Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MEC 322 > Metrology > Flashcards

Metrology Flashcards

slay the midterm

1
Q

Metrology is…

A

a science of measurement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Metrology includes…

A

all theoretical and practical aspect of measurement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what factors determine performance of product (other than mechanical and physical properties)

A

dimensions and tolerances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Definition of Dimensions

A

linear or angular sizes of components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Definition of Tolerances

A

allowable variation with NO effect on performance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

dimensions on part drawings represent…

A

nominal or basic sizes of the part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

when do variations occur?

A

occur in any manufacturing process (manifested as variations in part size)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are tolerances used for?

A

used to define limits of allowed variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

If tolerance is too small what does it cost?

A

it costs ALOT, cost is high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how much does tolerence shrink every 10 years

A

shrinks by a factor of 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Can parts from the same machine be different?

A

Yes.
1. speed of operation *
2. temperature *
3. lubrication
4. difference of incoming material *

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is bilateral tolerance

A

Two, variation in both positive and negative direction from nominal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Unilateral Tolerance?

A

One, either positive OR negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Limit dimention?

A

Max dimension and min dimension, tolerance is the difference.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

interference fit

A

you have to force it (shaft bigger than hole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Transition fit

A

fit with small clearance or
interference that allows for accurate location of
mating parts
(shaft and hole are practically the same)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

clearance fit

A

smaller than hole (fits easily and allows for rotation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the 3 types of tolerance

A
  1. Bilateral (balanced and unbalanced)
  2. Unilateral (only one)
  3. limit dimension (max and min dimension)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Allowance

A

the specific difference in
dimensions between mating parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Basic size

A

dimension from which limits of
size are derived

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Clearance

A

the space between mating parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Datum

A

theoretically exact axis, point, line or
plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Fit

A

the range of looseness or tightness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Interference

A

negative clearance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Geometric tolerancing

A

tolerances that involve
shape features of the part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Feature

A

Physically identifiable portion of a
part, e.g. hole, slot, pin, chamfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

MMC (maximum material condition)

A

condition where a feature of size contains the maximum
amount of material within the stated limits of size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is Positional tolerancing system

A

A system of specifying the
true 1.position, 2.size, and 3.form of the feature of a
part, including allowable variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the three parts of a metallic part surface

A
  1. surface texture
  2. altered layer (sub surface layer)
  3. substrate (bulk)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

which part from metallic part surface is most important and why

A

Altered layer/ subsurface layer… because it affects the functioning of the product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Surface roughness equations

A
  1. Ra = roughness average = (a+b+c..)/n
  2. Rq = root mean square = sqrt[(a^2+b^2…)/n]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Surface texture

A

repetitive/ random deviations from the nominal surface of an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q
  1. Lay
A

predominant direction or pattern of the surface texture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q
  1. roughness
A

zoomed in variations (determined by material characteristics and process)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

the 7 types of Lay

A

= parallel
⊥ perpendicular
x both direction in an angle
M Multi directional
C circular to center
R radial relative to center
P particulate, nondirectional or protuberant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Equation for surface-roughness measurement

A
  1. Ra = roughness average = (a+b+c+…)/n
  2. Rq = rooughness root mean square = sqroot[(a^2+b^2)/n]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q
  1. Flaws
A

irregularities that occasionally occur on surface. includes; cracks, scratches inclusions. (relate to surface texture but can affect surface integrity)

38
Q
  1. waviness
A

zoomed out variations (deviations due to work deflection, vibration, heat treatment, and similar factors)

39
Q

What are the 4 elements of surface texture

A
  1. roughness
  2. waviness
  3. lay
  4. flaws
40
Q
  1. Lay
A

predominant direction or pattern of the surface texture

41
Q

surface roughness

A

measurable characteristic based on roughness deviations

42
Q

the 7 lay symbols

A

= parallel
⊥ perpendicular
X angular in both directions
M multidirectional
C circular relative to center
R radial relative to center
P particulate, nondirectional or protuberant

43
Q

Surface finish

A

subjective term denoting smoothness and general quality of surface

44
Q
  1. Flaws
A

irregularities that occur occasionally on the surface, relate to surface texture but also effect surface integrity. (cracks, scratches, inclusions, and defects in surface)

45
Q

What are 4 elements of surface texture

A
  1. Roughness
  2. Waviness
  3. Lay
  4. Flaws
46
Q

Cut off length

A

used as a filter between waviness roughness and waviness (cut off length is shorter than the waviness)

47
Q

Surface Integrity

A

study of subsurface (altered) layer and changes
that occur during processing which may influence performance of finished product

48
Q

4 types of energy that cause surface changes

A
  1. mechanical energy
  2. thermal energy
  3. chemical energy
  4. electrical energy
49
Q

surface changes caused by mechanical energy

A
  • residual stresses (causes week points
  • hardness variations (after applying mechanical force it becomes much harder)
  • cracks (micro & macroscopic)
  • voids or inclusions
50
Q

surface changes caused by thermal energy

A
  • metallurgical changes
  • redeposited
  • resolidified material
  • heat affected zone in welding
  • hardness changes
51
Q

surface changes caused by Chemical energy (fast production, commonly used)

A
  • intergranular attach (corrosion and oxidation)
  • chemical contamination
  • absorption of certain elements such as h and CI in metal surface
  • slective Etch
  • alloy depletion and resulting hardness changes
52
Q

surface changes caused by electrical energy

A
  • change in conductivity/magnetism
  • craters (rough surface depression left in the surface)
53
Q

a better surface finish requires..

A

more money because it requires more operations and time. processes include horning, lapping, polishing and superfinishing.

54
Q

Measurement

A

Procedure in which an unknown quantity is
compared to a known standard, using an
accepted and consistent system of units

55
Q

In manufacturing what quantity is most focused on

A

Length quantity

56
Q

Accuracy

A

closeness of agreement between an observed value and standard (systematic error)

57
Q

Precision

A

closeness of agreement between randomly selected individual measurements (random error)

58
Q

Magnification

A

amplification

59
Q

Sensitivity

A

resolution (smallest difference in dimension)

60
Q

Rule of 10

A

measuring tool is 10 times accurate than the tolerance ur measuring

61
Q

Stability (drift)

A

ability to maintain calibrated status

62
Q

what is the standard measuring temperature?

A

20 degrees Celsius

63
Q

Repeatability is the

A

equipment variation (same person using the same instrument)

64
Q

Reproducibility

A

operation variation (different people using the same instrument)

65
Q

Calibration

A

comparing a measuring device to one having a known relationship to national standards

66
Q

What are the 2 types of inspection

A
  1. inspection by variables
  2. inspection by attributes
67
Q

1.Inspection by variable

A

product dimensions are measured by appropriate measuring instruments

68
Q
  1. Inspection by attributes
A

pass or fail but we don’t know specifics (yes or no to a standard)

69
Q

Contact vs. Non-Contact

A

contact is cheaper and non contact is expensive (lasers and light; x-rays, ultrasounds)

non contact is used for when u cant touch the product

70
Q

Inspection/ testing points

A
  1. receiving inspection
  2. in-process inspection
  3. final inspection
71
Q

100% manual inspection is…

A

100% manual inspection is not 100% good quality product

72
Q

Automated 100% inspection gives ________ feedback

A

continuous

73
Q

Acceptance Sampling

A

choosing a sample and deciding if the whole thing is valid or not

74
Q

What is the economic model, breakeven analysis

A

p*c2 = C1

c1=cost of inspection
c2=cost of repair
p=true fraction nonconforminf

75
Q

when do you use 100 % inspection

A

if p> c1/c2

76
Q

when do you do nothing

A

if p < c1/c2

77
Q

What are the 2 types of measuring instruments?

A
  1. Graduated measuring (inspection by variable)
  2. Nongraduated measuring (inspection by attribute)
78
Q

what is a nongraduated tool

A

a simple caliper (just compares)

79
Q

what are graduated tools

A

gauge blocks, vernier caliper, micro meter, and ruler

80
Q

What does a dial gauge measure?

A

parallelism, straightness, roundness

81
Q

what is the equation for variation in parallelism, perpendicularity and angularity

A

V=dR/D

d = distance in question (actual)
R = dial guage value
D = distance dial gauge traveled
(doesnt exceed tolerence)

82
Q

3 tool used to measure angles

A
  1. squares
  2. sine bars
  3. protractors
83
Q

Sine bar equation and use

A

sin A = Height/Length

stack gauge blocks (heights) till sine bar makes perfect contact with angle being measured

84
Q

Optical flats, determining fringe spacing and angles equation

A

Fringe spacing = λ/2sinθ

85
Q

Coordinate Measuring Machines (CCM) measures 5 and etc

A
  1. length
  2. angles
  3. dimensions
  4. flatness
  5. roundness
    (highly accurate and sensitive)
86
Q

what are the 3 styles of CMM

A
  1. Gantry style CMM (most accurate)
  2. Horizontal Atm CMM
  3. Articulate Arm CMM (least accurate)
87
Q

CMM - touch probes (end effector); 3 main configurations

A
  1. fixed (solid material)
  2. touch triggered (on contact measures by sending electrical signal)
  3. optical (least accurate, use active light to measure distance)
88
Q

What do u have to do whenever u change a probe?

A

CALIBRATE!!!

89
Q

CMM - part datums

A

is the principle axis of the part (defined on machine)

90
Q

What does laser stand for

A

Light
Amplification by
Stimulated
Emission of
Radiation

91
Q

the 4 machine vision applications

A
  1. inspection
  2. part identification
  3. visual guidance and control
  4. safety monitoring
92
Q

Machine vision inspection is

A

90% of all industrial machine vision applications

MEC 322 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions