3D printing is considered distinct from traditional machining techniques, which mostly rely on the removal of material by methods such as cutting or drilling (subtractive processes) Then limited to industrial use only but recently It can be used for personal purpose Charles Hull inventor of 3d printer
An STL file approximates the shape of a part or assembly using triangular facets. Smaller facets produce a higher quality surface. PLY is a scanner generated input file format, and VRML (or WRL) files are often used as input for 3D printing technologies that are able to print in full color.
Typical layer thickness is around 100 micrometres (0.1 mm) The particles (3D dots) are around 50 to 100 micrometres (0.05–0.1 mm) in diameter depending on the method used and the size and complexity of the model.
3Introduction● Additive manufacturing or 3D printing is aprocess of making a three-dimensional solidobject of virtually any shape from a digitalmodel● 3D printing is achieved using an additiveprocess, where successive layers of material arelaid down in different shapes● Printed solid model was made in 1981
4Principles : Modeling● Takes virtual blueprints from computer aideddesign (CAD)● “Slices” them into digital cross-sections● It is a WYSIWYG process where the virtualmodel● A standard data interface between CADsoftware and the machines is the STL fileformat.
5Principles : Printing● Reads the design from an .stl file and lays downsuccessive layers of liquid or materials● Ability to create almost any shape or geometricfeature● Printer resolution describes layer thickness● Can take anywhere from several hours toseveral days● Injection molding and Additive manufacturing
6Manufacturing : Extrusion deposition● uses a plastic filament or metal wire that is wound on acoil and unreeled to supply material to an extrusionnozzle● The nozzle heats to melt the material and can be movedin both horizontal and vertical directions by anumerically controlled mechanism that is directlycontrolled by a computer-aided manufacturing (CAM)software package.● The model or part is produced by extruding small beadsof thermoplastic material to form layers as the materialhardens immediately after extrusion from the nozzle.Stepper motors or servo motors are typically employedto move the extrusion head.
7Extrusion Deposition : Materials● Various polymers are used, including acrylonitrilebutadiene styrene (ABS), polycarbonate (PC),polylactic acid (PLA), high density polyethylene(HDPE), PC/ABS, and polyphenylsulfone (PPSU).● In general the polymer is in the form of a filament,which can be fabricated from virgin resins or frompost-consumer waste by recyclebots.● FDM usually cannot produce stalactite-like structures(Shape Restriction)
9Theories● Stereolithographyposition a perforated platform just below the surface of avat of liquid photopolymer. A UV laser beam then tracesthe first slice of an object on the surface of this liquid,causing a very thin layer of photopolymer to harden. Theperforated platform is then lowered very slightly andanother slice is traced out and hardened by the laser.Another slice is then created, and then another, until acomplete object has been printed and can be removed fromthe vat of photopolymer, drained of excess liquid, andcured. Stereolithographic printers remain one of the mostaccurate types of hardware for fabricating 3D output
10Theory : DLP projection● Selective solidification of a tank of liquid● Projector to solidify object layers one completecross-section at a time
12Theory : Polyjet matrix● Forms object layers by emitting liquidphotopolymer from an inkjet-style, multi-nozzel print head● Each layer is printed a powerful UV light isthen used to set it solid before the next layer isprinted● up to 14 of 120 potential materials to be printedat the same time
14Binder jetting● creates object layers by selectively sticking togethersuccessive layers of a powdered build material● a glue or binder is jetted from an inkjet style printhead to stick together successive powder layers● gypsum-based composite● build objects by sticking together plastic powders,sand or even metals.● final object is used as a mould in 3D sandcasting,with molten liquid metal poured into it
16Application : Industrial uses● Rapid prototyping : Car and other industrialproduct design● Rapid manufacturing : Production within notime● Mass customization : Every inch Customization● Mass production
17Prototype of Audi car using 3D PrinterFig 5. Prototype