Rapid prototyping technologies,applications &part deposition planning 2

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Rapid prototyping technologies,applications &part deposition planning 2

  1. 1. RAPID PROTOTYPING TECHNOLOGIES,APPLICATIONS &PART DEPOSITION PLANNING Johnbin johnson S7 ME 26 1
  2. 2. CONTENT • • • • • HISTORY INTRODUCTION PRINCIPLE & FLOWCHART WHY RAPID PROTOTYPING? RP PROCESSES STEREOLITHOGRAPHY FUSED DEPOSITION MODELING LAMINATED OBJECT MANUFACTURING SELECTIVE LASER SINTERING • PART DEPOSITION PLANNING ACCURACY OF RP PARTS PART DEPOSITION ORIENTATION • • LIMITATIONS APPLICATIONS 2
  3. 3. HISTORY • First phase-Manual prototyping by skilled craftsman (old practice) • Second phase-soft prototype modeled by 3D Curves & surfaces (mid 1970) • Third phase-rapid prototyping (1980) 3
  4. 4. INTRODUCTION • PROTOTYPE A prototype is a model used to test and evaluate a design .it is just a test version of an experiment or machine .Before the start of full production a prototype is usually fabricated & tested . • RAPID PROTOTYPING Rapid Prototyping (RP) can be defined as a group of techniques used to quickly fabricate a scale model of a part or assembly using three-dimensional computer aided design (CAD) data. 4
  5. 5. PRINCIPLE & FLOW CHART 5
  6. 6. PRINCIPLE & FLOW CHART (con..) • • First process in RP is generation of 3D model of the product .Commonly used 3D CAD systems for this are o Pro/E o UG o CATIA o IDEAS Second process is tessellation of 3D model .Basically it is generation of layer model .A STL file is created after tessellation 6
  7. 7. PRINCIPLE & FLOW CHART (con..) • In next process slicing of model is done by various slicing softwares like MeshLab openRP Admesh • Generated sliced data is stored in standard data formats like SLC or CLI. • The next stage of process is making of physical model in which we use a RP system software. • RP system software generates laser scanning path in which material deposition should occur. 7
  8. 8. PRINCIPLE & FLOW CHART (con..) • Final stage is post processing or finishing of part in which following process will occur o Cleaning o Polishing o Painting o Milling ,grinding etc..  Prototype is then tested &suggested changes are once again incorporated during the solid modeling stage.
  9. 9. TESSELLATION & SLICING • Surfaces of CAD model are piecewise approximated by a series of triangles.
  10. 10. TESSELLATION & SLICING • In slicing the CAD model is divided into number of layers .slice thickness is important thing we should consider during this stage.
  11. 11. Why Rapid Prototyping? • The Prototype gives the user a fair idea about the final look of the product. • To increase effective communication between user & designer. • Decrease development time. • Increasing number of variants of products. • It is easier to find the design flaws in the early developmental stages. • cost effective.
  12. 12. PROCESSES • One method of classification of RP process is based on state of aggregation of their original material.
  13. 13. STEREOLITHOGRAPHY • In this process liquid resin which forms a solid polymer is exposed to UV rays. • Main parts of SL machine is a build platform (mounted on vat) & argon ion laser or UV Helium-cadmium laser. • Laser scans first layer & platform is then lowered equal to one slice thickness. • A dip-delay is provided for the liquid polymer to settle to a flat & even surface. • Scanning speeds ~ 500 to 2500 mm/s. • Once complete part is deposited ,it is removed from vat & excess resin is drained.
  14. 14. STEREOLITHOGRAPHY (con) stereolithography
  15. 15. STEREOLITHOGRAPHY (con) A part produced by sterelithography SL machine
  16. 16. FUSED DEPOSITION MODELING • Main part of a FDM is a movable (x-y) nozzle. • Molten polymeric material comes through this nozzle which gets deposited on the substrate. • Workhead is controlled in the x-y plane during each layer. • Build material is heated slightly above its melting point so it can solidifies easily. • One layer will cold welds to previous layer. • Part is fabricated from the base up, using a layer-by-layer procedure.
  17. 17. FUSED DEPOSITION MODELING (con..) Fused Deposition Modeling
  18. 18. LAMINATED OBJECT MANUFACTURING • Profiles of object cross section are cut from paper or another material by using laser. • Power full CO2 Laser is used for this purpose. • Paper is unwound from feed roll. • It is bonded to previous layer with use of a heated roller. • Heated roller activates a heat sensitive adhesive . • Slices are cut by laser. • Waste paper is wound on a take up roll. • Once one slice is completed platform is lowered & same process is repeated.
  19. 19. LAMINATED OBJECT MANUFACTURING LOM process
  20. 20. SELECTIVE LASER SINTERING • In SLS same process as that in LOM is used. • But in SLS fine polymeric powder like polycarbonate is used. • Powder is spread over substrate using a power feed roller. • CO2 laser beam sinters heat‑fusible powders. • Grains having direct contact with laser beam fuse with previous layer. • Then bed is lowered & In areas not sintered, the powders are loose and can be poured out of completed part
  21. 21. SELECTIVE LASER SINTERING SLS process
  22. 22. PART DEPOSITION PLANNING • It is very important because it decides • part accuracy • surface quality • building time • cost of part • Accuracy of a part depends upon tessellation & slicing. • Tessellation errors can be reduced by reducing size of triangles. • Slicing of CAD model with a very small slice thickness leads to large build time . • At the same time if large slice thickness is chosen, the surface finish is very bad . • Slicing errors can be reduced by using adaptive slicing
  23. 23. PART DEPOSITION ORIENTATION • Selection of suitable part deposition orientation can reduce part building time ,cost etc.. • But it is difficult & time consuming because we should consider various processes. • A multi objective genetic algorithm is proposed for part deposition planning.
  24. 24. LIMITATION • Poor surface finish due to Staircase appearance caused due to layering . • It may not be suitable for large sized applications. • Limited strength. • Some important developmental steps could be omitted to get a quick and cheap working model. • Mechanical performance of the fabricated parts is limited by the materials used in the RP process . • Shrinkage and distortion of RP parts.
  25. 25. APPLICATION • Applications of rapid prototyping can be classified into three categories: 1. Design . 2. Engineering analysis and planning . 3. Tooling and manufacturing. • Designers are able to confirm their design by building a real physical model in minimum time using RP • It will help them to visualize the object, Early detection of design errors , Reduced lead times etc.. • In Engineering analysis and planning we will be able to do stress analysis ,flow analysis ,mock-up etc..
  26. 26. APPLICATION • In tooling application Pattern is created by RP and the pattern is used to fabricate the tool. • RP is commonly used in industries like automotive ,aerospace, jewelry ,biomedical etc…
  27. 27. nk yo u Tha

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