Foot-Ware Designing: The foot-ware for a human comfort is manufacturing in RP technique. This type of foot-ware should have light weight and stronger than the conventional model. And also the complicated design of foot-ware is developed in the RP technique models without any fastener. The reliability is very high compared with conventional model. Architectural Interior design An RP technique plays an important role in architectural interior design like stature, wall mountings and toys. The RP model of

6 interior decoration has good surface finishing and aesthetics. It is also used in crafts, arts and Reverse Engineering applications, Short Production Runs and Rapid Tooling. VIII. CONCLUSION [8] S.H. Choi*, H.H. Cheun, A multi-material virtual prototyping system, Computer-Aided Design 37 (2005) [9] Gibson, I., Rosen, D.W., and Stucker, B Additive manufacturing technologies. New York, NY, USA: Springer [10] Barron, J.A., et al., Biological laser printing: a novel technique for creating heterogeneous 3-dimensional cell patterns. Biomedical Microdevices, 6, , Additive layered manufacturing is a set of emerging technologies that are becoming a serious competitor to machining and forming technologies. Due to their obvious advantages in product customization, maximum material savings, and gradual and controlled porous structures, additive technologies are becoming more interesting to many industrial sectors such as biomedical, aerospace, automotive and tooling. With the introduction of new materials and active principles, the ALM technologies that originally were only used for prototypes and models have now been converted into technologies that can fabricate fully-dense functional parts with high added value, RP typically falls within the range of physical prototypes, which are usually fairly accurate and can be implemented on a component level or at a system level. The versatility and range of different prototypes, from complete systems to individual components, that can be produced by RP at varying degrees of approximation makes it an important tool for prototyping in the product development process. Adding the major advantage of fast delivery, it has become an important component in the prototyping arsenal that cannot be ignored. References [1] Chee Kai Chua, Kah Fai Leong, Chu Sing Lim Chapter 1, Liquid-Based Rapid Prototyping Systems (Rapid Prototyping - Principles and Applications - Third Edition World Scientific Publishing Co. Pte. Ltd. pp1-27, 2015 [2] Sev V. Nagalingam and Grier C.I. Lin, Latest developments in CIM, Robotics and Computer Integrated Manufacturing 15,pp , [3] Chua, C.K. and Leong, K.F. (2000) in: Rapid Prototyping: Principles and Applications in Manufacturing, Pub: World Scientific, Volume 1. [4] A. Kumar, P. K. Jain and P. M. Pathak, Industrial Application of Point Cloud / Stl Data for Reverse Engineering, Scientific Book, Chapter 38 in DAAAM International Scientific Book 2012, pp , B. Katalinic (Ed.), Published by DAAAM International, ISBN , ISSN , Vienna, Austria [5] Gibson, I. Advanced manufacturing technology for medical applications: Reverse engineering, software conversion and rapid prototyping. West Sussex, England: Wiley [6] Ghosh Amitabha, Rapid Prototyping- A Brief Introduction, Affiliated East-West Press Pvt Ltd, New Delhi, India, 1997 [7] David W. Rosen, Computer-Aided Design for Additive Manufacturing of Cellular Structures, Computer-Aided Design & Applications, Vol. 4, No. 5, pp , 2007.