Chapter 18

Question 1

3 benefits of abrasive proc.

Answer 1

all materials
fine surface finishes
close tolerance

Question 2

abrasive material prop (4)

Two types.

Answer 2

high hardness
wear resistance
toughness
friability ( new sharp edge after fracture dull edge)

alumina: ferrous high strength alloy and steel

SiC: harder than alumina not as tough. Aluminum, brass, SS, cast iron

cBN: steel. Hardened tool steel.

Diamond: not for grinding wheel. ceramics, cemented carbides, and glass

Question 3

grain size for hard and soft work. scale.

Answer 3

hard - smaller
soft - larger
8 coarse to 250 fine

Question 4

bonding material prop (3)

Answer 4

withstand high centrifugal forces.
high temp.
resist shattering during shock loading.
hold abrasive grains rigidly.

Question 5

Wheel structure. explain.

Answer 5

volumetric prop.
Pg 50%. abrasive part.
Pb 10. bond part.
Pp 40. pore part.
1 - very dense.Pp small Pb large 
15 - very open. Pp large Pb small

Question 6

wheel grade. what used for.

Answer 6

depend on bonding particles.
soft - lose grains. low material rem rates and hard work. A grade
hard - high stock rem rates and soft materials. Z grade.

Question 7

Explain A-46-H-6-V

Answer 7

abrasive type
grit size
grade
structure
bond material

Question 8

grinding prop to get surf finish (3)

Answer 8

small grain
higher wheel speeds
denser wheel structure

Question 9

3 type of grain action

Answer 9

cutting: material removed
plowing: surface deformed and energy consumed.

Rubbing: rubbing friction. consume energy.

Question 10

temp damages from grinding (4)

Answer 10

surface burn and cracks
metallurgical damage
softening of work surf
residual stresses

Question 11

causes of wheel wear (3)

Answer 11

grain fracture: friability

attritious wear - dulling grains.

bond fracture: grains pulled out. dull grain leads to this.

Question 12

explain grinding ratio

Answer 12

GR = Vw / Vg
Vw volume of work material removed
Vg volume of grinding wheel worn

Question 13

Truing vs dressing

Answer 13

truing return disk shape and sharpens. light depth. diamond pointed tool.

dressing only sharpens.

Question 14

four type of surface grinding

Answer 14

horiz spindle. reciprocate worktable
horiz spindle with rotating worktable
vertical spindle with reciprocate worktable
vertical spindle with rotating worktable

Question 15

what is honing

Answer 15

finishing bores
fine grit sizes. great finish.
corrects holes.

Question 16

lapping. what. how. on what.

Answer 16

fluid with abrasives.
fine grits.
lenses, bearings, surfaces, gages.

Question 17

superfinishing. (4)

Answer 17

use abrasive stick against surface and reciprocating motion.

shorter strokes
higher frequency
lower pressure b/w tool and surf
smaller grit sizes.