Brainscape's Knowledge GenomeTM

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


See full index

Additive Manufacturing > Other polymer and non-metal processes > Flashcards

Other polymer and non-metal processes Flashcards

1
Q

What are the categories of the “other” polymer and non metal AM processeS?

A
  1. Extrusion based systems
  2. Jetting methods
  3. Lamination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the history of Extrusion-based systems?

A
  1. Invented by Scott and Lisa Crump in 1988
  2. First U.S. patent was issued in 1992
  3. FDM commercialised through Stratasys Inc. in 1992
  4. Continues to be main supplier of industrial FDM systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the working principle of the extrusion based systems?

A

Molten plastic extruded through a nozzle to create cross-section.

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

Describe the step by step process of the extrusion based system

A
  1. Plastic filament supplied to heated extrusion nozzle
  2. Plastic melts & is extruded in appropriate cross- section
  3. Chamber heated to just below Tm of the plastic
  4. Support structures for overhanging geometries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the typical post processing procedures taking place on the extrusion based system products?

A
  1. Remove support material
    • Breakaway supports – manual removal
    • Soluble supports – dissolve in ‘water-based’ solution
    • May need to apply temperature, agitation etc.
    • Can be best to manually remove majority of supports first
  2. Varying choice of support structures (experience is key)
  3. Smoothing/finishing
    (finishing touch smoothing station with semi automated capacity to smoothen parts can be used!) - Solvent-based process – claims to reduced surface roughness to one-tenth, with no reduction in accuracy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the advantages of the extrusion based system?

A
  1. Office friendly – no hazardous materials (but can be loud/hot!)
    • Some companies (e.g. Materialise) make use of this for heating their facility!
  2. Several available materials, some of which compare with traditional materials
  3. Coloured materials (generally only one at a time)
  4. Range of systems available (size, speed, cost etc.)
  5. Soluble supports
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the limitations of the extrusion based system?

A
  1. Slow production of parts with large cross-sections
  2. Poor Mechanical properties, particularly in z direction
  3. Surface finish can be poor
  4. Support structures not always as easy to remove as you might think…
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What has stratasys dramatically improved over the last 10 years?

A

Ten years ago, Stratasys were not renowned for the quality of their parts…

But they’ve made major advances in surface finish (As-produced and with finishing) and in mechanical properties (Especially in the z-direction)

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

Examples of other extrusion based systems?

A
  1. Envisiontec 3-D Bio-plotter (Designed specifically for processing of bio-materials for Computer-Aided Tissue Engineering)
  2. Hewlett-Packard Designjet 3D systems (Basically a re-branding of small Stsratasys systems)
    ONLY LASTED 2 YEARS AND IT WAS PULLED FROM MARKET (think why?)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are examples of personal systems available in the market for extrusion based processes?

A

Defined as costing

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

What are the characteristics of Fab@hoME?

A
  • Fab@Home – the first example!
  • (58 out of 66 units in 2007)
  • 3D printers to make at home
  • Low cost, syringe-based system, almost any material can be processed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the applications of extrusion based systems?

A
  1. Tooling (assembly tools)
  2. Carbon Fiber layup
  3. Vacuum casting
  4. Measurement and Inspection (rapid fit for packaging)
  5. Space applications (weight restrictions in space means we cannot carry a lot of parts; easier to make them there!)
  6. Education: Schools, Museums (low cost method of introducing people to tech)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the difference between printing and jetting?

A
  1. Printing: Print secondary material onto base powder (e.g. binder)

VS

  1. Jetting: Deposit build (and support) material directly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two major categories of RP jetting technologies?

A
  1. Thermal phase change

2. Photopolymer phase change

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

What happens in the thermal phase change systems in jetting?

A

Thermal phase change

  • Materials deposited in liquid/molten form
  • Harden once deposited as they rapidly cool
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens in the photopolymer phase change systems in jetting?

A

photopolymer phase change

  • Material is deposited
  • Curing (e.g. UV) of the layer solidifies the part
17
Q

What process is similar in a way to thermal phase changes?

A

Very similar to the Objet process, except the material hardens when cooled, rather than being UV-cured

Supports may be separate material, or weaker structure of build material

18
Q

What is the main material used in jetting applications (thermal phase)?

A

mainly wax or acrylic-based materials

19
Q

What are some example applications for thermal jetting systems produced by 3D Systems?

A

Example applications include:

  • Wax patterns for foundry casting or jewellery
  • Hearing aids/other small, personalised medical parts
  • Architecture
20
Q

What are the characteristics of the Solidscape themal jetting system?

A

Solidscape (now owned by Stratasys…)
• Separate inkjet print-heads for build and support material
• Build and support material jetted onto substrate
• Cutter mills entire layer to ensure layer thickness consistency and flatness
• Particle collector removes unwanted ‘debris

21
Q

What is solidscape best suited for?

A

Solidscape
• Aimed particularly at production of ‘wax-like’ patterns for casting of small, intricate features, e.g.:
• Dental applications
• Jewellery… Think back to previous lectures – why is this such a big area of interest?

22
Q

What is the working principle of lamination/laminating processes?

A

Profiles of cross-sections cut from sheet material, then stacked or bonded (remember Laminate Tooling)

Laminated: formed or manufactured in a succession of layers of material

Examples
• Plywood (since early Egyptians!)
• Document protection
• Transformer cores – minimise eddy current losses 
• Topological maps
• Windshields
23
Q

Examples of laminated products?

A
  • Plywood (since early Egyptians!)
  • Document protection
  • Transformer cores – minimise eddy current losses
  • Topological maps
  • Windshields
24
Q

What is arguably the simplest AM process?

A

Lamination

25
Q

What is the material range for Laminate Manufacture?

A

Any material which is available in sheet or plate form

26
Q

Are there proprietary Laminate AM Manufacture Systems?

A

No single Laminate Manufacture AM system

TECHNIQUE CAN’T BE PATENTED!

27
Q

Which process accounts for the most commercial application of Laminate AM Manufacture?

A

Laminated Object Manufacturing

28
Q

What are the features of Laminated Object Manufacturing?

A
  1. Paper-based process
  2. Cross-sections of sheets of paper cut using laser or knife
  3. Paper sheets bonded in successive layers
  4. Areas to be removed after build are cross-hatched to allow removal
  5. High levels of complexity CAN be achieved, but finishing time must be considered
29
Q

What are the post processing requirements of Laminated Object Manufacturing?

A
  1. Block (including part and supports) is detached from platform (e.g. fixed on with double-sided tape)
  2. Support areas broken away to reveal the part • This normally requires a chisel, patience, and time!
  3. Parts sealed to prevent ingress of moisture
  4. Parts can be sanded, polished or painted
  5. High levels of complexity CAN be achieved, but finishing time must be considered
  6. High possibility of damaging complex parts
30
Q

What are the benefits of Laminated Object Manufacturing?

A
  1. Relatively simple set-up and operation
  2. Low material cost
  3. Scalable process for large parts
  4. Multiple parts can be nested
    • (self-supporting process)
  5. Build can be paused at any point, without creating additional weaknesses
  6. Relatively fast (laser system) – only cutting profile of cross-sections: Compare with e.g. Laser Sintering and Stereolithography, where the entire cross-section must be scanned!
31
Q

What are the limitations of Laminated Object Manufacturing?

A
  1. Removal of support blocks from small features can lead to part damage
  2. Sealing required to prevent moisture ingress – distortion of parts can occur
  3. Difficult to produce enclosed volumes, due to support removal
  4. Not for functional testing
  5. Laser can cause charring of parts, and can also be a fire hazard
32
Q

What are the applications of Laminated Object Manufacturing?

A

Parts have similar appearance and ‘workability’ to wood

Popular for production of patterns for sand castings (traditionally use wood) –> Compact sand around pattern, remove pattern to leave cavity into which molten metal is poured

Mainly used for tooling or visualisation!

33
Q

What are examples of systems for laminated object manufacture?

A
  1. Mcor Technologies (knife based system)
  2. Staples myeasy3D (online system for production of parts)
  3. Solido (no longer sold); Similiar process, but with rigid PVC-based plastic film; Layers are bonded using a solvent (knife based)
  4. CAL-LEM Process (ceramic or metal materials in tape form -> outline of layer is laser cut -> required sections removed from sheet and are bonded -> ceramic material contains polymer binders -> thermal treatment removes these binders and sinters ceramic)
34
Q

What are some processes based

A
  1. Coated foundry sand – similar to standard materials
    - Excellent method for producing one-off castings
    - Developed to help BMW make engine blocks

Additive Manufacturing (9 decks)

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