Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MPR095 > Additiv manufacturing > Flashcards

Additiv manufacturing Flashcards

1
Q

Manufacturing

A

The creation or production of goods
or
Turning raw materials and components into products
* Subtractive
* Formative
* Casting
* Additive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Subtractive

A
  • Subtractive manufacturing is a term for various controlled machining and material removal
    processes
  • that start with solid blocks, bars, rods of plastic, metal, or other materials
  • that are shaped by removing material
  • through cutting, boring, drilling, grinding or milling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Additive Manufacturing?

A
  • Additive Manufacturing is a method in which the part is created by a layer- additive process.
  • Objects are created based on digital 3D models designed using Computer-Aided Design (CAD)
    software
  • Using a specialized software, a 3D CAD model is cut into very thin layers or cross-sections.
  • The AM machine constructs the part layer by layer until a solid duplication of the CAD model is
    generated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The use of AM technology is
developing in many industries:

A
  • Medical
  • Aerospace
  • Automotive and transportation
  • Consumer goods
  • And many more
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the global market of AM
growing so fast ?

A
  • Increased design freedom
  • Light weight structures
  • New functions such as complex internal channels or several parts built in one.
  • Net shape process meaning less raw material consumption
  • Almost no tools needed
  • Short production cycle time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

7 Families of AM techniques
as per International Organization for Standardization (ISO)

A

Material Extrusion: Material is extruded through a nozzle (e.g., FDM, FFF).
Vat Photopolymerization: Liquid resin is cured by light (e.g., SLA, DLP).
Powder Bed Fusion (PBF): Powder is fused with lasers or electron beams (e.g., SLS, SLM, EBM).
Material Jetting: Droplets of material are deposited (e.g., PolyJet).
Binder Jetting: A liquid binder joins powder particles (e.g., Metal Binder Jetting).
Sheet Lamination: Layers of material are bonded together (e.g., LOM).
Directed Energy Deposition (DED): Material is melted and deposited simultaneously (e.g., LENS, EBAM).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

AM techniques metal

A

PBF, DED, MEX, BJT, MJT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Powder Bed Fusion-Metal

A

By means of a movable laser beam, metal
powder is selectively melted locally layer by
layer, thus solidifying a cross-section of the
component.
Selective Laser Melting (SLM)
Or
Laser powder bed fusion (LPBF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Powder Bed Fusion-Metal

A

By means of a movable electron beam,
metal powder is selectively melted locally
layer by layer, thus solidifying a cross-
section of the component.
Electron Beam Melting (EBM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Direct Energy Deposition (DED)

A

Material is applied and melted
simultaneously by a laser beam.
The following solidification of the melt
generates new layers which are
arranged above and next to each
other.
Laser Engineering Net Shape (LENS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Direct energy deposition (DED)

A

Material powder is applied in layers
with very high kinetic energy.
Components close to the final contour
are produced. Material combinations
are possible.
Metal Powder Application (MPA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Direct Energy Deposition (DED)

A

Metal wire is melted by arc welding
and applied locally in layers to quickly
produce large near-net-shape metal
structures.
Wire and Arc Additive Manufacturing
(WAAM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Material Extrusion

A

Wire-shaped metal-containing plastic, so-called
filament, is plasticized in a nozzle unit and
selectively dosed locally layer by layer.
Fused Deposition Modeling (FDM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Binder Jetting

A

Tiny binder droplets are selectively applied locally
through many nozzels and in layers onto metal
powder. They stick the powder material together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Material Jetting

A

A metal particle solvent fluid is selectively dosed
locally by a nozzle unit. The solvent evaporates and
the nanoparticles bond together.
Nano Particle Jetting (NPJ)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Major metal AM techniques

A
  • Laser powder bed fusion (LPBF)
  • Electron beam melting (EBM)
  • Binder Jetting
  • Direct energy deposition (DED)
17
Q

Laser powder bed fusion (LPBF) -Metal

A
  • A powder layer is first applied on a building
    platform with a re-coater (blade, roller or scraper)
  • A laser beam selectively melts the layer of powder
  • Then the platform is lowered, and a new powder
    layer is applied
  • The laser beam melting operation is repeated
  • After a few thousand cycles (depending on height
    of the part), the built part is removed from the
    powder bed
18
Q

Laser powder bed fusion (LPBF) -Metal

A

Important parameters
* Laser power
* Laser beam diameter
* Layer thickness
* Scan velocity
* Hatch distance
* Scan strategy
* Powder material (particle size, shape)
* Etc…

19
Q

Process parameters optimization

A
  • Defects
  • Microstructure
  • Mechanical properties
  • Functional properties
20
Q

Process parameters optimization

A

Microstructures of as-built LPBF
tungsten when employing three
different scanning strategies
Top Front
Chessboard
Zigzag
Remelting

21
Q

Process parameters optimization

A

Energy density

Volume energy density
𝐸 = 𝑃/ 𝑣.ℎ.𝑡
Areal energy density
𝐸 = 𝑃/𝑣.ℎ
Linear energy density
𝐸 = 𝑃/𝑣

22
Q

Post processing operations

A
  • Machining
  • EDM
  • Peening
  • Grinding
  • Polishing
  • Surface treatment
  • Heat treatment
  • Hot isostatic pressing (HIP) to eliminate
    residual porosities
23
Q

Electron Beam Melting

A

The EBM rocess (Courtesy of Arcam)
➢ A high-power electron beam that generates the energy needed
for high melting capacity and high productivity.
➢ The electron beam is managed by electromagnetic coils
providing extremely fast and accurate beam control.
➢ The EBM process takes place in vacuum ( ≥ 1×10-5 mbar)
➢ For each layer in the build the electron beam heats the entire
powder bed to an optimal ambient temperature, specific for the
material used.
➢ As a result, the parts produced with the EBM process are
almost free from residual stresses

24
Q

Electron Beam Melting

A
  • Electrons as energy carriers - provides deep penetration and low reflection in the powder.
    Electron Beam Melting
  • The electron’s ability to reach far into the material and
    homogenously melt the powder particles.
  • This facilitates melting of highly reflective metals without the risk
    of vaporizing the surface of the particle before melting the core
25
Q

Electron Beam Melting

A
  • Unique characteristic of EBM is the ability to keep the
    entire build at an elevated temperature ~1,000 °C
  • This ensures a correct microstructure and parts free from
    residual stresses
  • Post heating can be avoid- low cos
  • Hot process - provides low internal stress which enables production of crack prone materials, bulky parts
    or thin, free-floating beams to be produced.
26
Q

Electron Beam Melting

A
  • The vacuum system provides a base pressure of 5 x10-5 mbar
  • The very low oxygen level in the build chamber allows processing of
    reactive material and eliminates the need for a laminar flow of inert gas
  • The vacuum process ensures excellent susceptibility to Hot Isostatic
    Pressing (HIP), eliminating pores in the material
  • This means if pores are created in the EBM process, the pores contains
    a vacuum. Vacuum pores are easily removed by HIP compared to gas-
    filled pores.
  • Vacuum process - enables extreme cleanliness
27
Q

Electron Beam Melting

A
  • The metal powder around the build part is sintered
  • This means the metal powder particles are heated and slightly
    attached to each other, without reaching the melt temperature
  • This provides a stable environment for the part being built.
  • The sintered powder acts as a support structure for the part being
    built. In most cases, no additional mechanical support structures are
    needed
  • Parts produced free floating in sintered powder – allows tight stacking of parts for high productivity
    and the possibility to build with no or limited support.
28
Q

Metal Binder Jetting

A
  • An AM process in which a liquid bonding agent is selectively deposited
    to join powder particles;
  • Layer of powder is spread by an automated roller and print heads apply
    a liquid binder and color simultaneously to create a cross section of the
    built component object on the powder layer (the same principle as an
    inkjet paper printer but powder is the medium instead of the paper)
  • Binder jetting of metals → multi-step process
29
Q

Metal Binder Jetting

A
  • Multi-step process: forming, drying, debinding, sintering
  • Suited for mass production,
  • Many parts printed on build plate, multiple nozzles >25000
  • Forming/jetting – sets the shape from the CAD
  • Debinding – removes the organic binder (separate step or included in intering step)
  • Sintering* – heating at 80% of melt temperature in controlled atmosphere,
  • shrinkage from 55-60% relative density (after debinding) to >95% relative density
    *important to control shrinkage in all directions to keep shape and avoid distortion
30
Q

Metal Binder Jetting

A
  • Non-structural and structural
    metallic parts;
  • Art and jewellery
  • Medical prototypes;
  • Reverse engineering
    Applications
31
Q

Metal Binder Jetting

A

Advantages Disadvantages
Low cost Poorer accuracy
Low energy consumption Require sintering/infiltration
High speed – up to 200 cm3/min of
printed components
Small parts in case of metals
Higher productivity than other powder
metalAM
Complex fine cooling channels not
possible

32
Q

Direct energy deposition (or laser
metal deposition)

A
  • Laser Engineered Net Shaping (LENS)
  • Laser Deposition Technology (LDT)
  • Directed Light Fabrication (LDF)
  • Direct Metal Deposition (DMD)
  • 3D Laser Cladding
  • Laser Generation
  • Laser-Based Metal Deposition (LBMD)
  • Laser Freeform Fabrication (LFF)
  • Laser Direct Casting
  • Laser Cast
  • Laser Consolidation
33
Q

Benefits of Direct Energy Deposition
process

A

➢ Repair of parts that up to now were impossible
➢ No dimensional limits (apart from the machine size)
➢Control of the material deposited (gradients, multimaterials, monolithic …)
➢Eco innovative process: less material loss, no tool process

34
Q

Direct energy deposition

A

➢ Start with 3D CAD/.stl file.
➢ Laser creates molten pool on substrate surface.
➢ Powder is injected into molten pool
➢ Parts built line by line and layer by layer

35
Q

Direct energy deposition

A

Benefits:
* capability for advanced control of microstructure, unique microstructures
* capability of producing directionally solidified and single crystal structures
* application for repairing and refurbishing defective and service damaged high technology components
(e.g. turbine blades)
* addition of features
* capability of producing in-situ generated composite and heterogeneous material parts
* deposition of thin layers of dense, corrosion resistant and wear resistant materials to improve
performance and lifetime of the components;
Limitations:
* poor resolution (accuracy ≤0.25 mm)
* surface finish (surface roughness ≥25 μm)
* limited freedom in design - lattice structures and narrow internal channels are not possible
* anisotropy –properties different in X-Y and Z-direction.

36
Q

Metal powder for additive manufacturing
The quality of metal powder have a major influence on properties, but it can also influence:

A

✓The build-to-build consistency
✓The reproducibility between AM machines
✓The production of defect-free components
✓The manufacturing defects on surfaces

37
Q

Powder manufacturing processes

A

Gas atomisation is the most common process for AM
because it ensures:
* Spherical powder shape
* Good powder density, thanks to the spherical shape
and particle size distribution
* Good reproducibility of particle size distribution

38
Q

Other powder manufacturing process

A

❖Water atomizing
* Flake-like shape
* High oxygen content
❖Oil atomizing
* Flake-like shape
* High oxygen content
❖Plasma atomizing
* Low oxygen content
❖ Milling
* Coarse, angular powder
* High oxygen content

39
Q
A

MPR095 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions