Chapter 16

Question 1

What two factors decide characteristic part geometery

Answer 1

Relative motion b/w tool and workpart.

Shape of the cutting tool

Question 2

What is generating

Answer 2

Generating - part geom determined by feed trajectory of cutting tool

Question 3

What is forming (3)

Answer 3

Forming - shape of cutting tool determines the geometry of the part.

Form turning, drilling, and broaching

Question 4

What is turning? Name some (9).

Answer 4

Single point cutting tool.
Rotate the workpiece.
Lathe.

Facing, taper turning, contour turning, form turning, chamfering, cutoff, threading, boring, drilling

Question 5

What is a turret lathe

Answer 5

Six tools instead of the tailstock.

High production that requires sequence of cuts

Question 6

What is chucking machine

Answer 6

Chuck hold workpart.
Operator only load/unloads parts.
Short, light weight parts

Question 7

What is a bar machine

Answer 7

Collet hold workpart usually a bar.
Cutoff after operation.
Highly automated. CNC.

High prod of rotational parts

Question 8

What is an automatic screw machine

Answer 8

Same as bar machine but smaller.

High prod of screws and similar hardware items

Question 9

What are multiple spindle bar machines

Answer 9

> 1 spindle

Multiple parts machined then rotated.

Question 10

What is the six spindle bar machine process

Answer 10

Feed stock.
Turn main D
Form second D and spotface
Drill
Chamfer
Cutoff

Question 11

State Chuck for lathe (2)

Answer 11

3 Jaw
Easy to locate. Self centering. Only round part.

4 Jaw
Long time to locate. Rect part. Eccentric turning.

Question 12

State Lathe steadies or rests

Answer 12

Steady Rest and Follower rest

Support long jobs.

Question 13

Lathe Centres

Answer 13

Support at tailstock.

Dead centre or revolving centre

Question 14

Explain boring

Answer 14

Inside diameter of existing hole to make larger. Horizontal or vertical

Question 15

Explain Drilling and simlilar (6)

Answer 15

Creates a round hole unlike boring.

Reaming, tapping, counterboring, countersinking, center drilling, and spot facing.

Question 16

How to hold workpart for drill presses? (3)

Answer 16

Vise - two jaws

Fixture - Custom-designed for part

Drill jig - custom-designed and guides the tool during drilling

Question 17

What is milling? Explain difference b/w peripheral and face

Answer 17

Workpart moves; multiple cutting edges tool fixed.

Peripheral - Cutter axis parallel to surface

Face - Cutter axis perpendicular to surface.

Question 18

Name peripheral mills (5)

Answer 18

Slab
Slotting
Side
Straddle
Form

Question 19

Name face mills (6)

Answer 19

Conventional
Partial
End
Profile w/ end mill
Pocket
Contour

Question 20

Name the two mills

Answer 20

Horizontal - peripheral

Vertical knee-and-column

Question 21

What is a machining center?

Answer 21

3, 4, 5 axes. CNC control. Automated.

Question 22

Mill-turn center vs conventional turning center (2)

Answer 22

Position cylindrical part at an angle. Includes rotating tool spindles.

Question 23

Process of Mill-turn center (4)

Answer 23

Turn second D
Mill flat
Drill hole
Cutoff

Question 24

Diff b/w down and up milling

Answer 24

Down: Same direction as workpart. Good surface finish.

Up: Opposite direction of workpart. More safe since amount of material taken off smaller so less chance of breaking tool.

Question 25

Diff b/w shaping and planing (3)

Answer 25

Shaping: Workpart moves feed. Smaller pieces 1 to 2m.

Planing: Tool moves feed. Large pieces 10m. Only stroke cuts so not efficient

Question 26

Explain broaching process and characteristics (6)

Answer 26

Seq. - Roughing, semi-finishing, and finishing teeth.

Internal or external
Good finish, accurate dim, expensive but one pass. Made from steel since mainly tension, starter hole and through features only

Question 27

Explain sawing. Name saws (3)

Answer 27

Cuts narrow slit in work.

Power hacksaw - linear reciprocated/one direction. Short, rigid

Band Saw - Linear continuous motion. Flexible, irregular shape, aluminum

Circular Saw - Rotating saw. Continuous. Ceramic.

Question 28

Describe teeth type

Answer 28

Straight - Copper or brass

Raker - Steel and iron

Wave - Thin sheet

Question 29

Describe Filing. Name four.

Answer 29

Fine wide teeth. Small chips. Finishing/deburring

Single, Double, Rasp, Vixen

Question 30

Name three burs

Answer 30

High speed steel
Carbide
Rotary

Question 31

What is HSM: DN ratio

Answer 31

Bearing bore diameter mult by max spindle speed

1 mil to half a mil

Question 32

What is HSM: HP/RPM

Answer 32

Ratio of hp to max spindle speed.

Question 33

Req. for high speed machining (6)

Answer 33

Special bearing
High feed rate
CNC controls
Balanced tools
Coolant delivery that give higher pressure
Chip control

Question 34

What determines surface roughness? (3)

Answer 34

Geometric factors - Type of machining operation. Tool geom and feed.

Work material factors - Built-up edge effects. Crack in surf or friction b/w flank and surface.

Vibration and machine tool factors - Tool chatter. Backlash in feed mechanism.

Question 35

How to avoid tool chatter (5)

Answer 35

Dampen or stiffen
Speeds not within natural frequence.
Reduce feeds and depths
Change cutter design
Cutting fluid.

Question 36

Product design guidelines

What to avoid and what to have

Answer 36

close tolerances
good surface finish

Avoid sharp corners, edges and points. Avoid anything that can’t be achieved with standard cutting tools.

Choose material with good machinabilty since shorter and cheaper to produce