Solid based RP systems FDM

Solid based RP systems FDM

1. UNIT 2 SOLID BASED RAPID PROTOTYPING SYSTEMS

2. Introduction Solid Based Additive Manufacturing systems utilise solids as the primary medium to create the part or prototype.

3. FUSED DEPOSITION MODELLING(FDM)

4. Company Stratasys Ltd developed AM systems based on Fused Deposition Modelling technology. The technology was first developed by Scott Crump in 1988 Patent was awarded in USA in 1992. Stratasys introduced first FDM AM machine in 1992. Its headquarters is in USA.

5. Products/Models Stratasys manufactures 3D printing equipment and materials that create physical objects directly from digital data. Its system range from affordable desktop 3D printers to large and advanced 3D production systems making 3D printing more accessible than ever.

6. Idea series 3D printers

7. Idea series 3D printers Stratasys ' Idea Series 3D printers are compact, light and affordable desktop 3D printers that enhance users' design capability at the push of a button. With FDM technology, they liberate customers creativity and accelerate the design process. These 3D printers bring professional 3D printing to consumers desktops or small team workspaces.

8. Specifications of idea series 3d printers

9. Design series 3d printers

10. Design series 3d printers Stratasys ' Design Series 3D printers are built as affordable and office- friendly AM systems. They are meant primarily for concept modelling, creating product replicas and some functional testing capabilities. Under the Design Series, there are two categories of 3D printers Precision3D printers Performance 3D printers.

11. Design series 3d printers Precision 3D printers are based on PolyJet 3D printing technology. On the other hand, there are three machines in the Performance 3D printers. Series Dimension 1200es Dimension Elite Fortus 250mc These are powered by FDM technology.

12. Design series 3d printers Performance 3D printers use ABS plus thermoplastic to produce the 3D models. The parts are durable and dimensionally stable, making them perfect for tough testing. The raw materials are affordable, allowing frequent iterative 3D modelling.

13. Design series 3d printers

14. Production series 3D PRINTERS

15. Production series 3D PRINTERS Stratasys ' Production Series 3D printers can create large products on the factory floor, having a build size larger than the office-friendly Performance Series or the desktop Idea Series. They can create low- volume assembly fixtures and jigs directly from computer-aided design (CAD) data. Thus they can be used for prototyping, tooling and digital manufacturing for designers and engineers.

16. Production series 3D PRINTERS There are three FDM machines in the Production Series Fortus 380mc Fortus 450mc Fortus 900mc The Fortus 900mc 3D Production System offers the use of the widest range of FDM materials. They include high- performance thermoplastics for durable and accurate parts with strong mechanical , chemical and thermalproperties .

17. Production series 3D PRINTERS

18. Materials Stratasys Ltd. offers a wide range of AM materials, including clear, rubberlike and biocompatible photopolymers for the PolyJet machines. Tough high-performance thermoplastics for the FDM machines. The wide range of materials enables designers and engineers to build practically anything at any stage of the product development cycle, from fast and affordable concept modelling, to detailed, realistic and functional prototyping, to certification testing, and to agile, low-risk production.

19. Materials Furthermore, FDM thermoplastics are used to build tough, durable parts that are accurate, repeatable and stable over time. Materials used include ABS, polycarbonate, FDM Nylon-12 and ULTEMTM, a thermoplastic polyetherimide (PTI) that has good thermal resistance, high strength and stiffness, and broad chemical resistance.

20. PROCESS In Stratasys ' patented process,' a geometric model of a conceptual design is created on CAD software which uses .STL or Initial Graphics Exchange Specification (IGES) files. It can then be exported from the CAD software into the AM systems where it is processed using Insight software or CatalystEX software, which automatically generates supports. Within this software, the CAD file is sliced into horizontal layers after the part is oriented for the optimum build position, and any necessary support structures are automatically detected and generated.

21. PROCESS The slice thickness can be set manually anywhere between 0.127 and 0.330 mm (0.005–0.013 in.) depending on the needs of the models and the machine. Tool paths of the build process are then generated and downloaded to the FDM machine.

22. PROCESS Modelling material is in the form of a filament very much like a stiff fishing line and is stored in a cartridge or spool. The filament is fed into an extrusion head and heated to a semi-liquid state. The material is then extruded through the head and then deposited in ultra-thin layers from the FDM head, one layer at a time. Since the air surrounding the head is maintained at a temperature below the material's melting point, the exiting material quickly solidifies.

23. PROCESS Moving on the x-y plane, the head follows the tool path generated by the software, fabricating the desired layer. When the layer is completed, the base plate moves down one layer and the head starts creating the new layer. Two filament materials are dispensed through a dual tip mechanism in the FDM machine a primary material is used to produce the model geometry A secondary material, or release material, is used to produce the support structures.

24. PROCESS The release material forms a bond with the primary modeller material and can be broken away or washed away with detergent and water upon completion of the 3D models

25. SCHEMATIC DIAGRAM OF FDM PROCESS

26. Strengths Fabrication of functional parts : Able to fabricate prototypes Fully functional parts can be fabricated using ABS They have 85% of the strength of the injection moulded parts . This is especially useful in developing products that require quick prototypes for functional testing.

27. Strengths Minimal wastage : The FDM process builds parts directly by extruding molten semi-liquids onto the model . material wastages are minimised There is little need to clean up the model after it has been built.

28. Strengths Ease of support removal : Breakaway support materials Soluble support materials They can be easily snapped off or simply washed away in a water-based solution . Can get finished products very quickly There is very little or no post processing

29. Strengths Ease of material change : Build materials, supplied in spool or cartridge form easy to handle can be changed readily when the materials in the system are running low. This keeps the operation of the machine simple.

30. Strengths Large build volume : FDM machines, especially the Fortus 900mc, offer a larger build volume than most of the other AM systems available .

31. Weaknesses Restricted accuracy: Parts built with the FDM process usually have restricted accuracy due to the shape of the material used, that is, the filament form . Typically, the filament used has a diameter of 1.27 mm and this tends to set a limit on how accurate the part can be achieved . However the newer FDM machines have made significant improvements in mitigating this issue by using better machine control .

32. Weaknesses Slow process: The building process is slow, as the whole cross- sectional area needs to be filled with building materials. Building speed is restricted by the extrusion rate or the flow rate of the build material from the extrusion head.

33. Weaknesses Unpredictable shrinkage: As the build material cools rapidly upon deposition from the extrusion head, there will be thermal contraction and stresses induced. As such, shrinkages and distortions in the model are common and are usually difficult to predict. With experience, users may be able to compensate for these issues by adjusting the process parameters of the machine.

34. Applications (1) Models and prototypes for conceptualisation and presentation: FDM 3D printers can create models and prototypes for new product design and testing and build finished goods in low volumes . (2 ) Educational use: Educators can use FDM technology to elevate research and learning in science, engineering, design and art . (3) Customisation of 3D models: Hobbyists and entrepreneurs can use FDM to manufacture products in their homes creating gifts, novelties , customised devices and inventions.