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Study Questions > Metalworking > Flashcards

Metalworking Flashcards

0
Q

What two primary functions do cutting fluids perform?

A

Cooling

Lubrication

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1
Q

Name three general classifications of fluids used in cutting and grinding.

A 
Soluble oils (petroleum, semi-synthetic, full synthetic)
Neat oils
Tri-purpose oils
Mineral cutting oils
Chemical or synthetic coolants
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2
Q

What is the most important characteristic of a soluble oil?

A

It must mix easily with water to form a stable emulsion.

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3
Q

The primary function of a soluble oil emulsion in metalworking is as a ___________.

A

Coolant

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4
Q

In order to form a stable emulsion of oil and water, which should be added to which?

A

Oil is added slowly to water (remember to put the water in the bathtub first before you get in!) OIL-IN-WATER

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5
Q

Why does hard water make it difficult to form a stable emulsion?

A

Minerals (calcium & magnesium) in the water react with emulsifiers to form insoluble soaps.

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6
Q

Water with a hardness of more than ______ ppm is considered hard.

A

300

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7
Q

List best practices to prevent degradation and odors in oil soluble fluids.

A

Keep the fluid aerated and circulating.
Monitor the condition of the fluid and add biocide as necessary.
Make sure the reservoir and lines are clean and free of bacteria and fungus before adding new oil.
Remove tramp oil.
Keep the system clean and free of contamination.

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8
Q

What is the primary problem encountered with bacteria growth in oil emulsions?

A

Odor.

Also rust, corrosion of oil way, filter plugging and dermatitis.

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9
Q

What is skimming of metalworking fluids?

A

Removal of tramp oil from the top of a soluble oil by means of a belt or other mechanical skimmer.

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10
Q

Name four advantages of tri-purpose cutting oils.

A

1) Reduce inventory by consolidating lubricants
2) Eliminates tramp oil in cutting oil
3) No possibility of mixing the cutting oil (coolant) and the lubricating oil and putting one into the wrong application
4) Eliminates cross contamination of oils
5) May be used on ferrous & non-ferrous metals
6) Eliminates cutting oil dilution & resultant decreased performance

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11
Q

What material has been used as one of the most effective extreme pressure additives for heavy- duty cutting?

A

Active sulfur

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12
Q

What is the primary effect on a work-piece of using fatty additives in cutting fluids?

A

Smoother finishes (fatty oils are active at lower temperatures than chlorine or sulfur)

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13
Q

Most EDM (electrical discharge machining) processes are performed with the work-piece submerged in a light petroleum fluid called the ______ fluid.

A

EDM (electrical discharge machining)

The fluid has a very low viscosity and high dielectric strength.

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14
Q

The ____________ is generally regarded as the primary machine tool and the “father” of all others.

A

Lathe

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15
Q

What is a slushing oil?

A

A temporary rust preventive applied to steel in process.

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16
Q

What is the difference between high speed quenching and marquenching?

A

In high speed quenching, hot metal is immersed into a low to moderate temperature bath (< 300°F) to control cooling and hardness of the metal.
Marquenching uses a higher temperature bath and a more viscous fluid.

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17
Q

What are ways to stop a cutting coolant from misting?

A

Use a fluid with an anti-mist additive, change from high pressure, low volume flow of fluid to low pressure, high volume flow.

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18
Q

The primary metalworking operations performed on a lathe are ______ ___ _______.

A

Turning and boring

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19
Q

Name three other specific operations that can be performed on a lathe.

A

Threading Reaming
Facing Polishing
Drilling Knurling

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20
Q

Single or multi-spindle fully automated machine tools intended for mass production are generically called ___________.

A

Automatics

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21
Q

The machine tool capable of compound cutting motions and generally used to produce complex three dimensional shapes is the _______ ______.

A

Milling machine

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22
Q

Name two basic types of cylindrical grinders?

A

Center type

Centerless type

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23
Q

Center type grinding where the width of the grinding wheel is equal to the length of the cylindrical surface being ground is called ________grinding.

A

Plunge

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24
Q

Parts such as long shafts, hollow wrist pins, etc. that can’t be ground on a center type grinder are normally ground on what type of grinder?

A

Centerless

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25
Q

What is the primary difference between a shaper and a planer?

A

With a shaper the workpiece is clamped to a stationary table and the tool moves across. On a planer the tool is stationary and the workpiece moves past the tool.

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26
Q

A __________is a cutting tool that is pushed or pulled past or through the workpiece to produce a machined surface that conforms to the shape of this tool.

A

Broach

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27
Q

The relatively new machine tool that will, in one setup, perform several machining operations on several surfaces of a workpiece, including automatically selecting the proper tool from a storage magazine, is generally called a ________ ________.

A

Machining center

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28
Q

Name at least eight machining operations that a machining center can perform?

A

Turning Milling
Boring Drilling
Threading Spotting
Facing Knurling
Counterboring Tapping

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29
Q

Name four major benefits of machining centers?

A

Fewer machine tools needed in shop
Faster production of parts
Can produce parts with finer tolerances
Fewer machine tool operators needed

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30
Q

Name the five major types of lubricants used in and on machine tools?

A 
Way lubricants 
Gear lubricants 
Hydraulic oils 
Greases 
Metalworking fluids / coolants
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31
Q

The metal removal process by which EDM machines operate is called ___________ _________ ___________.

A

Electrostatic discharge machining

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32
Q

In the EDM process, the tool anode is the _____________ and the cathode is the ______________.

A

Workpiece

Tool

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33
Q

Name five desirable properties of dielectric fluids?

A

Reasonably high flash point for safety
Low viscosity for fluidity and fast settling of fines
Capacity for convective cooling
Unobjectionable odor
Allow passage of high peak discharge current when ruptured

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34
Q

In machining what are the two fundamental physical processes?

A

Formation of the chip

Movement of the chip over the tool

35
Q

In machining, the tool cutting through the workpiece generates heat through what two sources?

A

From frictional resistance of the tool moving across the workpiece From deformation for metal

36
Q

Name four other functions that cutting fluids should perform?

A

Protect machines, tools and other parts from rust
Must not discolor machined parts
Should not produce smoke or mist
Must not have disagreeable odor

37
Q

In some mild machining operations, especially with aluminum or other non-ferrous metals, low viscosity _________mineral oils may be used.

A

Straight

38
Q

For many severe heavy duty machining operations, a fluid with __________ __________ additives is required.

A

Extreme pressure

39
Q

List at least five additives commonly used in metal working fluids?

A

Antioxidant Metal deactivators
Extreme pressure Tackiness agent
Rust inhibitor Odor control agent
Foam inhibitor Pour point depressant
Emulsifier

40
Q

For many years, ________has been used as one of the most effective extreme pressure additives for heavy duty cutting oils.

A

Sulfur

41
Q

What is the primary advantage of transparent cutting oil?

A

Operator can see the tool and workpiece.

42
Q

Tri-Purpose cutting oils serve what three functions on automatic screw machines?

A

Cutting Fluid
Machine tool lubricant
Hydraulic fluid

43
Q

Soluble oils are not soluble, but many more appropriately be called __________ oils.

A

Emulsifiable

44
Q

What are two important characteristics of a soluble oil?

A

Emulsify easily

Form stable emulsion

45
Q

In an emulsion, the liquid which is broken up into globules is called the ________phase while the surrounding fluid is the __________phase.

A

Dispersed (internal)

Continuous (external)

46
Q

Soluble oil emulsions used for metalworking are normally what type? Give brief description.

A

Oil-in-water

The oil is the internal (dispersed) with the water being the continuous (external) phase.

47
Q

A soluble oil emulsion in which the water is dispersed and the oil is in the continuous phase is called an ________emulsion.

A

Invert

48
Q

Invert emulsions are sometimes used in what kind of application?

A

Fire resistant hydraulic fluids

49
Q

What kind of water condition makes it easier to form stable emulsions?

A

Soft water

50
Q

Describe the emulsion mixture (blend) for soluble oil emulsions used in grinding? Why is it used?

A

Lean

Provides better cooling & settling of chips and fines.

51
Q

Heavy duty soluble oils generally contain ________viscosity base oils.

A

Higher

52
Q

The key to preparing a stable soluble oil emulsion is in the proper _______.

A

Mixing

53
Q

Name the four steps in preparing a stable oil emulsion?

A

Use clean, soft water
Use clean containers for mixing
Water and oil should be approximately room temperature
Add oil into water slowly and stir continuously

54
Q

What two minerals are normally found in appreciable amounts in hard water?

A

Calcium

Magnesium

55
Q

Describe the predominant characteristic of soluble oil emulsions and chemical coolants?

A

Coolant with little lubricity

56
Q

To improve lubricity the oil content of an emulsion should be _________ .

A

Increased

57
Q

In what type of operation are cutting oils containing EP additives more effective?

A

Slow speed with heavy cuts

58
Q

What is the primary result of using fatty oils in cutting fluids?

A

Improve surface finish

59
Q

What two primary actions should be taken to reduce built-up edge of cutting tools?

A

Use a cutting fluid with more sulfur &/or chlorine.

Increase cutting speed

60
Q

Carbide and ceramic cutting tools perform best at ______cutting speeds.

A

High

61
Q

What type of metalworking fluids are usually used with carbide and ceramic tools? Why?

A

Soluble oils or chemical coolants

Cooling is more important than lubricity

62
Q

What type of metalworking fluids should never be used on magnesium?

A

Those that contain water

63
Q

Name three primary characteristics that a good gun drilling / deep hole drilling / trepanning drilling fluid possess?

A

Low viscosity – cooling and chip removal
Some EP for use on hard materials
Fatty oil for good surface finish

64
Q

Explain why machine operators should be encouraged to NOT spit or pour old coffee into the soluble oil returns through?

A

Provides good culture medium for bacteria growth.

65
Q

What is the primary complaint encountered with bacteria growth in oil emulsions?

A

Obnoxious odor

66
Q

A built up edge on the cutting tool is caused by ______ __ _____ __ ___ ____ _____.

A

Welding of metal to the tool point

67
Q

Name three characteristics of a good way lubricant?

A 
Good lubricity
Tackiness to prevent squeeze out 
Prevent stick slip 
Rust protection 
Easy pumpability
68
Q

If you must dilute a soluble oil emulsion to make it leaner, should you add water to the emulsion? WHY?

A

NO

Properly mix leaner emulsion outside the machine and add slowly to the emulsion reservoir.

69
Q

In general, ______viscosity fluids are used with slower speed applications and _______viscosity fluids are used with higher speed applications.

A

Higher

Lower

70
Q

What is the most important prevention of dermatitis for machine operators?

A

Personal Hygiene

Cleanliness

71
Q

Can dermatitis be caused by the cutting fluid itself? Explain?

A

Yes

Some people may develop sensitivity to fluids and / or additives

72
Q

Besides the fluids themselves, name three other things which may cause dermatitis or skin irritations?

A

Metal shavings and fines in the fluid
Bacteria in the fluid
Contaminants in the fluid

73
Q

Which type of metalworking fluids are most susceptible to bacterial contamination? Explain?

A

Soluble / Emulsifiable oils

The bacteria / fungi live in the water phase and feed on hydrocarbons and contaminants in the absence of oxygen.

74
Q

Name the major types of lubricants used in and on machine tools.

A 
Coolant
Way lubricant
Hydraulic oil
Grease
Spindle oil
Gear oil
75
Q

What are some methods of controlling odor in soluble cutting fluids?

A

Keep the fluid aerated and circulating.
Monitor the condition of the fluid and add biocide as necessary.
Make sure the reservoir and lines are clean and free of bacteria and fungus before adding new oil.
Remove tramp oil.
Keep the system clean and free of contamination.

76
Q

What are three types of dermatitis? Contact, allergic, skin injury, chronic, acute

A 
Contact
Allergic
Skin injury
Chronic
Acute
77
Q

Which metals are more likely to cause human skin disorders?

A

Nickel
Chromium
Cobalt

78
Q

What is BUE?

A 
Built up edge
Metal becomes attached to cutting tool just above the point of contact with the work piece. 
Reduce BUE (built up edge) with additional EP additives.
79
Q

What are the three things to look for in a water-soluble hydraulic fluid filter plugs.

A

Soap scum
Fungus or mold
Dirt and debris

80
Q

What three things would you monitor in an in-service water-soluble oil?

A

Microbial growth
Water content
PH

81
Q

What is a machinability rating?

A

Rating assigned to metals that indicates machining difficulty based on tool life, chip size, surface finish, power consumption.

82
Q

What is a refractometer?

A

Checks concentration of oil in soluble oils.

83
Q

What is tramp oil?

A

Machine oil such as hydraulic oil or way oil that ends up in the metal working fluid.

84
Q

Machine tool ways require oils with ________ additives.

A

Stick slip

85
Q

What is the G-ratio in relation to grinding applications?

A

The ratio of the volume of metal removed to the volume of grinding abrasive consumed.

86
Q

What types of additives are used in cutting oils to reduce heat from boundary lubrication?

A

EP additives such as sulfur and chlorine.

Study Questions (17 decks)

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