Lecture 1 - Introduction Flashcards
additive manufacturing
a process of joining materials to make objects from 3D model data, usually layer upon layer
3D printing
the fabrication of objects through the deposition of a material using a print head, nozzle, or another printer technlogy
What is the downside of complex microstructures in additive manufacturing?
Very difficult to achieve uniformity and therefore certification.
What are two differences between conventional and additive manufacturing?
Conventional manufacturing produces more scrap/waste and both have different material and mechanical properties.
What are the three types of manufacturing techniques?
- Subtractive
- Near net shape
- Additive
What is the general sequence of additive manufacturing?
- CAD and slice
- Convert to .STL file
- Transfer to AM machine and .STL file manipulation
- Machine setup (processing parameters selection)
- Build
- Postprocessing/removal
- Certification
- Application
What are the seven AM process categories?
- binder jetting
- directed energy deposition
- material extrusion
- material jetting
- powder bed fusion
- sheet lamination
- vat photopolymerization
binder jetting
an AM process in which a liquid bonding agent is selectively deposited to join powder materials. metal or ceramic powdered parts are typically fired in a furnace after they are printed.
directed energy deposition
an AM process in which focused thermal energy (laser, electron beam, plasma) is used to fuse materials by melting as they are being deposited.
material extrusion
an AM process in which material is selectively dispensed through a nozzle or orifice
material jetting
an AM process in which droplets of build material are selectively deposited (photopolymer, wax)
powder bed fusion
an AM process in which thermal energy selectively fuses regions of a powder bed. powder surrounding the consolidated part acts as support material for overhanging features.
sheet lamination
an AM process in which sheets of material are bonded to form an object
vat photopolymeriation
an AM process in which liquid photopolymer in a vat is selectively cured by light activated polymerization, converting exposed areas to a solid part
What are six benefits to additive manufacturing?
- One-of-a-kind item or small number parts
- Shape of object in computer form
- Complex shape and complex microstructures
- automated process planning
- generic tooling
- minimal human intervention
AM is the intersection of what three fields?
Materials Science, Mechanical Engineering, and Software/Machine Learning/Computer Science
What are the five traditional technologies of Materials Science?
- powdered metallurgy
- welding
- extrusion
- CNC machining
- lithography
What are the three enabling component technologies of Mechanical Engineering?
- lasers
- ink-jet printers
- motion control
Software/Machine Learning/Computer Science contributes what technology to AM
CAD (solids modeling)
What is the role of Materials Science in AM?
- Processing
- Structure
- Properties
- Performance
All forming characterization.
What is the accuracy of PBF?
10s of micrometers
PBF is the dominant AM technique for what materials?
metals, alloys, and ceramics
What are three advantages of PBF?
high level of complexity,
powder acts as support material, wide range of materials
What are typical materials of PBF?
plastics, metal and ceramic powders, sand, composite
What six techniques are included in PBF?
selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, selective heat sintering, multi-jet fusion
What is the speed typical for PBF (low, medium, high)?
Medium
Is powder in PBF cheap or expensive?
Expensive
What are the two common types of PBF?
Laser and EBM
What are the trace amounts of Helium for in EB-PBF?
to prevent static electron build-up
What is the main difference between laser and electron beam PBF?
Laser has a higher cooling rate
Laser spattering produces what in PBF?
Pores, which result in weaker material structure
What are four alternates names to DED?
Laser Metal Deposition, Laser Engineered Net Shaping, Direct Metal Deposition, Wire Arc Additive Manufacturing
What are five strengths of DED?
not limited by direction or axis
effective for repairs and adding features
multiple materials in a single part
highest single-point deposition rates
larger build volumes
What are typical materials for DED?
metal wire and powder, ceramics
How popular is DED?
it is the second most popular AM technique for metals
What is the disadvantage to DED?
Less dimensional accuracy (200 micron builds)
What are alternative names to binder jetting?
3D printing
ExOne
Voxeljet
What are four strengths to binder jetting?
full color printing
high productivity
wide range of materials
low temperature and residual stresses
What are five typical materials for binder jetting?
powdered plastic, metal, ceramics, glass, sand
What are two disadvantages to binder jetting?
low dimensional accuracy
postprocessing required
What are four characteristics to metal binder jetting?
equipment is cheap
extensive post-processing
geometry inaccuracy
often contains contaminations
What are four alternative names to material jetting?
Polyjet
Smooth Curvatures Printing
Multi-Jet Modeling
Projet
What are two varieties of material jetting?
jetting a photocurable resin and curing with UV light
jetting thermally molten materials that solidify at ambient temperatures
What are three strengths to material jetting?
high level of accuracy
full color parts
multiple materials in a single part
What are three typical materials for material jetting?
photopolymers, polymers, waxes
What are two alternative names to material extrusion?
fused filament fabrication
fused deposition modeling
What are four strengths to material extrusion?
inexpensive and economical
multiple colors
used in office environment
good structural properties
What are three typical materials?
thermoplastic filaments and pellets, liquids, slurries
What are four applications for material extrusion?
battery materials, ceramics, glasses, and composites
Which two stacking designs are used in DIW? Which distributes stress better?
Face centered tetragonal (distributes better), simple cubic.
What are alternative names for sheet lamination?
laminated object manufacturing, selective deposition lamination, ultrasonic additive manufacturing
What are three strengths to sheet lamination?
high volumetric build rates
low cost
combinations of metal foils and embedding components
What are typical materials for sheet lamination?
paper, plastic sheets, and metal foils/tapes
What is one negative to sheet lamination?
limited interest from academia
What are four lamination methods for sheet lamination?
adhesives, chemical, ultrasonic welding, brazing
What are four alternative names to vat photopolymerization?
stereolithography apparatus
digital light processing
scan, spin, and selectively photocure
continuous liquid interface production
What are three strengths of vat polymerization?
highest level of accuracy and complexity
smooth surface finish
accommodates large build areas
What materials are used for vat photopolymerization?
UV-curable photopolymer resins and piezo-electric materials.
What is projection microstereolithography?
3D printing technique based upon light and photochemistry
What is one disadvantage to material extrusion?
Nozzle gets clogged
What does the resolution depend on in material extrusion?
Nozzle diameter and pressure
For material extrusion, what method achieves the best precision?
Moving the platform rather than the nozzle
What is one disadvantage to vat photopolymerization?
Slow process
What is two photon polymerization
a sub-100nm resolution process from vat photopolymerization that uses photons from both sides on photon sensitive materials
Which AM technique has the highest spatial resolution during the build?
DED
What techniques are commonly used for metals and alloys?
PBF, DED, binder jetting, sheet lamination
What techniques are commonly used for polymers?
material jetting, vat photopolymerization
The resultant materials of laser and EB PBF differ in what ways?
grain size, phase, composition, residual stress, and dimension accuracy
3D printer
a machine used for 3D printing
CAM
computer-aided manufacturing - systems that use surface data to drive CNC machines
CNC
computer numerical control - computerized control of machines for manufacturing
IGES
initial graphics exchange specification - platform neutral data exchange, superseded by STEP
PDES
product data exchange specification
STEP
standard for exchange of product model data
STL
file format for 3D model data, originated from stereolithography. standard interface for AM systems
3D scanning
method of acquiring shape and size of an object as a 3D representation by recording xyz coordinates and converting to digital data
additive systems
machines used for AM
direct metal laser sintering
pbf process to make metal parts directly
facet
three or four sided polygon that represents an element of a 3D polygonal mesh surface or model. triangular facets used in STL files
fused deposition modeling
material extrusion process used to make thermoplastic parts through heated extrusion and deposition of materials layer by layer
laser sintering
pbf process that fuses particles at the surface layer by layer
prototype tooling
molds, dies, and other devices used to produce prototypes (bridge/soft tooling)
rapid prototyping
iterative AM of a design for form, fit, and functional testing
rapid tooling
use of AM to make tools or tooling quickly
reverse engineering
method of creating a digital representation to define shape, dimensions, and internal and external features
selective laser sintering
denotes the LS process from 3D systems corporation
sterolithography
a vat photopolymerization process used to produce parts from photopolymer materials in a liquid state
stereolithography apparatus
denotes SL machines from 3D systems corporation
subtractive manufacturing
making objects by removing material
surface model
mathematical representation of an object as a set of surfaces
tool/tooling
mold, die, or other device used in various manufacturing and fabricating processes
CAD
computer-aided design - use of computers for design of real/virtual objects
What two processes does EBM include?
PBF and DED
What is electron energy determined by?
acceleration voltage, beam size
What is the EBM material feed sources?
powder, wire, sheet
What are the properties of graphene aerogel?
large surface areas (700-1000 m^2/g)
lightweight (15 mg/cm^3)
electrically conductive (300 S/m)
ultra-compressible (up to 90% strain)
What is graphene aerogel used for?
DIW
