Test 1 Machining

Question 1

Types of Machining

Answer 1

Straight turning, cutting off, slab milling,

Question 2

CNC Machine

Answer 2

Computer Numerical Control, one machine does all the work. Run off of computer programs

Question 3

Forging

Answer 3

shaping of metal using pressure

Question 4

Tolerances

Answer 4

dimensions must lie within a certain range

Question 5

Cutting Ratio

Answer 5

r=To/Tc, depth of cut divided by chip thickness

Question 6

Rake Angle

Answer 6

tool face angle to vertical plane (alpha)

Question 7

Rake face

Answer 7

face touching chip

Question 8

shear angle

Answer 8

angle of shear plane to cutting direction

Question 9

Primary shear zone

Answer 9

where chips break off, place of the highest shear strain

Question 10

Secondary shear zones

Answer 10

second largest area of shear strain

Question 11

Chip Velocity

Answer 11

Vc= V(To/Tv)=Vr

Question 12

Power

Answer 12

V*Fc, need to know to determine power requirements to produce efficiently

Question 13

Power dissipated by

Answer 13

friction and heat, plastic deformation, 1.) shear along shear angle 2.) friction along chip/tool interface

Question 14

Areas of high heat

Answer 14

rake face- tool/chip interface

Question 15

Flank face

Answer 15

tool workpiece interface

Question 16

Rake face

Answer 16

too/chip interface

Question 17

Taylor Tool Life Equation

Answer 17

(VT)^N=C or (C/V)^(1/n)=T where T is time and V is cutting speed

Question 18

Heat

Answer 18

causes degregation, most heat goes into work piece but tool is smaller, faster speed, high temp

Question 19

Wear

Answer 19

Velocity*pressure/hardness; it is the result of relative motion times pressure

Question 20

Hardness

Answer 20

changes with temperatire

Question 21

Ways to save money on tool

Answer 21

mount expensive tool on cheap mount; coat inexpensive material with expensive material

Question 22

Coolant

Answer 22

removes heat, lubricates tool/work piece interface, and washes away chips

Question 23

Alternative Coolants

Answer 23

liquid nitrogen, mist cooling, dry lubrication

Question 24

Problems with coolants

Answer 24

expensive, have to dispose of safely

Question 25

Wear Limit

Answer 25

when tool is no longer useful;

Question 26

Effect of velocity on wear

Answer 26

increasing speed increases heating rate, which increases tool temperature, which increases wear

Question 27

Tool Wear Curves

Answer 27

Initially fast in break in zone, levels out, then rapidly increases in failure zone (no longer useable)

Question 28

Milling

Answer 28

workpiece is fed past a rotating cylindrial tool, with cutting edges perpendicular to the direction of the field

Question 29

machining advantages

Answer 29

it is very accurate and can cut within toleraces

Question 30

Tooling failure

Answer 30

gradual wear, fracture failure, temperature failuew

Question 31

Failure

Answer 31

occurs at rake face and flank

Question 32

Failure region

Answer 32

point at which wear begins to accelerate

Question 33

Important tool properties

Answer 33

toughness, hot hardness, wear resistance

Question 34

Maximize Production Rates

Answer 34

part handling time, machining time, tool change time

Question 35

Minimize cost

Answer 35

part handling, machining time, tool change cost, tooling cost

Question 36

Tool life Plots

Answer 36

use log-log plot to find C

Question 37

Machining Time

Answer 37

Tm=piDiameterlength/*feed rate/Velocity

Question 38

Velocity and time/cost

Answer 38

higher velocity, lower time, higher cost