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Millwright Year 2 > Lubrication > Flashcards

Lubrication Flashcards

1
Q

What is friction?

A

Is the tendency to resist movement when two surfaces are in contact as they move.

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2
Q

List the negative effects of friction.

A
  • increases power consumption
  • causes wear
  • creates heat reducing component life
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3
Q

Name the three types of friction?

A
  • sliding friction
  • rolling friction
  • fluid friction
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4
Q

What type of friction exists within a lubricant?

A

Fluid friction.

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5
Q

What are the functions of a lubricant?

A
  • stop corrosion
  • reduce heat
  • carry away contaminants
  • help seal
  • reduce friction (wear)
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6
Q

Describe Full Film lubrication.

A

Completely separates surfaces with a continuous film.

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7
Q

What is Sliding Friction?

A

When two surfaces slide over each other.

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8
Q

Describe Boundary Film lubrication.

A

A film that does not completely separate the surfaces.

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9
Q

How does a lubricant reduce friction?

A

By separating two surfaces with a film that has less friction than the moving parts.

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10
Q

What is Rolling Friction?

A

When a spherical or cylindrical body rolls over a surface.

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11
Q

What is the Theory of Adhesion?

A

Adhesive forces cause “unlike” materials to stick together.

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12
Q

What is the Theory of Cohesion?

A

Cohesive forces cause molecules of “like” materials to stick together.

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13
Q

Oil forms in layers of ________.

A

Globules.

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14
Q

What is Viscosity?

A

The resistance to flow.

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15
Q

What five things should be considered when choosing the right viscosity lubricant?

A
  • speed (RPM)
  • load
  • temperature
  • pressure
  • environment
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16
Q

What does higher viscosity allow?

A

Greater loads to be carried.

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17
Q

What should be done to minimize power loss?

A

Use the lowest viscosity oil that is able to carry the load.

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18
Q

Name the two ways viscosity is measured?

A

Dynamic and Kinematic.

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19
Q

Dynamic viscosity is use to measure __________.

A

Fluid friction.

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20
Q

What is the most common British unit of Kinematic viscosity?

A

Centistoke (cSt).

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21
Q

Viscosity changes due to temperature are indicated by the __________.

A

Viscosity Index (VI).

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22
Q

What does a higher Viscosity Index number mean?

A

The smaller the change in viscosity due to temperature.

23
Q

What are the three main groups Additives and Inhibitors are divided into?

A
  • air control
  • water control
  • load capacity
24
Q

What is Demulsibility?

A

The ability of petroleum to separate from water upon standing.

25
Q

What is Emulsibility?

A

The ability of petroleum to mix with water using a special emulsifying agent.

26
Q

Additives that reduce wear by polishing contacting parts are called ___________.

A

Anti-wear Additives.

27
Q

Additives used for heavy load or shock load conditions are called __________.

A

Extreme Pressure Additives (EP).

28
Q

How is grease usually made?

A

By thickening lubricating oils with “soap”.

29
Q

What is the “soap” content for general use greases?

A

Between 7% - 18%. (Specialty grease can range from 3% - 50%).

30
Q

Greases made by combining a fatty acid and a base metal are called __________.

A

Simple Soap Greases.

31
Q

Name the five base metals used in simple soap greases.

A
  • calcium
  • sodium
  • aluminum
  • lithium
  • barium
32
Q

How is grease consistency measured?

A

Penetration Numbers.

33
Q

What does NLGI stand for?

A

National Lubricating Grease Institute

34
Q

What is Dropping Point when referring to grease?

A

Is the temperature at which a grease becomes fluid.

35
Q

When in a bearing, grease “shears” into thin layers and follows rotation. This is called what?

A

Directional Fluidity.

36
Q

Which is the best lubricant for heavy loads at low to medium speeds?

A

Grease

37
Q

Which is the best lubricant for high to very high speeds?

A

Oil

38
Q

When machining what is the main purpose of the lubricating cutting fluid?

A

To reduce friction.

39
Q

Which cutting oil should only be used on ferrous metals?

A

Active oil.

40
Q

Which cutting oil is used on both ferrous and non ferrous metals?

A

Inactive oil.

41
Q

What are the positive effects of friction?

A
  • provides traction
  • allows a means of polishing
  • used to start, accelerate and stop machines
  • promotes accurate tracking in bearing raceways
42
Q

What is elasto-hydrodynamic lubrication?

A

A lubricant film that forms under a loaded rolling element.

43
Q

What is the United States kinematic unit of viscosity measured by a Saybolt Viscometer?

A

Saybolt Universal Seconds. (SUS or SSU)

44
Q

What is Absolute Viscosity and how is it measured?

A

A direct measurement of the force of resistance to flow measured in centipoises.

45
Q

What is Flashpoint?

A

The lowest temperature at which the vapor above the oil will ignite with a flame passed over it.

46
Q

What type of oil was developed to solve lubricating problems that petroleum oils can’t?

A

Synthetic oil.

47
Q

What are Additives?

A

Chemicals added to the base oil to enhance performance of the oil under specific operations.

48
Q

What are Oxidization Inhibitors?

A

Additives in the oil that work to inhibit the process of oxidization.

49
Q

What are Anti-wear additives?

A

Additives that combine chemically with the surface of the metal to form a protective coating.

50
Q

What are the functions of Detergent Additives?

A
  • keeps sludge and fine deposits off metal surfaces
  • anti wear and anti scuff properties
  • clean existing deposits
  • rust inhibitor
  • controls acid
51
Q

What is the most common Solid Additive and what is its purpose?

A

Graphite and it is used as an anti-wear additive.

52
Q

What is the purpose of Pour Point Depressants?

A

To make oil flow easier at lower temperatures.

53
Q

What is the function of a Demulsifier?

A

To separate water from oil.

Millwright Year 2 (7 decks)

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