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67 Cards in this Set
- Front
- Back
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3 categories of polymers
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elastomer, thermoset, thermoplastic
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3 examples of shaping
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casting, forging, machining
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example of a property enhancing process
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heat treatment
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2 examples of surface processing
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coatings and paints
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2 types of assembly
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Joining process and Mechanical assembly
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examples of joining
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welding, brazing, soldering
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examples of mechanical assembly
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screws, bolts, press fitting, rivits
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a high value of n means what
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that the metal can be strained further before necking
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definition of hardness
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resistance to permanent indentation
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hardness test methods for:
metals ceramics polymers |
Brinell and Rockwell
Vickers and Knoop durometer |
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forming metals while above the recrystalization temp
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hot working
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def. viscosity
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the resistance to flow for a given fluid
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more viscous means
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greater resistance to flow
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the reciprocal of viscosity, or ease at which a fluid flows
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fluidity
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For Newtonian fluids viscosity is
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constant
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1 centipoise =
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1 (mPas)
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thermoplastic is what type of fluid
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non-newtonian
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def. viscoelastic material
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viscoelastic materials exhibit properties of both elastic and viscous materials and have a time dependent strain. (creep)
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examples of viscoeleastic materials
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aluminum polymers wood
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3 classifications of RP machine
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liquid based
solid based powder based |
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RP machine that uses photopolymers and thermoplastics (liquid)
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SLA
FDM |
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RP machine that uses laminated sheets (solid)
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LOM
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RP machine that uses thermally bonded powders or selective binder
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SLS
3DP |
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The Objet is classified as
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a photo polymer inkjet printer
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the first RP method
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SLA
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why cant we us the base of the SLA machine to start the part
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the laser light is reflected and diffused off the base (bad resolution)
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the volume solidification rate for the SLA
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Q=Dtu
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SLA
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Stereolithography Apparatus
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FDM
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Fused Deposition Manufacturing
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LOM
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Laminated Object Manufacturing
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SLS
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Selective Laser Sintering
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3DP
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Three Dimensional Printing
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5 RP applications
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prototypes
assembly testing pattern for mold intricate internal geometries medical applications |
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3 problems with RP
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part accuracy
limited materials removal of support material |
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Def. Turning
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a single point cutting tool removes material from a rotating cylinder
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Def. Drilling
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A two edge cutting tool that rotates to create a hole
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Def. Milling
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a rotating cutting tool that is moved across a surface
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2 types of milling
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peripheral milling
end or face milling |
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3 types of machining
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milling
drilling turning |
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For roughing feeds and depths are:
cutting speeds are: |
large
slow |
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For finishing feeds ans depths are:
cutting speeds are: |
small
fast |
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in chip formation the temperature and pressure are highest where
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in the secondary shear zone
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in chip formation r is:
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chip thickness ratio
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Types of chip formation
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discontinuous
continuous continuous with built up edge serrated |
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high cutting temperatures cause:
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reduction in tool life
production of hot chips inaccuracies by way of thermal expansion |
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what percentage of energy is converted to heat in the cutting process
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98%
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def. chamfer in terms of the turning method
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an angel is cut into the corner of the cylider
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def. cutoff in terms of the turning method
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too is fed radially inward until it reaches the center of the part and the part is cut off
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def. facing in terms on the turning method
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the tool is always fed radially INWARD to smooth the end face of the cylinder
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def. threading in terms of the turning method
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a pointed tool is fed at a large feed rate creating threads
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def. contour turning in terms of the turning method
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a tool follows a contour other than straight
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which direction does an engine lathe turn
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CCW
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boring compared to drilling
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boring can only enlarge an existing hole
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difference between reaming and tapping
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reaming enlarges the hole
tapping cuts threads in a hole |
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advantages to reaming
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better diameter tolerance
improves surface finish |
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list types of milling and function
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face
end profile slab slotting |
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a mill turn center can perform what types of machining operations
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turning, milling, drilling
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def. broaching
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multiple tooth cutting tool slides past the work piece and has progressively larger teeth to cut key slots and unique shapes.
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Three modes of tool failure, which is preferred.
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Fracture failure
Temperature failure Gradual wear |
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2 types of wear on the cutting tool along with their locations
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Crater wear, rake face
Flank wear, side of tool |
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what is the effect of cutting speed on tool wear
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the higher the cutting speed the faster the tool wears which means a shorter tool life
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3 desired tool properties
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Toughness (avoid fracture failure)
Hot hardness (retain hardness at high temps) wear resistance (hardness to resist abrasive wear |
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for Hot hardness, if temperature increases then hardness:
what is the best material for tool surfaces i.e. highest hot hardness |
decreases
ceramics |
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list 4 machining processes that use single point tools
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turning
boring shaping planing |
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list 6 machining processes that use multiple cutting edges
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drilling
milling broaching sawing reaming tapping |
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list 3 functions of cutting fluids
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improve chip removal
reduce friction improve surface finish |
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name types of fluids and their corresponding cutting speeds
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water based coolant, high speeds
oil based lubricant, low speeds |
