PRESENTATION

WORKSHOP TECHNOLOGY 2

JJ204

GROUP MEMBERS

KATHIRAVAN S/O PARAMASIWAN

NAAVINDRA PRASAD S/O GANESAN

SIM KAH TIANG

WHAT IS 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 or "additive layer manufacturing" technology.

• Rapid prototyping is a revolutionary and powerful technology with wide range of appilications

• The process of prototyping involves quick building up of a prototype or working model for the purpose of testing the various design,features,ideas,concepts,functionality,output and performance

HISTORY OF RAPID PROTOTYPING

IN SIXTIES

• The history of rapid prototyping can be traced to the late sixties, when an engineering professor,HERBERT VOELCKER,questioned himself about the possibilities of doing interesting things with the computer controlled and automatic machine tools

• These machine tools had just started to appear on the factory floors then

• VOELCKER was trying to find a way in which the automated machine tools could be programmed by using the output of a design program of a computer

IN SEVENTIES• VOELCKER developed the basic tools of

mathematics that clearly describe the three dimensional aspects and results in the earliest theories of algorithmic and mathematical theories for solid modeling

• These theories form the basis of modern programs that are used for designing almost all things mechanical,ranging from the smallest toy car to the tallest skyscraper.

• VOELCKER's theories changed the designing methods in seventies

IN EIGHTIES

• However, in 1987,CARL DECKARD,a reseacher form the university of TEXAS,came up with a good revolutionary idea.

• He pioneered the layer based manufracturing,wherein he thought of building up the model layer by layer

• He printed 3D models by utilizing laser light for fusing metal powder in solid prototypes,single layer at a time

• DECKARD developed this idea into a technique called "Selective Laser Sintering"

PRESENT DAYRAPID PROTOTYPING

• Today,the computer engineer has to simply sketch the ideas on the computer screen with the help of a design program that is computer aided

RAPID PROTOTYPING IS ALSO KNOWN AS

• Solid freeform fabrication(SFF)• Freeform fabrication(FF)• Digital fabrication• Automated freeform fabrication(AFF)• 3D printing• Solid imaging• Layer based manufacturing• Laser prototyping• Additive manufacturing

ADVANTAGES OF RAPID PROTOTYPING

Time Savings• By eliminating the time needed to produce molds,

patterns and special tools required for conventional modeling, rapid prototyping reduces time between initial design and analysis.

• An accurate model is quickly available for testing form, features, performance and usability.

• Rapid prototyping is a highly automated process that enables designers to quickly modify products in line with feedback.

• The time savings can help organizations gain competitive advantage by bringing new products to market quickly, ahead of competitors.

Cost Reduction• Rapid prototyping helps to reduce the costs of

product development.There is no need to develop special tools for each new product.

• Rapid prototyping uses the same CAD and printing equipment each time. The automated prototyping process also reduces staff costs.

• The costs of waste are lower, because the prototyping technique only adds modeling material where needed. Conventional prototyping techniques create waste through cut-off material or chippings as the tools create the finished m

Others advantages:• CAD data files can be manufactured in hours

• Tool for visualization and concept verification

• Prototype used in subsequent manufacturing operations to obtain final part

• Tooling for manufacturing operations can be operatoins

SUBTRACTIVE PROCESSOF RAPID PROTOTYPING

• Subtractive process is the prevalent process in the history of model making.

• Model makers once utilized materials like clay and wood or other hard material,to whittle,carve,or sculpt a model component.

• A complex part could be made in a number of pieces and assembled to create the final product.

• The excess material was basically chiseled,cut and sanded to expose the design within the carving medium.

• Once a part was roughed out in the desired material,hand finishing,applying colors,textures and graphics allowed model makers to achieve a unique part that often closely mimicked the desired future product.

• Architectural model makers use laser cutting technology to precisely incise materials like foam core,high density papers and others material to replicate panels used in the construction of structural models.

• Product design model makers may use molds and castings,CNC routers or milling machines to electronically carve parts out of the desired medium

ADDITIVE PROCESS OF RAPIDPROTOTYPING

• Additive process refers to a class of manufracturing processes,in which a part is build by adding layers of material upon one anothers.

• These processes are inherently different from subtractive processes or consolidation processes.

• Subtractive processes,such a milling ,turning or drilling,use carefully planned tool movements to cut away material from a workpiece to form the desired part.

• Consolidation processes, such as casting or molding,use custom designed tooling to solidify material into the desired shape.

• Additive processes,on the other hand,do not require custom tooling or planned tool movements.

• Instead,the part is construsted directly from a digital 3-D model created through Computer Aided Design(CAD) software.

• The 3-D CAD model is converted into many thin thin layers and the manufacturing equipment uses this geometric data to build each layer sequentially until the part is completed.

• Due to this approach,additive fabrication is often referred to as layered manufacturing.direct digital manufacturing or solid freeform fabrication.

VIRTUAL PROCESS

• Virtual prototyping is becoming a cost-effective method used in testing new products and system.

• It is an integral part of current rapid prototype Shenzhen methods wherein virtual designs created from computer aided (CAD) or animation modeling software are used and then transformed into cross sections in a still virtual environment.

• A special machine is then used to create each virtual cross section in then takes physical form layer until an identical prototype model is created.

• The whole process enables the virtual model become a physical model with corresponding identical features

FUSED DEPOSITIONPROCESS

• FDM is the second most widely used rapid prototyping technology after stereolithography.

• A plastic filament is unwound from a coil and supplies material to an extrusion nozzle.

• The nozzle heated to melt the plastic and has a mechanism which allows tha flow of the melted plastic to be turned on and off.

• The nozzle is mounted to a mechanical stage which can be moved in both horizontal and vertical directoins.

• The concepts can best be described as a hot glue gun mounted in place of the cutter on 3 axis NC mill

• As the nozzle is moved over the table in the required geometry,it deposits a thin bead af extruded plastic to form each layer.

• The plastic hardens immediately after being squirted from the nozzle and bonds to the layer below.

• The entire system is contained within a chamber which is usually kept warm during the build process to prevent internal stresses from distorting the geometry

STEREOLITHOGRAPHY

• Stereolithography builds epoxy parts one layer at a time by tracing a laser beam on the surface of a vat of liquid photopolymer

• The material solidifies wherever the laser beam strikes the surface of the liquid .

• After a layer is completed,the part is lowered a small distance into film of resin,and a second layer is traced right on top of the first .

• The layers are stacked sequentialy to form a complete,three-dimensional object.

• At this point in the process,parts are cleaned and post-cured.

SELECTIVE LASER PRINTING

• Thermoplastic powder is spread by a roller over the surface of the part bed.

• The piston in cylinder moves down on object layer thickness to accommodate each new layer of powder.

• The powder delivery system is similar in function to the part bed.

• Here,a piston moves upward incrementally to supply a measured quantity of powder for each layer.

• The fabrication chamber is maintained at a temperature just below the melting point of the powder so that heat from the laser need only elevate the temperature slightly to cause sintering.

• This greatly speeds up the process.

• A computer-directed infrared laser is then traced over the surface of the powder to seletively melt and bond a cross section of part to form one layer of the object.

• The process is repeated layer by layer until the entire object is fabricated.

BALLISTIC PARTICLEMANUFACTURING

• Ballistic particle manufacturing utilizes ink jet or droplet based manufacturing techniques,where it builds the models by firing micro-droplets of molten wax material from a moving nozzle or jet onto a stationary platform,the platform then lowers and the process is reapeted for each layer of the model.

LAMINATED OBJECTMANUFACTURING

• 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. Objects printed with this technique be additionally modified by machining or drilling after printing.

• Typical layer resolution for this process is defined by the material feedstock and usually ranges in thickness from one to a few sheets of copy paper.

SOLID GROUNDCURING

• Solid ground curing (SGC) is a photo-polymer-based additive manufacturing (or 3D printing)technology used for producing models, prototypes, patterns, and production parts, in which the production of the layer geometry is carried out by means of a high-powered UV lamp through a mask.

• As the basis of solid ground curing is the exposure of each layer of the model by means of a lamp through a mask, the processing time for the generation of a layer is independent of the complexity of the layer

BASIC METHODOLOGYOFRAPIDPROTOTYPING

• A CAD model is constructed,then converted to STL fomat.The resolution can be set to minimize stair stepping.

• The RP machine processes the STL file by creating sliced layers of the model.

• The first layer of the physical model is created.The model is then lowered by the thickness of the next layer,and the process is repeated until completion of the model.

• The model and any supports are removed.The surface of the model is then finished and cleaned

RAPID TOOLING USES

• Producing tooling directly from CAD models is regarded as an important method for reducing the cost and time to market of new products.

• Rapid tooling (RT) typically describes the process in which a rapid prototyping(RP) model is used as a pattern to quickly create a mold or in which the rapid prototyping process itself is used to fabricate a limited volume of tool prototypes.

• It describes in detail how a colorful silicone keypad can be made in a short time after the design of the mold is completed.

THANK YOU