Rapid Prototyping

Rapid prototyping is the automatic construction of physical objects using additive manufacturing technology. used to produce models and prototype parts. modelsprototype

Development Manual Prototyping by craftsman 1970 prototyping in CAD, virtual environment 1980, Rapid Prototyping (RP) by layer-by-layer material deposition. CAD/CAM

The standard data interface between CAD software and the machines is the STL file format.interfaceSTL file format An STL file approximates the shape of a part or assembly using triangular facets. Smaller facets produce a higher quality surface. SLC: Slice format, CLI: Common Layer Interface

Some solid freeform fabrication techniques use two materials in the course of constructing parts.solid freeform fabrication The first material is the part material and the second is the support material (to support overhanging features during construction). The support material is later removed by heat or dissolved away with a solvent or water.

Advantages during development... No tooling costs Short production times Comparatively low unit prices Constructional simplification: e.g. instead of housing, lid and screws, 1 complete sintered unit can be made Test- and functional products can be produced in small batches Formal- and functional variants possible

... production... No tooling costs for small- and medium-sized batches Low tooling costs for larger batches Product customization possible without additional costs... and the production of spare parts. No tooling management necessary Spare parts need no longer be kept but produced as required Unlimited subsequent delivery

Prototyping technologiesBase materials Selective laser sinteringSelective laser sintering (SLS)ThermoplasticsThermoplastics, metals powdersmetals Fused deposition modelingFused deposition modeling (FDM) ThermoplasticsThermoplastics, eutectic metals.eutectic StereolithographyStereolithography (SLA)photopolymer Laminated object manufacturingLaminated object manufacturing (LOM) Paper Electron beam meltingElectron beam melting (EBM)Titanium alloys 3D printing3D printing (3DP)Various materials

Stereolithography (SL) is an additive manufacturing technology for producing models, prototypes, patterns, and in some cases, production parts. UV laser and liquid photo curable resin Laser cures resin

can be used as master patterns for injection molding, thermoforming, blow molding, and also in various metal casting processes Costly

To create an SLA rapid prototype, first a three- dimensional CAD part is "sliced" horizontally into cross-sections between 0.002" and 0.006" thick. The slices are fed to 3D Systems' Stereolithography Apparatus. Inside the stereolithography chamber of the apparatus, an ultraviolet laser traces the first layer of the part on a metal platen, submerged just below the surface of a vat of photo-sensitive polymer.photo-sensitive polymer

Wherever the laser touches the liquid, it solidifies. Once the layer is traced, the platen sinks the thickness of a layer below the level of the liquid. A sweeper bar moves across the surface of the last layer, making sure there is the exact amount of resin on top. The next layer is then built upon the previous layer. In this manner the entire part is built from the bottom up, with the completed sections of the part remaining submerged.

In the Selective Laser Sintering (SLS) process, three-dimensional parts are created by fusing (or sintering) powdered thermoplastic materials with the heat from an infrared laser beam. The object’s creation is accomplished by repeatedly fusing thin powder layers using a laser beam. This additive manufacturing sequence produces parts that gradually increase in size until they reach the prescribed dimensions. These prototypes are created directly from 3D CAD models.

Selective laser sintering is an additive manufacturing technique that uses a high power laser (for example, a carbon dioxide laser) to fuse small particles of plastic, metal (Direct Metal Laser Sintering), ceramic, or glass powders into a mass representing a desired 3-dimensional objectlasercarbon dioxide laserplasticmetalDirect Metal Laser Sinteringceramicglass

powder polymers (nylon, also glass-filled or with other fillers, and polystyrene), metals (steel, titanium, alloy mixtures, and composites) and green sand.polymersnylonpolystyrenesteeltitaniumgreen sand

A plastic filament or metal wire is unwound from a coil and supplies material to an extrusion nozzle which can turn on and off the flow.extrusion The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism,

The model or part is produced by extruding small beads of thermoplastic material to form layers as the material hardens immediately after extrusion from the nozzle. acrylonitrile butadiene styrene (ABS) polymer, the FDM technology can also be used withpolycarbonates, polycaprolactone, polyph enylsulfones and waxes.acrylonitrile butadiene styrenepolycarbonatespolycaprolactonepolyph enylsulfones

In it, layers of adhesive-coated paper, plastic, or metal laminates are successively glued together and cut to shape with a knife or laser cutter.paperplasticmetallaser cutter

The process is performed as follows: 1.Sheet is adhered to a substrate with a heated roller. 2.Laser traces desired dimensions of prototype. 3.Laser cross hatches non-part area to facilitate waste removal. 4.Platform with completed layer moves down out of the way. 5.Fresh sheet of material is rolled into position. 6.Platform moves up into position to receive next layer. 7.The process is repeated.

Features Low cost due to readily available raw material Dimensional accuracy is slightly less than that of Stereolithography and Selective laser sintering but no milling step is necessary.StereolithographySelective laser sintering Relatively large parts may be made, because no chemical reaction is necessary