Fichas
Additive Manufacturing
Fichas del conjunto (48)
- 1Why is the orientation of parts in the build chamber important?Want to fit as many parts possible into a single print
Which surface is most important?
- Surfaces where support material has to be removed or which are in contact with the build platform will not be smooth
Warpage
- Want to minimise cross sectional area of each layer to reduce stresses and reduce warpage
Save support material
- Can the part support itself in a different orientation? - 2Stereolithography (SLA)Selectively curing monomer with laser
Parts built on platform which lowers the part into tank by the layer thickness
Ceramic powder can be dispersed in the monomer to make ceramic parts - 3SLA AdvantagesRound the clock operation
- Only have to stop for loading and unloading
Range of build volumes
Good / excellent accuracy
- Two photon polymerisation could provide nanometer resolution
One of the best AM processes for surface finish
Wide range of materials - 4SLA DisadvantagesRequires:
Support structures
Post processing
Post curing - 5SLA ApplicationsModels for concept visualisation, packaging & presentation
Prototypes
Parts for prototype tooling and low volume production tooling
Patterns for investment casting - 6PolyjetInkjet printing for direct printing of monomers
Cure monomers using UV light - 7Continuous Inkjet PrintingContinuous stream of droplets
Droplets deflected onto surface or down recycling gutter by a charge electrode
Very Fast
Low Quality - 8Drop on Demand Inkjet PrintingDroplet only generated when needed
Piezo transducer deforms and squeezes nozzle to produce droplet
or
Thermo transducers form air bubble in nozzle which separates the droplet from the ink - 9Inkjet Printing AdvantagesLarge print volume
High quality
- Layers can be 16um thick
High accuracy
Fast process speed
- Doesn't require draining, resin stripping, polishing etc.
Smooth surface finish
- Not in contact with anything
Wide range of materials
- Tough acrylics
- Polypropylene like plastics
- Rubber like materials
Can combine materials
- Only AM process which can achieve this in the same print job - 10Inkjet Printing DisadvantagesPost processing
- Removal of support
- Water jet can damage fine structures
Support material is waste
- For a hollow part the support material could cost more than the part material - 11Inkjet PrintingConcept design
Casting applications
Custom Prosthesis design
Surgery simulation
Jewellery industry - 12Multijet PrintingLike objet
BUT MORE JETS
also prints polymer - 13Multijet Printing AdvantagesEfficient and easy to use
- Multiple jets allow fast and continuous deposition
High precision
- Best in class part quality
Cost effective
- Uses cheap thermo polymer material
Fast build time
- Model work volume (envelope) is singular defining factor
Office Friendly - 14EnvisionTEC's Perfactory Digital Light ProcessingNo laser, instead uses projector directed by a DLP through a lens
Shines into vat of material - 15DLP AdvantagesHigh build speed
- Fastest in AM market
- Floods area with light instead of scanning each point with a laser - 16DLP DisadvantagesLimited build time - Parts built from bottom of the build chamber and stuck to carrier platform
Finished product has to be peeled from platform
Cleaning and post-processing, sometimes post-curing are required - 17Fused Deposition Modelling (FDM)Heats filament to semi-liquid form
High quality systems have part & support material
Base moves down after each layer
Material wastage is minimum
careful heating of material is vital as relies on the material remaining solid to force the semi-solid material through the nozzle head - 18FDM AdvantagesFabrication of functional parts
- Uses same material as injection moulding
- Can achieve 85% strength of injection moulding
Minimal wastage
Ease of support removal
Ease of material change
Large build volume
Low cast raw material - 19FDM DisadvantagesRestricted accuracy due to filament form and nozzle size
Slow process
- Whole cross section has to be filled with material
- Restricted extrusion rate
- High material viscosity
Unpredictable shrinkage
- Cooled rapidly to room temperature
- Can lead to distortion
Delamination
- Weak bonding between layers - 20Solidscape Benchtop SystemDeposited as liquid, stored as solid
Precision milled every few layers to improve control and provide smooth surface for next layer - 21Solidscape Benchtop System ApplicationsWax patterns for casting small metal & ceramic parts
- 22Solidscape Benchtop System AdvantagesNo ash, residue or shrink
No post-processing or special equipment needed
High accuracy
Office friendly - 23Solidscape Benchtop System DisadvantagesVery limited materials
- Restricted to 3Z model (proprietary material formulated specifically for casting) - 24Selective Deposition Lamination (SDL)Paper 3D printing
LOM
- Paper Rolls
- Pre-applied adhesive
- Laser to cut
SDL
- Knife to cut
- Sheets of paper
- Dispenses adhesive - 25SDL AdvantagesLow cost
- Lowest price in industry taking into account material costs
High precision
Safe
- No lasers
- No toxic chemicals, powder or dust
Eco Friendly
- Can be recycled
High resolution in colour printing - 26LOM AdvantagesWide variety of materials
Fast build time
- Laser only scans outside/inside profile rather than whole cross section
- Good for large bulky products
High precision
- < 0.127mm
- As long as layer doesn't distort in lamination there is no distortion
- Laser doesn't cause shrinkage
No need for support structure
No post curing required
- Sheet materials not subject to physical/chemical changes - 27SDL DisadvantagesLow strength
Small build volume - up to A4 - 28LOM disadvantagesLaser power has to be precise to only cut current layer
Not well suited to thin walled structures
- Not sufficiently rigid to survive post processing
Part strength entirely dependant on adhesive strength of glue
- May not be able to undergo mechanical loading required by a prototype
Removal of all supports is labour intensive
- All been bonded with the same adhesive
- Done with wood carving tools - 29Ultrasonic ConsolidationUses aluminium foil
Osciallation between layer and substrate and forces applied in Z direction cause the oxide layer to breakdown and plastic deformation
Part is milled
Uses advantages of both AM and subtractive manufacturing (machining)
Complex 3D parts with
- Good surface finish
- High dimensional accuracy - 30Selective Laser Sintering (SLS)Large vat filled with powder
Adjacent tanks supply main tank with powder and allow for excess powder to be deposited by a leveller / wiper
Can have a hopper instead as a means of supplying powder
Mirror system used to control laser
Laser increases temperature of powder to melting point
Whole system can be enclose in a preheated cabinet to reduce required laser power - 31SLS MaterialsAny thermoplastic
Polystyrene for investment casting
Polymer coated sand to create mould for sand casting
Polymer coated metal
- Requires further debinding and consolidation process
PEEK
- Requires high T
- 2 x Stronger than nylon - 32SLS AdvantagesGood part stability
- Very controlled environment
- Inert gas to avoid oxidisation of polymer
Wide range of materials
- Anything which can be coated in a polymer
No support parts required
Little post processing
- Finish is reasonably fine
- May require particle blasting or sanding
No post-cure - 33SLS DisadvantagesLarge physical equipment size
High power consumption
Dusty environment
Powder not environmentally friendly - 34Selective Laser Melting (SLM)SLS - Polymer - 10um CO2 laser
SLM - Metal - 1um fibre / Nd:YAG laser
Powder fully melted rather than partially melted
Different inert environment needed
- Ar for Ti & Al - 35SLM AdvantagesHigh quality, metal parts
- Allows homogeneous build up of parts
- Large range of metal materials
Fast
- No post processing
- Heat treatment for large parts
High accuracy, resolution, precision
Complex parts - 36SLM Disadvantages- Large physical size
High power consumption
Slow build process compared to high speed machining
Wastage
- Powder adjacent to workpiece cannot be recycled due to degradation
- Fill build volume as much as possible to reduce waste - 37CJPInkjet printing binder on powder bed
Remaining powder supports structure
Loose powder vacuumed away after each layer
After build part can be infiltrated with wax, resin or urethane to add strength - 38CJP AdvantagesHigh Speed
Versatile
- Large range of industries
- Used throughout design process
- Can be infiltrated to form a variety of material properties - 39CJP DisadvantagesLimited function of parts
- Weak compared to SLS
Poor surface finish
- Post processing frequently required
Heavy components
- High binder density - 40Bio AM Scaffold should...Have appropriate mechanical properties to provide the correct stress environment for neotissues
Be porous & permeable to permit the ingress of cells and nutrients
Exhibit appropriate surface structure and chemistry for cell attachment - 41Bio AM Why AM?Traditional manufacturing techniques have problem on connecting the pores, porosity and pore shape and distribution control
Scaffolds made using traditional methods lack mechanical strength
Model can be generated form computer tomography data
AM can personalise scaffold to a patient - 42Extrusion FreeformingFDM
Low temperature deposition
- Freezing & phase seperation
Direct write assembling - Gelation
Paste extrusion - Solvent evaporation - 43Bone Repair Scaffolds < 10umEncourage cell adhesion and phenotype development
Provide dissolution - 44Bone Repair Scaffolds 10 - 100 umProvides room for division and mineralisation
- 45Bone Repair Scaffolds > 100 umProvide corridors for vascularisation
- 46Indirect Inkjet Printing Multiple MaterialsDry ceramic powder levelled by roller to provide thin layer
Ink jet printing head prints a layer of binder selectively on the loose powder - 47Indirect Inkjet Printing AdvantagesHigh speed of fabrication
Multiple materials - 48Indirect Inkjet Printing DisadvantagesLow shape and compositional resolution
Low composition flexibility
Low density
Low mechanical strength
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- Fichas sobre Additive Manufacturing, creado por tom8390 el 09/01/2015.
- Creado por
- tom8390
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