MMET 281 FINAL EXAM QUESTIONS
WITH 100% CORRECT ANSWERS
What are the materials processed with the laser engineered net shaping (LENS)
method? - Answer- 316 and 304L Stainless Steels
Nickel alloys
Tool Steels
Titanium
Limited amounts of aluminum, tungsten, etc.
List some mechanical properties of a part produced by the laser engineered net shaping
process (LENS). - Answer- Ultimate Tensile Strength: 115 KSI
Yield Tensile Strength: 85 KSI
Total Elongation in 1 in: 30%
True or False: In laser engineered net shaping (LENS), a faster cooling rate gives
smaller grain size and provides higher strength. - Answer- True
True or False: The strength of laser engineered net shaping (LENS) parts is enhanced
at the expense of ductility. - Answer- False
(Increase in strength without ductility being affected)
True or False: For laser engineered net shaping (LENS) manufactured parts, achieving
a 90° overhang is another driver for process improvement. - Answer- True
Summary of LENS: - Answer- Category: directed energy deposition
Feedstock: powder
Layer creation: powder blowing
Layer patterning: selective movement of blowing nozzle and energy source
Direct or indirect: direct
Support needed: yes
Pros: functionally gradient materials, large build envelope, good for repair
Cons: expensive equipment and materials, poor surface finish
Summarize the other processes used for directed energy deposition additive
manufacturing. - Answer- Wire arc additive manufacturing: lower accuracy but higher
deposition rate
Electron beam additive manufacturing: lower accuracy but higher deposition rate
Hybrid (additive + subtractive) manufacturing: material deposition + CNC machining
Name some examples of subtractive shaping. - Answer- Machining
,Grinding
Drilling
Define subtractive shaping. - Answer- Shaping a material by subtracting excess material
from the original material
Name some examples of formative shaping. - Answer- Forging
Pressing
Bending
Casting
Define formative shaping. - Answer- Shaping a material by deforming or reflowing the
original material
Define additive shaping. - Answer- Shaping a material by the successive addition of
material
Define 3D Printing. - Answer- An additive manufacturing process based on a traditional
printing operation, such as binder jetting or material jetting
(Recent media exposure have led to this term becoming a general term for the entire
field of additive manufacturing)
What is the additive manufacturing sequence? - Answer- Begin with CAD model
Generate a .STL model
Support Generation
Slice the model (layer thickness)
Final build file (tool path)
Print
Post processing
Describe the early applications of additive manufacturing from the 1980s to the 2000s. -
Answer- In the late 1980s to early 1990s, it was mostly used for rapid prototyping
In the 1990s and early 2000s, it became popular for producing tooling
In the late 1990s to mid 2000s, it has become all-round rapid manufacturing, capable of
producing end-use parts
Name some of the early examples of products made through additive manufacturing. -
Answer- Cranial and orthodontic implants
Tools for assembly such as jigs and fixtures
Molds and inserts
Turbomachinery applications such as turbine blades, bearings, etc.
Why is additive manufacturing considered "an enabling technology?" - Answer-
Whereas conventional manufacturing methods have a sharp increase in cost when part
complexity rises, additive manufacturing can maintain low costs regardless of the
design's complexity
, List the main advantages of additive manufacturing. - Answer- Minimized material
consumption
Individual variation at very little additional cost
Reduced number of components
Reduced number of operations
Automatic process planning based on CAD model
Generic fabrication machine (does not require part-specific fixture/tooling)
Minimal human operation
How is supply chain impacted by additive manufacturing? - Answer- There are simpler
forms of raw materials
There are less manufacturing operations
Less assembly is required
Briefly give examples of the DHL perspective and its use of additive manufacturing. -
Answer- -Ability for consumers to get spare parts on demand (i.e. car repair shop
getting item printed instantly)
-Individualized direct parts manufacturing (prosthetics, etc.)
-End of runway services (printed, packed, ready to fly to destination)
-3D print shops (users upload what they want printed and pick up/USB drive on
location)
-3D printing on the go! (printing in delivery trucks as products are being shipped)
What are the challenges of additive manufacturing? - Answer- It is hard to standardize
everything because there are so many technologies, machine systems, etc.
Why is standardization needed in additive manufacturing? - Answer- Traceability and
quality management purposes
What are the material types that can be used for additive manufacturing? - Answer-
Polymers, ceramics, metals, composites, etc.
What are the material forms that can be used for additive manufacturing? - Answer-
Filaments, resins, powders, sheets, etc.
What are the processes that are used for additive manufacturing? - Answer- A wide
range of systems with different approaches, materials, capabilities, and purposes
What are the seven standard process categories defined by the ASTM Committee F42?
- Answer- Material Extrusion
Vat Photopolymerization
Material Jetting
Binder Jetting
Sheet Lamination
Powder Bed Fusion
WITH 100% CORRECT ANSWERS
What are the materials processed with the laser engineered net shaping (LENS)
method? - Answer- 316 and 304L Stainless Steels
Nickel alloys
Tool Steels
Titanium
Limited amounts of aluminum, tungsten, etc.
List some mechanical properties of a part produced by the laser engineered net shaping
process (LENS). - Answer- Ultimate Tensile Strength: 115 KSI
Yield Tensile Strength: 85 KSI
Total Elongation in 1 in: 30%
True or False: In laser engineered net shaping (LENS), a faster cooling rate gives
smaller grain size and provides higher strength. - Answer- True
True or False: The strength of laser engineered net shaping (LENS) parts is enhanced
at the expense of ductility. - Answer- False
(Increase in strength without ductility being affected)
True or False: For laser engineered net shaping (LENS) manufactured parts, achieving
a 90° overhang is another driver for process improvement. - Answer- True
Summary of LENS: - Answer- Category: directed energy deposition
Feedstock: powder
Layer creation: powder blowing
Layer patterning: selective movement of blowing nozzle and energy source
Direct or indirect: direct
Support needed: yes
Pros: functionally gradient materials, large build envelope, good for repair
Cons: expensive equipment and materials, poor surface finish
Summarize the other processes used for directed energy deposition additive
manufacturing. - Answer- Wire arc additive manufacturing: lower accuracy but higher
deposition rate
Electron beam additive manufacturing: lower accuracy but higher deposition rate
Hybrid (additive + subtractive) manufacturing: material deposition + CNC machining
Name some examples of subtractive shaping. - Answer- Machining
,Grinding
Drilling
Define subtractive shaping. - Answer- Shaping a material by subtracting excess material
from the original material
Name some examples of formative shaping. - Answer- Forging
Pressing
Bending
Casting
Define formative shaping. - Answer- Shaping a material by deforming or reflowing the
original material
Define additive shaping. - Answer- Shaping a material by the successive addition of
material
Define 3D Printing. - Answer- An additive manufacturing process based on a traditional
printing operation, such as binder jetting or material jetting
(Recent media exposure have led to this term becoming a general term for the entire
field of additive manufacturing)
What is the additive manufacturing sequence? - Answer- Begin with CAD model
Generate a .STL model
Support Generation
Slice the model (layer thickness)
Final build file (tool path)
Post processing
Describe the early applications of additive manufacturing from the 1980s to the 2000s. -
Answer- In the late 1980s to early 1990s, it was mostly used for rapid prototyping
In the 1990s and early 2000s, it became popular for producing tooling
In the late 1990s to mid 2000s, it has become all-round rapid manufacturing, capable of
producing end-use parts
Name some of the early examples of products made through additive manufacturing. -
Answer- Cranial and orthodontic implants
Tools for assembly such as jigs and fixtures
Molds and inserts
Turbomachinery applications such as turbine blades, bearings, etc.
Why is additive manufacturing considered "an enabling technology?" - Answer-
Whereas conventional manufacturing methods have a sharp increase in cost when part
complexity rises, additive manufacturing can maintain low costs regardless of the
design's complexity
, List the main advantages of additive manufacturing. - Answer- Minimized material
consumption
Individual variation at very little additional cost
Reduced number of components
Reduced number of operations
Automatic process planning based on CAD model
Generic fabrication machine (does not require part-specific fixture/tooling)
Minimal human operation
How is supply chain impacted by additive manufacturing? - Answer- There are simpler
forms of raw materials
There are less manufacturing operations
Less assembly is required
Briefly give examples of the DHL perspective and its use of additive manufacturing. -
Answer- -Ability for consumers to get spare parts on demand (i.e. car repair shop
getting item printed instantly)
-Individualized direct parts manufacturing (prosthetics, etc.)
-End of runway services (printed, packed, ready to fly to destination)
-3D print shops (users upload what they want printed and pick up/USB drive on
location)
-3D printing on the go! (printing in delivery trucks as products are being shipped)
What are the challenges of additive manufacturing? - Answer- It is hard to standardize
everything because there are so many technologies, machine systems, etc.
Why is standardization needed in additive manufacturing? - Answer- Traceability and
quality management purposes
What are the material types that can be used for additive manufacturing? - Answer-
Polymers, ceramics, metals, composites, etc.
What are the material forms that can be used for additive manufacturing? - Answer-
Filaments, resins, powders, sheets, etc.
What are the processes that are used for additive manufacturing? - Answer- A wide
range of systems with different approaches, materials, capabilities, and purposes
What are the seven standard process categories defined by the ASTM Committee F42?
- Answer- Material Extrusion
Vat Photopolymerization
Material Jetting
Binder Jetting
Sheet Lamination
Powder Bed Fusion
