Introduction to rp


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Introduction to rp

  1. 1. RAPID PROTOTYPING: Rapid Prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design (CAD) data. Construction of the part or assembly is usually done using 3D printing technology. The first techniques for rapid prototyping became available in the late 1980s and were used to produce models and prototype parts. History: One such report was the 1997 Rapid Prototyping in Europe and Japan Panel Report [2] in which Joseph J. Beaman [5] founder of DTM Corporation [DTM RapidTool pictured] provides a historical perspective : The roots of rapid prototyping technology can be traced to practices in topography and photosculpture. Within TOPOGRAPHY Blanther (1892) suggested a layered method for making a mold for raised relief paper topographical maps .The process involved cutting the contour lines on a series of plates which were then stacked. Matsubara (1974) of Mitsubishi proposed a topographical process with a photo-hardening photopolymer resin to form thin layers stacked to make a casting mold. PHOTOSCULPTURE was a 19th-century technique to create exact three-dimensional replicas of objects. Most famously Francois Willeme (1860) placed 24 cameras in a circular array and simultaneously photographed an object.The silhouette of each photograph was then used to carve a replica. Morioka (1935, 1944) developed a hybrid photosculpture and topographic process using structured light to photographically create contour lines of an object.The lines could then be developed into sheets and cut and stacked, or projected onto stock material for carving. The Munz(1956) Process reproduced a three-dimensional image of an object by selectively exposing, layer by layer, a photo emulsion on a lowering piston. After fixing, a solid transparent cylinder contains an image of the object. The technologies referred to as Solid Freeform Fabrication are what we recognize today as Rapid Prototyping, 3D Printing or Additive Manufacturing : Swainson (1977), Schwerzel (1984) Worked on polymerization of a photosensitive polymer at the intersection of two computer controlled laser beams. Ciraud (1972)Considered magnetostatic or electrostatic deposition with electron beam, laser or plasma for sintered surface cladding. These were all proposed but it is unknown if working machines were built. Hideo Kodama of Nagoya Municipal Industrial Research Institute was the first to publish an account of a solid model fabricated using a photopolymer rapid prototyping system (1981). [2] Even at that early date the technology was seen as having a place in manufacturing practice. A low resolution, low strength output had value in design verification, mould making, production jigs and other areas. Applications:
  2. 2. Advantages: The Prototype gives the user a fair idea about the final look of the product. Rapid prototyping can enhance the early visibility. It is easier to find the design flaws in the early developmental stages. Active participation among the users and producer is encouraged by rapid prototyping. As the development costs are reduced, Rapid prototyping proves to be cost effective. The user can get a higher output. The deficiencies in the earlier prototypes can be detected and rectified in time. The speed of system development is increased. It is possible to get immediate feedback from the user. There is better communication between the user and designer as the requirements and expectations are expressed in the beginning itself. High quality product is easily delivered by way of Rapid prototyping. Rapid prototyping enables development time and costs. There are many innovative ways in which Rapid prototyping can be used. DISADVANTAGES: Some people are of the opinion that rapid prototyping is not effective because, in actual, it fails in replication of the real product or system. It could so happen that some important developmental steps could be omitted to get a quick and cheap working model. This can be one of the greatest disadvantages of rapid prototyping. Another disadvantage of rapid prototyping is one in which many problems are overlooked resulting in endless rectifications and revisions. One more disadvantage of rapid prototyping is that it may not be suitable for large sized applications. Reverse and Re-Engineering Reverse Engineering: A method of recreating software system components for which the source code is missing, out of date, or is otherwise not in agreement with existing components. Disassembles and decompilers are examples of Reverse engineering tools. The process of analyzing an existing system to identify its components and their inter relations interrelationships, and to create representations of the system in another form or at a higher level of abstraction .
  3. 3. Advantages: * High degree of Precision for wide range of surfaces as compared to manual measurements * Quicker turnaround time as compared to conventional methods * Reproduce existing machine part or object efficiently & cost- effectively * Faster time-to-market for your products Re-Engineering: Reanalysis and radical redesign that is not bound by previous obsolete solutions. (Contrast TQM - incremental improvement) Coined by management guru Michael Hammer, it's a quality improvement tool: start from scratch, question assumptions, and radically redesign what people do and how they work. Reengineering Benefits Lower costs. Evidence from a number of US projects suggests that reengineering an existing system costs significantly less than new system development. Ulrich, for example reports on a reengineering project that cost $12 million, compared to estimated redevelopment costs of $50 million. Lower risks. Reengineering is based on incremental improvement of systems, rather than radical system replacement. The risk of losing critical business knowledge, which may be embedded in a legacy system, or of producing a system that does not meet its users’ real needs, is drastically reduced. Better use of existing staff. Existing staff expertise can be maintained, and extended accommodate new skills during reengineering. The incremental nature of reengineering means that existing staff skills can evolve as the system evolves. The approach carries less risk and expense which is associated with hiring new staff. Revelation of business rules. As a system is reengineered, business rules that are embedded in the system are rediscovered. This is particularly true where the rules govern exceptional situations. Incremental development. Reengineering can be carried out in stages, as budget and resources are available. The operational organisation always has a working system, and end users are able to gradually adapt to the reengineered as it is delivered in increments.
  4. 4. Concurrent engineering Concurrent engineering is a work methodology based on the parallelization of tasks (i.e. performing tasks concurrently). It refers to an approach used in product development in which functions of design engineering, manufacturing engineering and other functions are integrated to reduce the elapsed time required to bring a new product to the market. Concurrent Engineering (CE) is a systematic approach to integrated product development that emphasizes the response to customer expectations. It embodies team values of co-operation, trust and sharing in such a manner that decision making is by consensus, involving all perspectives in parallel, from the beginning of the product life cycle Advantages: Manufacturing Personnel are able to identify production capabilities and capacities .They have thus the opportunity to inform the design group about the suitability of certain materials on the flipsides the designer would know the suitability of certain designs in aiding in cost reduction and quality improvement in production/assembly process. Early opportunities for design or procurement of critical tooling, some of which might have long lead times. early consideration of the Technical Feasibility of a particular design or a portion of a design. Again this can avoid serious problems during production. Disadvantages of concurrent design[edit] Concurrent design creates its own issues, such as the implementation of early design reviews, the dependency on efficient communication between engineers and teams, software compatibility, and opening up the design process.[9] A concurrent design process usually requires that computer models (computer aided design, finite element analysis) are exchanged efficiently, something that can be difficult in practice. If such issues are not addressed properly, concurrent design may not work effectively.