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3D PRINTING #1 (Material Extrusion/"FDM" (PROS (Cheap + fairly…
3D PRINTING #1
What is 3D Printing?
- The process of making a physical object from a three-dimensional digital model, typically by laying down many thin layers of a material in succession
- The layers are usually about 0.1mm - 0.2mm thin
- We can already 3D print in hundreds of materials including plastics, metals + ceramics
- There are different 3D printing technologies, with ISO/ASTM being the 'standard'
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Material Extrusion/"FDM"
- A type of 3D printing that involves squirting out a semi-solid
- Most common form of 3D printing
- FDM means Fused Deposition Modelling, + it's a term trademarked by Stratasys, an American manufacturer of 3D printers. They regularly sue people who call their printers by the same name
- Common materials used include thermoplastics, like ABS [the plastic we see everywhere]. This means we're printing w something we already use a lot
- Can also use PLA [a bioplastic: can make things that will biodegrade], nylon, PETG + TPU
- Composite materials include PLA or ABS mixed w wood, metal or carbon fibres to make other types of materials
PROS
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- Widely accepted as the simplest way to 3D print
- Material flexibility: can use a wide variety of materials
- Scalability: can be easily scaled to any size
- Can make semi-solid objects: lattice pattern saves a lot of material
- Good cost-to-size ratio: can make FDM printers bigger + less expensive due to low-cost parts and simple designs
CONS
- Creates a weak point in the print where each layer is joined, making prints less sturdy
- Raw surface quality is rough, with significant layering. However, this can be improved via vapour honing [using solvents in the air, computer controlled, to make it smooth]
- Part quality/detail: bc the material must be extruded in layers + has a thickness predetermined by the nozzle, high detail prints are hard to achieve
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Material Jetting
- A type of 3D printing that involves spraying a photopolymer resin from multiple print head nozzles, then setting each layer solid with a UV light before adding the next
- Often used to make medical models, e.g in China there's a company that prints copies of patients' organs before surgery
PROS
- Great surface quality + accuracy
- Can be used to create full-colour, multi-material 3D prints, because it's possible to spray different materials + change what you're spraying at every layer
- Can print parts in a glossy or matte setting
CONS
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- Best for non-functional prototypes, bc they have poor mechanical properties
- Material jetting materials are photosensitive + their mechanical properties degrade over time
Binder Jetting
- A type of 3D printing that involves spraying a binder onto successive layers of powder
- Materials commonly used include metals, sand + ceramics that come in granular form
- Can be used to make full-colour prints from gypsum or plastic powders by jetting coloured inks in addition to the binder
- Can be used to make sand casting molds
- Can be used to make 99.9% metal objects via a multi-stage process
PROS
- Can manufacture very large parts + complex metal geometries bc it isn't limited by thermal effects like warping
- Produces metal parts + full-colour prototypes at a fraction of the cost of material jetting + DMLS/SLM
CONS
- Limited material selection compared to other 3D printing methods
- Can only print rough details bc the parts are v brittle
Powder Bed Fusion [SLS, DMLS, EBM]
- Type of 3D printing that involves using a laser or electron beam to sinter/fully melt particles of powder
- Selective Laser Sintering [SLS] makes objects out of nylon + other plastics, as well as composites [e.g nylon + aluminium "alumide" is often used nowadays]
- Direct Metal Laser Sintering [DMLS] or Electron Beam Melting [EBM] can make industrial parts in copper, steel, aluminium or other metals
PROS
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- Large range of material options
- Powder acts as integrated support structure
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