RAPID PROTOTYPING

RAPID PROTOTYPING

Abstract:

The Design of real life objectives even conventionally represented in the form of 2D sketches and view due to the dimensional limitations in the medium. There are also efforts reported where the objects are depicted as 3 D images using holographic techniques. Systems are available where in the medium continues to be 2D but the viewer gets the 3d image (stereovision) using two slightly offset views. In all the above cases, the object is not physical so that one can fill it, assemble or even subject it to strength analysis using photoelastisity. Therefore, physical models call prototype are invariably prepared and subjected to various taste as part of the design evaluation process This prototype may be scaled version made up of alternate material or may be full scale product made up of the actual material.

Prototype manufacturing is very time consuming process involving all stages of manufacturer such as process planning, machining, assembly etc. in addition to the function of PPC. The long cycle time and the high cost of this process limit the no. of designs alternatives that could be evaluated. Therefore, people thought of developing processes that would directly give the physical prototype from the cad model without going through various manufacturing steps. In other words, what they wanted was a system where in required object is printed in 3D just like a laser printer prints on 2D sheet. This led to development of the class of a process that are today known as rapid prototyping which refers to any process in which physical object is obtained directly from its cad model without explicitly going through various steps of manufacturing a part.

Today, RP has established itself as a very effective tool for design visualization. In addition to visualization, it can be used in testing the assemblies for their intended function and interference with other elements. RP parts are used as prototype in photo elastic testing since the materials used in most of the RP processes are polymer ideally suited for such tests. Since it is possible to produce a transparent part by appropriate choice of materials RP parts have been used to analyze fluid flow problems. A certain automobile engine designer has fixed a leak in the engine manifold by using RP part in the place of actual one during testing. RP have also help a physician to visualize and repair the damage by producing the hipbone of patient as an RP part from the scanned image of the damage part.

RP is not only for design visualization and evaluation. They also help in producing the parts in short time. After the design evaluation the RP part can be used as a pattern for making mould. Investment casting wax can be used as a RP material and hence it can be directly used in the investment casting process. The RP part also can be used as template for copy milling. Although presently only proprietary plastic materials can be used in RP, some processes such as selective laser sintering (SLS), 3D printing and ballistic particle manufacture (BPM) show promise of producing RP parts out of any materials and hence directly the moulding dies can be manufactured using this process .The effectiveness of RP has been realized by Indian designer in various industries and they are keep to use RP part for their design verification due to the drastic reduction in time and cost of product development the limitations of RP parts such as in adequate surface finish and dimensional accuracy and less material options are slowly getting overcome .

There are seven RP processors today, viz. stereo lithography (SLS), solid ground curing (SGC), laminated object manufacture (LOM) fused deposition modeling (FDM) selective laser sintering (SLS) 3D printing and ballistic particle manufacturing (BPM).

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