UNIT -I INTRO to additive manufacturing, types and applications

it is related to additive manufacturing.
types also

1. Types of AM Technology AS Per ISO standards, AM divides the techniques used to create the layers into seven categories, of which the first four on the list are suitable for metals . Binder jetting Directed Energy Deposition Powder Bed Fusion Sheet Lamination Material Extrusion Material Jetting Vat Photo Polymerization

2. CNC MACHINING VS ADDITIVE MANUFACTURING

3. CNC MACHINING VS ADDITITIVE MANUF.

4. Binder Jetting Unique in AM in that it does not use heat during the materials fusing process. A binding liquid or binder is selectively deposited, which joins the powder material together to form the 3D part. Depending on the type of powder, the system being used, or customer application requirements determines the selection of the kind of binder.  The process starts with the powder material being spread over the build platform using a roller and the print head deposits the binder on top of the powder where specified. The build platform lowers to allow for the next layer, and the process repeats until the item is complete. Any unbound powder gets removed.

5. Figure- Binder jetting

6. Binder jetting

7. Binder Jetting

8. Advantages of Binder Jetting Ability to make parts with a range of different colors Uses a range of materials: metal, polymers, and ceramics Faster AM process No warping or shrinking of parts Less waste by reusing any unused powder Features a two-material method that allows different binder-powder combinations

9. Disadvantages of Binder Jetting Parts require post-processing which adds significant time to the overall process Low part strength, not always suitable for structural parts Less accurate then Material Jetting

10. Directed Energy Deposition (DED) DED creates   3D objects by melting and depositing either powder-based or wire-based materials from a focused thermal energy source, including laser, electron beam, or plasma arc. While the process can make metal, ceramic, and polymer parts, it is mainly used for metal parts and in more hybrid manufacturing where the substrate bed is moveable to create complex shapes. DED is also referred to as laser metal deposition (LMD), 3D laser cladding, or direct light fabrication because of the different energy sources uses and final use . Lastly, based on how the process works, it’s mainly used for repairing or reconditing existing parts by adding material where needed.

11. Advantages of DED Strong and dense parts Fast build rates Reduction in material waste Range of material selection: metal, ceramic, and polymer Materials are easily changed out Ability to make parts with custom alloys Parts built to near net shape Capability to build larger parts

12. Disadvantages of DED Capital cost for systems are high Parts have lower resolution resulting in poorer surface finish, requiring secondary processing Support structures are not usable during the build process

13. Powder Bed Fusion (PBF) PBF has four categories of energy sources , laser fused, electron beam fused, fused with agent and energy, and thermally fused. The energy source melts either plastic or metal powder particles, which solidifies and fuses together in a pattern to make the object. The powder bed fusion process uses two chambers, the build chamber and powder chamber, and a coating roller. To create the objects, the coating roller moves and spreads the powder material across the build chamber to deposit a thin layer of powder. Some PDF processes will use a scrapper, blade, or leveling roller after the coating roller to ensure the thickness of the material top layer is uniform.

14. Next, the energy source melts the deposited top layer of the metal powder base. When that layer has been scanned and fused, the build platform is incrementally lowered down, simultaneously the powder chamber is raised by the same, and the process repeats until the object completed. Advantages of PBF Low cost of machines No or minimum support structures needed for the build Variety of material selection Multiple materials can be used Capable of recycling powder

15. Disadvantages of PBF Slow and long print time Additional post-processing time Weaker structural properties Variations of surface texture quality Support build plate may be needed to avoid warping Speed of the print process can determine if the powder is recyclable Thermal distortion, mainly for polymer parts Machines use a lot of energy to create parts

16. Sheet Lamination AM that builds 3D objects by stacking and laminating thin sheets of material through bonding, ultrasonic welding, or brazing. To create the final shape of the object, laser cutting or  CNC machining  is used. Of all the AM technologies, this produces parts with the least additive resolution or amount of detail but provides low cost and faster manufacturing time for quick prototyping using readily available, low-cost material.

17. Sheet Lamination Sheet lamination can be categorized into seven types: Laminated Object Manufacturing (LOM) Selective Lamination Composite Object Manufacturing (SLCOM) Plastic Sheet Lamination (PSL) Computer-Aided Manufacturing of Laminated Engineering Materials (CAM-LEM) Selective Deposition Lamination (SDL) Composite Based Additive Manufacturing (CBAM) Ultrasonic Additive Manufacturing (UAM) While the types of sheet lamination differ slightly, the overall principle is the same. The process starts with a thin sheet of material being fed from the roller or placed onto the build platform. The next layer may or may not be bonded to the previous sheet, depending on the process. Layering continues until it achieves the full height. Removal of the print block and all the unwanted outer edges complete the object.

18. Advantages of sheet lamination Relatively low cost Larger working area Full-color prints Integrates as hybrid manufacturing systems Ease of material handling Ability to layer multiple materials No support structures needed In some sheet lamination Depending on technique type used, the material state remains unchanged Faster print time, but does require post-processing

19. Disadvantages of sheet lamination Layer height can’t be changed without changing the sheet thickness Finishes can vary depending on the material and could require post-processing Limited material options available Removal of excess material after the laminating phase can be difficult and time-consuming Can generate more waste in comparison to other AM methods Hollow parts are challenging to produce in some types of sheet lamination Bonding strength is dependent on the laminating technique used

20. Material Extrusion The most popular AM process in terms of availability for general consumer demand and quality, uses a continuous filament of thermoplastic or composite material to construct 3D parts. The material in the form of plastic filament fed through an extruding nozzle, where it heated and then deposited onto the build platform layer by layer.

21. Advantages of Material Extrusion Wide selection of print material Easily understandable printing technique User-friendly method of print material change Low initial and running costs Faster print time for small and thin parts Printing tolerance of +/- 0.1 (+/- 0.005″) No supervision required Small equipment size Low-temperature process

22. Disadvantages of Material Extrusion Visible layer lines Extrusion head in continuous motion or the material bumps up Supports may be required Weak part strength along Z-axis Increased print time with finer resolution and wider areas Susceptible to warping and other temperature fluctuation issues Toxic print materials

23. Material Jetting A process where droplets of wax-like materials are selectively deposited on a build platform. The material cools and solidifies, allowing layers of materials to be placed on top of each other. After the build, support structures are either mechanically removed or melted away.

24. Advantages of Material Jetting Material jetting can achieve outstanding accuracy and surface finishes Parts are good for use in patterns for casting Disadvantages of Material Jetting Limited number of wax-like materials available Parts are fragile because of wax-like materials Slow build process

25. Vat Photo Polymerization The process used to cure photopolymer liquid resin in a vat layer by layer, turning it into hard plastic parts using an ultraviolet (UV) laser. The three most common types of this technology include Stereolithography, Digital Light Processing (DLP), and Continuous Digital Light Processing (CDLP)

26. Advantages of Vat Photo Polymerization High level of accuracy and good finish Relatively quick process Large build areas Disadvantages of Vat Photo Polymerization Relatively expensive Lengthily post-processing time and removal from resin Limited to photo-resins materials Can still be affected by UV light after print May require support structures and post-curing for parts to be strong enough for structural use

27. Aerosol printing A very interesting process with a high potential is called aerosol printing. It was developed and launched as Maskles Mesoscale Materials Deposition (M3D) by Optomec , NM, USA. A stream of very fine droplets ( aerolsols ) is generated, loaded with ultra fine particles with diameters in the nanometer range, and guided to the surface of a substrate. Here, the aerosols are deposited according to a CAD designed pattern. The liquid phase is vaporized, leaving the particles in place.

28. Aerosol printing The particles may consist of any kind of functional inks, metals, ceramics, plastics, or even living cells. Depending on the kind of material, a post treatment by laser may be needed. Aerosol printing is a very promising process for electronic devices as well as for tissue engineering. As it is currently suitable only for 2½ D surface texturing and objects (at least now) and not for real 3D parts, some do not regard it a real AM process.

29. Bio plotter The 3D Bioplotter , which is a registered trademark of Envisiontec , Marl, Germany, allows to process a wide variety of materials from plastics, such as polyurethane or silicone, to bone materials such as hydroxyapatite, and drugs such as PCL (polycaprolactone3) or materials such as collagen or fibrin for organ printing or soft tissue fabrication. Up to five materials can be processed using either a heated or a cooled dispenser unit that is operated by a 3-axis plotter. Depending on the material, the system uses different hardening processes such as precipitation, phase transition (liquid to solid), or two-component reaction. Some materials need post processing such as sintering