Chapter 21

Question 1

Machining

Answer 1

The process of removing unwanted material in the form of chips

Question 2

Metal cutting or metal removal

Answer 2

Removing unwanted pieces of metal through machining in the form of chips.

Question 3

Seven chip formations

Answer 3

Turning, milling, drilling, sawing, broaching, grinding (abrasive machining), and shaping (planing).

Question 4

Speed

Answer 4

Velocity of cutting tool relative to the workpiece

Question 5

Feed

Answer 5

Is the amount of material removed per revolution.

Question 6

Depth of cut

Answer 6

Distances the tool is plunged into the surface.

Question 7

Metal removal rate

Answer 7

Amount of material removed per pass

Question 8

Shop equations

Answer 8

Basic equations for lathe operations.

Question 9

Boring

Answer 9

Produces a larger hold to meet a precision after drilling.

Question 10

Milling

Answer 10

Milling, slab milling, and face milling are multiple tooth processes.

Question 11

Orthogonal machining

Answer 11

Carried out for research processes. They simplify tool geometry down from three dimensions to two. This allows them to cut metals and test mechanis and theory and develop values for specific power and energy.

Question 12

Orthogonal plate machining

Answer 12

Machining a plate, low speed, in a milling machine.

Question 13

Orthogonal tube turning

Answer 13

End cutting a tube wall in a turning set up

Question 14

Orthogonal disk machining

Answer 14

End cutting a plate with tool feeding in a face direction. High speed.

Question 15

Oblique machining

Answer 15

Milling drilling and single point turning. Cutting edge and motion are not perpendicular to one another.

Question 16

Back take angle

Answer 16

The angle that the tool makes with respect to a vertical from the workpiece.

Question 17

Shearing

Answer 17

Chip is formed by shearing

Question 18

Orthogonal tube turning does

Answer 18

Solid cylinders that have had a groove machined in the end to form a tube wall

Question 19

Plastic deformation

Answer 19

Occurs at the radial compression zone that travels ahead of the tool as it passes the workpiece

Question 20

Shear angle

Answer 20

Angle as the tool passes the workpiece to make a chip.

Question 21

Free machining steels

Answer 21

Have small percentages of hard second phase particles

Question 22

Chatter/Vibration

Answer 22

The mechanism by which a process disssipates energy

Question 23

Chatter

Answer 23

A self excited vibration that is caused by closed force displacement

Question 24

Chatter can be caused by?

Answer 24

Changes in velocity, friction, build up, workpiece variation. More energy is inputted than can be dissipated.

Question 25

Free Vibration

Answer 25

Response to any initial condition or sudden change. The amplitude decreases with time. Interrupted marching is an example.

Question 26

Forced vibration

Answer 26

Response to a periodic input, repeating with time. The amplitude remains constants as it in periodically inputted. Unbalance, misalignment, tooth impacte are examples

Question 27

Self excited vibration

Answer 27

Periodic response to a constant input. Vibration may grow in amplitude. Surface waviness is an example

Question 28

How do you recognize chatter?

Answer 28

Screech, buzz, whine. Results in an unacceptable surface finish. There are visible surface undulations

Question 29

Important factors that influence stability?

Answer 29

Cutting stiffness, cutting process parameters (speed, feed, DOC, total width), cutter geometry, dynamic characteristic (fixture, workpiece)

Question 30

Matching operations

Answer 30

Require an overlap of cutting paths

Question 31

Regenerative chatter

Answer 31

A constant chip thickness results in a steady cutting force and eliminates feedback mechanism.

Question 32

Factors that influence chatter?

Answer 32

Cutting stiffness: property related to hardness and work hardening, the machinability of materials. Larger cutting forces may be needed and greater displacement happens.

Question 33

Factors of chatter?

Answer 33

Speed: speed affects the phase shift between overlapping surfaces regeneration of vibration.

Question 34

Process damping

Answer 34

Interference and friction dissipates energy in the form of heat

Question 35

Influences of chatter?

Answer 35

Feed; feed controls the severity of the vibration.

Question 36

Factors of chatter?

Answer 36

DOC: primary cause and control of chatter.

Question 37

Factors of chatter:

Answer 37

Total width of chip: Influences the stability of the process.

Question 38

Cutting tool geometry

Answer 38

Influences the magnitude and direction of the cutting force.

Question 39

Factors of chatter:

Answer 39

A positive back rake angle directs the cutting force to be more tangential, and increases stability

Question 40

Factors of chatter

Answer 40

Reduced clearance angle: increases friction contact, dissipates heat, and stabilized chatter.

Question 41

Factors of chatter:

Answer 41

Size, shape, and lead angle of insert: a reduced lead angle and a mess round insert can maintain stability

Question 42

Dynamics

Answer 42

The product of the static stiffness and damping. Maximizing dynamics leads to stability