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Manufacturing Yutrzenka > Manufacturing Exam 1 Yutrzenka > Flashcards

Manufacturing Exam 1 Yutrzenka Flashcards

1
Q

Primary industry

A

cultivate and exploit natural resources.

Ex. farming and mining

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2
Q

Secondary industry

A

Uses primary industry goods

Ex. manufacturing, construction

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3
Q

Tertiary industry

A

service sector

Ex. banking

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4
Q

What are the 2 types of manufacturing processes

A

Processing and assembly operations

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5
Q

What is a processing operation

A

transform a material to one state of completion to a more advanced state

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6
Q

What are assembly operations

A

join 2 or more components to create a new entity

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7
Q

Can copper be welded? Why or why not?

A

Copper cannot be welded because of heat transfer

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8
Q

Can cast iron be welded? Why or why not?

A

Cast iron cannot be welded because of heat transfer

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9
Q

What is cast iron composed of

A

iron and >2% carbon

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10
Q

What is metal composed of

A

iron and <2% carbon

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11
Q

Types of processing operations

A
  1. Shaping- alter geometry
  2. Property enhancing- improve physical without chaning shape
  3. Surface processing
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12
Q

Types of shaping operations and descriptions

A
  1. Solidification- starting material is heated liquid or semi fluid
  2. Particulate - starting material is powder
  3. Deformation- starting material is ductile solid (mostly metal)
  4. Material removal - starting material is ductile or brittle solid
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13
Q

What are property enhancing processes, what are the types?

A

Property enhacing processes do not change the shape

Heat treatment- of metals and glass, play with time and temperature.
Sintering - of powdered metals and ceramics

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14
Q

What are types of surface processes?

A

Cleaning
Surface treatments- sandblasting, carburizing
Coating and thin film deposition

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15
Q

What are the 2 types of assembling processes and describe them

A

Joining processes- create a permanent joint. Ex. welding, brazing, soldering

Mechanical assembly - fastening by a mechanical assembly. Ex. bolts, threaded fasteners, screws

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16
Q

What is welding

A

combining 2 or more parts by heat and/or pressure

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17
Q

Heat, pressure, or both

4 types of welding

A

stick- heat only
friction welding- heat and pressure
cold welding- pressure only
tick- without filler

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18
Q

Faying surface

A

the part surfaces in contact or close proximity that are being joined

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19
Q

2 categories of welding and describe them

A

Fusion- melting and coalescing material by means of heat, supplied by fuel gas, electricity, or high energy beams

Solid state- joining without fusion, no liquid phase in joint
- used for aluminum to steel for example
because they have different melting points

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20
Q

How to prevent oxidation in welding

A

flux or shielding gas

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21
Q

What is an autogenous weld

A

when no filler metal is used

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22
Q

Brazing

A
  • melting a filler metal distributed by capillary action
  • no melting of base metal
  • surfaces to be brazed must be pre-cleaned so they remove oil/dirt
  • Filler metal(Tm) is greater than 450C (840F)
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23
Q

Capillary action

A
  • ability of liquid to flow in narrow spaces without the help of and in opposition to external forces (gravity)
  • occurs when the adhesion to the walls is stronger than the cohesive forces between liquid molecules
  • a narrow tube will draw a liquid column greater than a wider tube will
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24
Q

Equation for capillary height

A

h = (2T) / (rhorg)

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25
Q

Base metals and filler metals for brazing

A

Base metals - filler metals

  • aluminum - aluminum and silicon
  • coppper - copper and phosorous
  • steel, cast iron - copper and zinc
  • stainless steel - gold and silver
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26
Q

What is brass composed of

A

70% copper, 30% zinc

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27
Q

Typical brazing clearances

A

.025 to .25mm
or
.001 to .01 in

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28
Q

what does HAZ stand for

A

heat affected zone

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29
Q

Use brazing and soldering over welding when

A
  • metals have poor weldability
  • dissimilar metals need to be joined
  • the intense heat of welding may damage components
  • geometry of joint is not suitable for welding, faying surface not accessible
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30
Q

Brazing limitations

A
  • joint strength is lower than welded joint
  • joint strength is lower than base metal
  • higher service temp may weaken a brazed joint
  • color of brazing metal may not match color of base metal
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31
Q

Characteristics of good flux

A
  • low melting temp
  • low viscosity so it can be displaced by filler metal
  • protects joint until solidification of filler metal
  • easy to remove after brazing
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32
Q

Heating methods for brazing

A

torch
furnace
resistance- heated by electrical resistance in parts
dip- molten salt bath (flux)

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33
Q

Applications of brazing

A

Automotive, electrical, jewelry, plumbing

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34
Q

How is soldering different from brazing?

A 
Application and temp
Filler metal(Tm) with <450C (840F) is distributed by capillary action
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35
Q

Typical clearances for soldering

A

.075 to .125mm

.003 to .005 inches

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36
Q

Soldering advantages

A
  • less energy than brazing or welding
  • variety of heating methods
  • easy repair
  • good electrical and thermal conductivity
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37
Q

Soldering disadvantages

A
  • low joint strength

- joint weakens or melts at elevated temps

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38
Q

Solder materials

A

alloys of tin and lead

  • lead is poisonous
  • tin- chemically active at soldering temps and promotes wetting temps
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39
Q

Function of soldering fluxes

A
  • be molten at soldering temperature
  • remove oxide films and tarnish from base part surfaces
  • prevent oxidation during heating
  • promote wetting of faying surfaces
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40
Q

What is usually done when soldering sheet metal joints

A

sheets are bent and interlocked before soldering to increase joint strength

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41
Q

Thermit welding

A

mixture of aluminum powder and iron oxide that produces an exothermic reaction when ignited

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42
Q

Thermit reaction

A

8Al + 3Fe3O4 into 9Fe + 4Al2O3 + heat

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43
Q

What is the process of thermit welding

A
  1. superheated iron is contained in a crucible located above the joint to be welded
  2. Crucible is tapped
    3.
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44
Q

Arc welding definition

A

fusion welding process in which joining of metals is achieved by the heat from an electrical arc between an electrode and the work

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45
Q

Temperature in arc welding

A

10,000F (5500C), can melt any metal

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46
Q

Most arc welding processes add ________ to increase volume and strength

A

filler metal

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47
Q

What is arc welding called without filler metal

A

autogenous welding

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48
Q

Electric arc

A
  • discharge of electric current across a gap in a circuit

- it is stabilized by an ionized column of gas(plasma) through which current flows

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49
Q

Problems with manual welding

A

weld quality and productivity

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50
Q

Arc time

A

time arc is on divided by hours worked

- time is wasted setting up/cleaning

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51
Q

What are a typical manual and machine arc welding time

A

manual 20%

machine 50%

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52
Q

2 types of arc welding electrodes

A

Consumable- source of filler metal in arc welding

Nonconsumable- Filler metal is added separately if used. Ex. tungsten

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53
Q

What is arc shielding

A

Using gas or flux to prevent weld from oxidation

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54
Q

What are typical shielding gases

A

Ar, He, CO2

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55
Q

What is STICK welding

A
  • shielded metal arc welding
  • uses consumable electrode consisting of a filler metal (rod or stick) coated with chemical that provide flux and shielding
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56
Q

If cooling rate of a weld is high, the brittleness is

A

high

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57
Q

T/F: Composition of filler metal is similar to base metal in SMAW (Stick) welding

A

True

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58
Q

Pros and cons of stick welding

A 
Pros
- equipment is portable and low cost
- very versatile and most widely used
- application fro thickness >5mm
Cons
- Manual process
- sticks must be periodically changed
- High current may melt/burn coated prematurely
- It is seldom used for aluminum alloys, copper alloys, and titanium
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59
Q

Gas metal arc welding GMAW is known as

A

Mig (metal inert gas)

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60
Q

What type of electrode and flux is used for MIG

A

consumable (wire) and shielding gas

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61
Q

Types of arc shielding gases, what are they, and describe them

A
  1. Inert gases
    - argon- most widely used, produces finger like penetration
    - helium- high thermal conductivity, used for hotter arc, broad but shallow penetration
  2. Reactive gases
    - CO2, O2, N2, H2
    - CO2 is only one that can be used alone
    - all can be combined with argon to get binary shielding gas blends
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62
Q

What is arc shielding (flux)? The purpose?

A

Substance that prevents formation of oxide. Provides a protective atmosphere to weld, stabilizes arc, reduces splattering.

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63
Q

What are tubular electrodes?

A

flux is contained in the core and is released as electrode is consumed

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64
Q

GMAW advantages over SMAW

A 
Better arc time
better use of electrode filler
higher deposition rates
eliminates problem of slag removal
can be automated
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65
Q

Gas tungsten arc welding (GTAW)

  1. What type of electrode
  2. Common name
  3. Does it use filler metal
  4. What metals does it work with
A
  1. Uses non-consumable electrode and an inert gas for arc shielding
  2. TIG
  3. With or without filler metal
  4. Applied to most metals
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66
Q

Pros and cons of GTAW

A

Pros

  • good weld
  • no splatter
  • little post weld cleaning, be no flux

Cons

  • slower, more expensive
  • Thickness cannot be as thick as GMAW
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67
Q

Submerged arc welding (SAW)

  1. type of electrode
  2. What type of flux
  3. Can unused flux be recovered
A
  1. continuous, consumable bare wire electrode
  2. blanketed by granular flux
  3. Unused flux is recovered
68
Q

Applications of SAW

A

Weld I beams
Heavy machinery
Low carbon, low alloy and stainless steels
Must be in horizontal orientation

69
Q

Laser welding

  1. Definition
  2. Flux and does it use filler metal?
  3. What size welds
A
  1. Fusion welding process in which coalescence is achieved by the energy of a highly concentrated, coherent ligh beam focused on the joint.
  2. Uses shielding gas and NO filler metal.
  3. Small welds
70
Q

What does LASER stand for

A

Light amplification by stimulated emission of radiation

71
Q

Laser welding advantages

A
  1. similar and dissimilar metals can be welded
  2. heating and cooling rates are much higher
  3. HAZ is small
  4. Clean weld joints
72
Q

Limitations of laser welding

A
  1. Rapid cooling rates cause cracking in high carbon steels

2. High equipment costs

73
Q

Applications of laser welding

A

Electronics, medical equipment, transmission components in automoblies and cladding process

74
Q

Resistance welding (RW)

  1. Definition
  2. How is heat generated, Heat equation
A
  1. A group of fusion welding processes that use a combination of heat and pressure to accomplish coalescence
  2. Electrical resistance. H = (I^2)RT
75
Q

Advantages of Resistance welding

A
  1. no filler metal
  2. high production rates
  3. lends itself to automation
  4. lower operator skill than arc welding
  5. good repeatability and reliability
76
Q

Limitations of resistance welding

A
  1. high initial equipment cost

2. limited to lap joints for most RW processes

77
Q

Resistance spot welding

  1. Definition
  2. Used to join what?
  3. What industries is it used in
A
  1. Resistance welding process in which welding of faying surfaces of a lap joint is achieved at one location by opposing electrodes
  2. Used to join sheet metal
  3. Automobiles, metal furniture, appliances
78
Q

What type of weld is there 10,000-15,000 welds on a car frame?

A

Spot welds

79
Q

Components of resistance spot welding

A
  1. 2 opposing electrodes
  2. means of applying pressure to squeeze parts between electrodes
  3. Power supply from a controlled environments
80
Q

Resistance spot welding process

A
  1. parts inserted between electrodes
  2. electrodes on
  3. current on
  4. current off
  5. electrodes opened
81
Q

Resistance seam welding

A

Uses rotating wheel electrodes to produce a series of overlapping spot welds along lap joints
Can produce ait-tight joints

82
Q

Resistance seam welding applications

A
  1. gas tanks
  2. automotive mufflers
  3. various sheet metal containers
83
Q

Resistance projection welding

A
  1. Start of operation, contact between parts is at projections
  2. When current is applied, weld nuggets similar to spot welding are formed at projections
84
Q

Solid state welding (SSW)

  1. Is base metal melted
  2. Heat, pressure, or both
A
  1. Do not melt base metal, joining without fusion. Ex. not liquid phase
  2. Coalescene results from application fo pressure alone or a combination of heat and pressure
85
Q

Success factors in Solid state welding (SSW)

A

Very clean

in very close contact with each other to permit atomic bonding

86
Q

Advantages of Solid state welding (SSW)

A
  1. no HAZ, so metal around joints retains original properties
  2. Many Solid state welding (SSW) processes produce welded joints that bond the entire contact interface between 2 parts rather than distinct spots of seams
  3. Some Solid state welding (SSW) processes can be used to bond dissimilar metals, without concerns about relative melting points, thermal expansions, and other problems that arise in fusion welding
87
Q

Roll welding

  1. definition
  2. What do you do to the interface before welding
  3. similar or dissimilar metals
A
  1. Joining w/o fusion by dies or rolls (roller bending), plastic deformation of 1 or both parts. Think interlocking fingers)
  2. Pre-clean interface with wire or powerbrush
  3. Applied to dissimilar metals, but works best between similar metals
88
Q

Roll bonding

A
  1. Must be done in multiple # of passes

2. Pre-heat metal sheets

89
Q

Explosive welding

A
  1. Commonly used to bond 2 dissimilar metals. Ex. to clad one metal on top of base metal over large areas
  2. Contact pressure is applied by denoting a layer of explosives place over one of the mating member
  3. Kinetic energy of the flyer plate striking the mating member produces a turbulent, wavy interface, mechanically interlocking the 2 faces
90
Q

Explosive welding advantages and disadvantages

A
  1. can produce a bond between 2 metals that cannot by welded by conventional means
  2. large access area can be bonded
  3. weld is very clean
  4. large knowledge about explosives must be known
91
Q

Friction welding (inertia)

A
  1. Coalescence is achived by frictional heat combined with pressure
  2. When properly done, no melting occurs at faying surfaces
  3. Can be used for dissimilar metals
  4. Amenable to automation and mass production
92
Q

Applications of Friction welding

A
  1. shafts/tubular parts

2. automotive, farm equipment

93
Q

Limitations Friction welding

A
  1. at least one part must be rotated
  2. flash must be usually removed (extra work)
  3. Upsetting reduces part length (must be considered designing)
94
Q

Friction stir welding (FSW)

A

3rd body (small rotating pins) is rubbed against the 2 surfaces to be joined. The pin is plunged into the join, causing frictional heating, mixing, or stirring of the material in the joint. Most commonly used for butt joints of aluminum and titanium alloys in aerospace industry, now also in polymers and composites

95
Q

Friction stir welding (FSW) advantages

A
  1. superior weld strength
  2. little distortion or shrinkage
  3. good weld appearance
96
Q

Friction stir welding (FSW) disadvantages

A
  1. an exit hole is produced when tool is withdrawn
  2. heavy duty clamping is required
  3. milling machine needed
97
Q

Welding defects

A

Cracks, cavities, solid inclusions, imperfect shape, incomplete fusion

98
Q

Welding cracks

A

fracture type in weld or in base metal adjacent to weld

  • serious defect because it reduces strength
  • caused by embrittlement or low ductility of weld
99
Q

Cavities

A
  1. Porosity- small voids formed by gross trapped during solidification. Caused by inclusion of atmospheric gases, sulfur in weld, or surface contaminents
  2. Shrinkage voids- cavities formed by shrinkage during solidification
100
Q

Solid inclusions

A

Non-metallic material entrapped in weld metal

Most common is slag inclusions generated during AW processes that use flux. Instead of floating

101
Q

Incomplete fusion

A

weld beads has not fused throughout entire cross section

102
Q

Inspection and testing methods

A

visual inspection

non destructive

103
Q

Visual inspection

A

Most widely used, human inspector
Limitations
- only surface defects are detected
- welding inspector must decide if more testing is needed

104
Q

Nondestructive evaluation

A

Ultrasonic
Radiographic
Dye penetrant
Magnetic particle

105
Q

Destructive testing

A

Weld is destroyed
Mechanical test- purpose is similar to tensile testing
Metallurgical tests

106
Q

What is the reason for assembly with fasteners?

A

For maintenance/repair

107
Q

Mechanical assembly involves

A

fasteners OR shaping/reshaping of one of the components being assembled (no fasteners required)

108
Q

4 mechanical assembly methods

A
  1. threaded fasteners (screws, nuts, bolts)
  2. Rivets (permanent joint)
  3. Interference fits
  4. Other mechanical fastening methods
109
Q

Why use mechanical assembly?

A

1) Ease of assembly- minimal special tools, low skill required, short time
2) Ease of disassembly- allow for maintenance

110
Q

Describe threaded fasteners

A
  • have external or internal threads
  • in most cases, they allow for disassembly
  • most important category of mechanical assembly
  • screws, bolts, nuts
111
Q

What types of holes do screws go into?

What about bolts?

A

Screws- blind threaded holes

Bolts- through holes to connect to nut

112
Q

Setscrews

A

assembly functions such as fastening collars, gears, and pulleys to shafts.

1) collar to shaft
2) various setscrew geometries

113
Q

What is the main challenge of bolted joints?

A

Overtightening- can cause stress that exceed strength of fastener or nut

114
Q

Failure of overtightening can happen by

A

1) stripping of threads (internal or external)

2) excessive tensile stresses on cross-sectional area

115
Q

What is a washer used with/purpose

A

Used with threaded fasteners to ensure tightness of mechanical joint. Distributes stresses, provide support for large clearance hole, seals the joint.

116
Q

What are rivets

A

unthreaded head pin that joins 2 or more parts by

a) passing the pin through holes then
b) upsetting a second head in pin on the opposite side

Used for permanent joints

117
Q

Advantages and applications of rivets

A

Advantages
- high production rates, simple, dependable, cheap
Applications
- aerospace

118
Q

Types of rivets

A

solid, tubular, semi-tubular, bifurcated, compression

119
Q

What type of material are rivets made of

A

Aluminum 2024/7075

120
Q

Toolings/methods for rivets

A
  • impact- 1 blow with hammer
  • steady compression- riveting tools applies continuous squeezing
  • combination- impact and compression
121
Q

Interference fits

A

assembly methods based on mechanical interference between 2 mating parts being joined

the interference, either during assembly or after joining, holds the parts together

122
Q

Interference fit methods

A

press fitting
shrink and expansion fits
snap fits
retaining rings

123
Q

Press fitting

A

larger diameter pin into smaller hole

124
Q

Reason for press fitting

A

locating and locking components- to augment threaded fasteners by holding parts in fixed alignment with each other

pivot points- permit rotation of one component about the other

125
Q

Shrink fitting

A

external part is enlarged by heating and internal part is inserted

126
Q

Expansion fitting

A

internal part is contracted by cooling and is inserted into external part

127
Q

Uses for shrink/expansion fitting

A

Fit gears, pulleys, and sleeves onto shafts

128
Q

Snap fits

A

joining 2 parts in which mating elements possess a temporary interference during assembly, but once assembled they interlock

  • during assembly, one or both parts elastically deform to accommodate the temporary interference
  • originally conceived as a method ideally suited for industrial robots, easy for humans too
129
Q

Retaining ring, definition and use

A

fastener that snaps into a circumferential groove on a shaft or tube to form a shoulder
- used to locate or restrict movement of parts on a shaft

130
Q

Integral fastener

A

components are deformed so they interlock as a mechanically fastened joint

131
Q

Integral fastener methods

A

lanced tabs

seaming

132
Q

Keys to successful DFA (design of assembly)

A
  1. design with as few parts as possible

2. design remaining parts so they are easy to assembly

133
Q

Design guidelines for automated assembly

A
  • limit the required directions of access
    adding all components vertically is ideal
  • use high-quality components
  • minimize threaded fasteners
  • use snap-fit assembly
134
Q

Design guidelines for automated assembly

A

avoid parts that tangle

135
Q

Interference fits

A

assembly method based on mechanical interference between two mating parts being joined

136
Q

Conventional machining (cutting)

A

material removal by a sharp cutting tool

Ex. turning, milling, drilling

137
Q

Abrasive processes

A

material removal by hard, abrasive particles

Ex. grinding, lapping

138
Q

Non-traditional machining

A

mechanical, electrical, chemical, thermal, optical sources of energy

139
Q

Relative motion is required between the tool and the work piece. This comes in the form of

A 
cutting speed (primary motion)
tool feed (secondary motion)
140
Q

Cons of machining

A

wasting material

time consuming

141
Q

Machining in the manufacturing sequence

A

Generally performed after other basic manufacturing processes such as casting, forging, and bar drawing

142
Q

Turning

A

single point cutting tool removes from a rotating work piece to form a cylindrical shape

143
Q

Through hole vs blind hole

A

Through hole- drill exits opposite side of work

Blind hole- drill does not exit opposite side

144
Q

Other operations related to turning

A

threading, boring (counterboring), drilling

145
Q

Milling

A
  • work is fed past a rotating tool with multiple cutting edges
  • axis of tool rotation is perpendicular to feed direction
146
Q

Types of milling

A

peripheral milling

face milling

147
Q

Peripehral milling

A
  • cutter axis is parallel to surface being machined

- cutting edges on outside periphery of cutter

148
Q

Face milling

A
  • cutter axis is perpendicular to surface being milled

- cutting edges on both the end and outside periphery of the cutter

149
Q

Roughing vs finishing cuts

A

usually several roughing cuts are taken, followed by one or two finishing cuts

150
Q

4 types of chip in machining

A
  1. discontinuous
  2. continuous
  3. continuous chip with built-up edge (BUE)
  4. serrated
151
Q

Discontinuous chip

A
  • brittle work materials (Ex. cast iron)
  • low cutting speeds
  • large feed and depth of cut
  • high tool-chip friction
152
Q

Continuous chip

A
  • ductile work materials
  • high cutting speeds
  • small feeds and depths
  • sharp cutting edge
  • low tool-chip friction
153
Q

Continuous chip with BUE (built up edges

A
  • ductile materials
  • low to medium cutting speeds
  • tool chip friction causes portions of chip to adhere to rake face
  • BUW forms, the breaks off, cyclically
154
Q

Serrated chip

A
  • semi-continuous (saw-tooth appearance)
  • cyclical chip forms with alternating high shear strain the low shear strain
  • associated with difficult-to-machine metals at high cutting speeds (Ni-rich alloys such as stainless steel
155
Q

Chip thickness ratio

A

r = t_o / t_c

r = chip thickness ratio
t_o = thickness of the chip prior to chip formation
t_c = chip thickness after separation

chip thickness after cut is always greater than before, so chip ratio is ALWAYS less than 1

156
Q

Features of a cutting tool

A

Cutting edge - separates the chip from the work piece

Rake face - directs the newly formed chip away from the work piece, defined in terms of the rake angle (alpha)

Flank face - provides clearance between the tool and the new work surface, defined in terms of the relief angle

157
Q

Determining shear plane angle

A

based on the geometric parameters of the model, the shear plane angle (phi) can be determined as:

tan(phi) = [rcos(alpha)] / [1 - rsin(alpha)]

r = chip ratio
alpha = rake angle
158
Q

Forces action on chip

A

Friction force F and normal force N

Shear force F_s and normal force to shear F_n

159
Q

Coefficient of friction between tool and chip

Friction angle beta

A 
mu = F / N
mu = tan(beta)
160
Q

Resultant forces acting on a chip explained in next slide

A

Vector addition of F and N = resultant R
Vector addition of F_s and F_n = resultant R’
Forces action on the chip must be in balance
- magnitude of R = magnitude of R’
- R’ must be opposite in dirction to R
- R’ must be colinear with R

161
Q

Shear stress equation (machining)

A

tau = F_s / A_s

A_s = area of the shear plane

A_s = (t_o*w) / [sin(phi)]

162
Q

Shear strain equation (machining)

A

gamma = tan(phi - alpha) + cot(phi)

gamma = shear strain
phi = sheat plane angle
alpha = rake angle of cutting tool
163
Q

What forces in machining can/cannot be measured

A

cannnot - F, N, F_s, F_n

can -
F_c (cutting force in the direction of cutting)
F_t (thrust force perpendicular to the cutting force)

164
Q

Equations that relate the forces that cannot be measured with the forces that can be measured are:

A 
F = F_c*sin(alpha) + F_t*cos(alpha)
N = F_c*cos(alpha) - F_t*sin(alpha)
F_s = F_c*cos(phi) - F_t*sin(phi)
F_n = F_c*sin(phi) + F_t*cos(phi)
165
Q

The merchant equation

Of all the possible angles at which shear deformation can occur, the work material will select a shear plane angle (phi) that __________

A

minimizes energy

The merchant equation (phi)
phi = 45 + alpha/2 -beta/2

166
Q

The merchant equation (phi), what is it and what does it tell us?

A

phi = 45 + alpha/2 -beta/2

To increase shear plane angle

  • increase the rake angle
  • reduce the friction angle (or reduce the coefficient of friction)
167
Q

Higher phi means ________ shear plane which means lower shear force, cutting forces, power, and temperature

A

smaller

Manufacturing Yutrzenka (1 decks)

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