ACTUAL Questions And CORRECT
Answers
Additive Manufacturing - CORRECT ANSWER - process of creating a physical object
through selective fusion, sintering or polymerization of materials; common to all processes is
that the parts are made by adding layers; very little waste
Subtractive Processes - CORRECT ANSWER - (machining) excess material is removed
what does layer thickness depend on ? - CORRECT ANSWER - how close the part
produced is to the computer model
other names for AM - CORRECT ANSWER - rapid prototyping; freeform fabrication ;
direct digital manufacturing
benefits of AM - CORRECT ANSWER - geometric shapes that could not be built any
other way; no need for process planning (all parts are built with same simple steps); rapid
fabrication of parts and complex components
fabrication of parts with customized properties - CORRECT ANSWER - (1) parts that are
rigid in one direction and compliant in another (2) parts with non-uniform density (3) multi-
material components (4) parts with non-homogenous material composition
Difference between AM and CNC
(Materials) - CORRECT ANSWER - CNC:
homogenous materials
mostly brittle metals and alloys
can work with softer materials
AM: many anisotropic materials
, polymer
waxes
metals composites ceramics
Difference between AM and CNC (speed) - CORRECT ANSWER - CNC:
can remove materials quickly
needs lengthy setups and process planning
multi-stage process
finishing may take days or weeks
AM:
Likely to take hours
can be single stage process
finishing may take hours or days
Difference between AM and CNC (complexity) - CORRECT ANSWER - CNC: bc
spindle principle, complex features may require the tool to travel to locations that are impossible
needs to break complex parts into components to be later assembled
AM: high capabilities as complexity increases; not hampered by undercuts and internal features
Difference between AM and CNC(Accuracy) - CORRECT ANSWER - CNC: determined
by the positioning mechanisms for the three orthogonal axes
servo or stepper motors
AM: many machines operate within micrometer level resolution
different resolutions for each axis (vertical vs lateral)
vertical build axis determines the layer thickness and is of lower resolution
determine minimum feature size
Difference between AM and CNC (geometry and programming) - CORRECT ANSWER -
CNC: surfaces must be generated in 3d space