Rapid Prototyping RPT

Rapid Prototyping

IntroRapid prototyping is a techniques used to quickly fabricate a large scale model of a physical part or assembly into a small scale model using three-dimensional computer aided design (CAD) data. Construction of the part or assembly is usually done using 3D printing or "additive layer manufacturing" technology.(This process is called 3D printing).

HistoryThe roots of rapid prototyping technology can be traced to practices in,Topography (layered method for making a mold for raised relief paper topographical maps in 1892) and Photosculpture (photo-hardening photopolymer resin to form thin layers stacked to make a casting mold. It is the 19th century technique to create exact 3D model).The first methods for rapid came available in the late 1980.

3D PrintingIt is an additive manufacturing technology and involves the use of various materials. In this technology successive layers of material create a 3D object. 3D printing technology actually is said to be more affordable, easy to use and speedy than the additive manufacturing technologies. Though production applications are actually dominated by the additive manufacturing technologies, 3D has a great potential to prove useful in the production applications.

Materials Used Plastics,Ceramics,Wax,Wood,Metals(Stainless steel to Titanium).

Basic StepsCreate a CAD model of the design

Convert the CAD model to STL format (stereolithography)

Slice the STL file into thin cross-sectional layers

Construct the model one layer atop another

Clean and finish the model Process Stereolithography (SLA for stereolithography apparatus), Selective laser sintering (SLS), Fused deposition modeling (FDM), Laminated object manufacturing (LOM), Inkjet systems three dimensional printing (3DP).StereolithographyStereolithography, also known as 3-D layering or 3-D printing, allows you to create solid, plastic, three-dimensional (3-D) objects from CAD drawings in a matter of hours. Whether you are a mechanical engineer wanting to verify the fit of a part or an inventor looking to create a plastic prototype of an invention, stereolithography gives you a fast, easy way to turn CAD drawings into real objects.

FDM(FDM) is a solid-based rapid prototyping method that extrudes material, layer-by-layer, to build a model. A thread of plastic is fed into an extrusion head, where it is heated into a semi-liquid state and extruded through a very small hole onto the previous layer of material. Support material is also laid down in a similar manner.

Laminated object manufacturing (LOM)As the name implies the process laminates thin sheets of film (paper or plastic). The laser has only to cut/scan the periphery of each layer.

Process.,The build material (paper with a thermo-setting resin glue on its under side) is stretched from a supply roller across an anvil or platform to a take- up roller on the other side. A heated roller passes over the paper bonding it to the platform or previous layer.

A laser, focused to penetrate through one thickness of paper cuts the profile of that layer. The excess paper around and inside the model is etched into small squares to facilitate its removal.The process of gluing and cutting continuous layer by layer until the model is complete.

To reduce the build time, double or even triple layers are cut at one time which increases the size of the steps on curved surfaces and the post processing necessary to smooth those surfaces.

Selective laser sinteringSelective Laser Sintering (SLS) is an additive manufacturing technique that uses a laser as the power source to sinter powdered material (typically metal), aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure

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