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MENG 141 Manufacturing Processes 1 > Metal Forming Operations : Sheet Metal and Forging (Week 12) > Flashcards

Metal Forming Operations : Sheet Metal and Forging (Week 12) Flashcards

1
Q

What are some Applications of Sheet Metal?

A

Automobiles and trucks
Airplanes
Railway cars and locomotives
Farm and construction equipment
Small and large appliances
Office furniture
Computers and office equipment

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2
Q

What are some Sheet Metal Cutting Equipment and Machines?

A

Air or hydraulic-powered Shear
Foot-operated Shear
Band saw
Shear tool
Powered hand-operated tools
Hacksaw

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3
Q

What are some Sheet Metal Forming Machines?

A

Manual Bending
Press Brake machine
Wire ROlling Grooves
CNC Press Break

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4
Q

Metal Forming includes a large group of manufacturing processes in which _____________________ is used to change the shape of metal work-pieces.

A

Metal Forming includes a large group of manufacturing processes in which [plastic deformation] is used to change the shape of metal work-pieces.

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5
Q

______________ results from the use of a tool, usually a die in metal forming, which applies stresses that exceed the yield strength of the metal.

A

[Deformation] results from the use of a tool, usually a die in metal forming, which applies stresses that exceed the yield strength of the metal.

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6
Q

What is Sheet Metal?

A

A piece of metal whose thickness is between 0.006 (0.15 mm) and 0.25 inches(6.35 mm).

Anything thinner is referred to as a foil and thicker is considered a plate.

Sheet thickness is generally measured in gauge.

Sheet metal can be cut, bent, and stretched into nearly any shape.

Generally two types of operations are performed- forming and cutting.

  • Foil or leaf - extremely thin (below 0.4mm)
  • e.g. aluminum (.001”), gold leaf (.00001”)
  • Sheet metal – thicknesses in between:
  • 0.4mm (1/64 in)-6 mm (1/4in)
    • Flat
    • Coiled
  • Plate – thicknesses greater than .25” or above
    6mm
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7
Q

What are some Advantages of Sheet Metal Parts?

A
  • High strength
  • Good dimensional accuracy
  • Good surface finish
  • Relatively low cost
  • For large quantities, economical mass production operations are available
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8
Q

Sheet thickness is generally measured in gauge. The greater the gauge number, the _________ the sheet of metal

A

Sheet thickness is generally measured in gauge. The greater the gauge number, the [thinner] the sheet of metal

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9
Q

What are the three major categories of sheet metal processes?

A

o Shearing/Cutting
o Bending
o Drawing / Deep drawing

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10
Q

What is Sheet Metal Shearing?

A

Shearing is defined as separating material into two parts.

It utilizes shearing force to cut sheet metal.

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11
Q

What is Sheet Metal Bending?

A

It involves straining of a metal sheet or plate to take an angle along a (usually) straight axis.

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12
Q

What are two common bending methods?
What are the differences between them?

A
  1. V-Bending: The sheet metal blank is bent between a V-
    shaped punch and die.
  2. Edge or Wipe Bending:
    Wipe bending requires the sheet to be held against the wipe die by a pressure pad.
    The punch then presses against the edge of the sheet that extends beyond the die and pad.
    The sheet will bend against the radius of the edge of the wipe die.
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13
Q

Which of the following descriptions applies to a V-bending operation as compared to an edge-bending operation:

A. Inexpensive tooling,
B. Used for high production,
C. Used for low production,
D. None of the above

A

B. Used for high production

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14
Q

What operation is used to attach the top of an aluminum can to the body of the can?

A

Double seaming

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15
Q

What is Sheet Metal Drawing?

A

(Cup or deep drawing) Forming of a flat metal sheet into a hollow or concave shape, such as a cup, by stretching the metal.

A blank holder is used to hold down the blank while the punch pushes into the sheet metal.

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16
Q

What is Sheet Metal Deep Drawing?

A

The deep drawing process is a forming process that occurs under a combination of tensile and compressive conditions.

A flat sheet metal blank is formed into a hollow body open on one side or a hollow body is formed into a hollow body with a smaller cross-section.

17
Q

Which is the name of sheet metal operation that is more convenient to produce beverage Cans?

A

Deep Drawing

18
Q

What is Sheet Metal Punching/Blanking?

A

A piece of sheet metal is removed
from a larger piece of stock.

19
Q

The main difference between blanking and punching is that in:

-_________, the final product is removed out of the larger metal sheet, and the remaining material (the larger metal sheet) is discarded as scrap.

-whereas in __________, the material removed out is discarded, and the final product is the remaining material (the larger metal sheet).

A

-[Blanking], the final product is removed out of the larger metal sheet, and the remaining material (the larger metal sheet) is discarded as scrap.

-whereas in [punching], the material removed out is discarded, and the final product is the remaining material (the larger metal sheet).

20
Q

What is Metal Spinning?

A

Metal spinning / spin forming or spinning:

is a metalworking process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part.

Metal spinning does not involve removal of material, as in conventional wood or metal turning, but forming (molding) of sheet metal over an existing shape.

21
Q

What are the 7 basic parts of the Spinning Machine?

Which 2 are the most important?

A
  1. Mandrel
  2. Tail Stock
  3. Head Stock
    4.Spindle
  4. Clamp
  5. Forming tools
  6. Work piece
  7. Mandrel
  8. Forming tools
22
Q

What are some industries that use forged parts?

A

o Transport (automotive, aeronautics, railway, and shipbuilding);
o Military;
o Industrial machinery;
o Production energy, among others.

23
Q

Which of the following components is mainly manufactured by performing metal forging?

A. Piston
B. Engine block
C. Connecting rod
D. Crankcase

A

C. Connecting rod

24
Q

Which of the following components is mainly manufactured by performing metal forging?

A. Swing Set
B. Steel Chain
C. Street Lighting Column

A

B. Steel Chain

25
Q

What is Forging?

A

Forging: a Process in which the workpiece is shaped by compressive forces applied through various dies and tools.

Also, forging is the manufacturing process of hammering, pressing, or rolling metal into shape.

Stresses induced > Yield strength

Strain Hardening (work-hardening or cold-working): is the process of making a metal harder and stronger through plastic deformation.

26
Q

What are 5 types of Loading (Forging)?

A
  1. Compressive
  2. Tensile
  3. Bending
  4. Shear
  5. Combination of these
27
Q

Forging is the process of forming. It is of three types

What are the 3 main types of forging?

A
  1. Cold Forging
  2. Hot Forging
  3. Warm Forging
28
Q

What is Cold Forging?

A

Cold forging is generally used with soft metals, usually done at room temperature, thus below the recrystallization temperature.
𝑇 < 0.3 π‘‡π‘š

Requires greater forces and workpiece materials must have sufficient ductility at
room temperature

good surface and dimensional accuracy.

Ductility is a measure of a material’s ability to undergo significant plastic deformation before rupture.

29
Q

What is Hot Forging?

A

Hot forging is done by heating a metal to about 60-65% of its melting temperature, thus above recrystallization temperature.
𝑇 > 0.5 π‘‡π‘š π‘Žπ‘›π‘‘ π‘’π‘ π‘’π‘Žπ‘™π‘™π‘¦ 𝑙𝑒𝑠𝑠 π‘‘β„Žπ‘Žπ‘› 0.75 π‘‡π‘š

Requires smaller forces, not as good finish or dimensional accuracy; usually requires additional machining.

30
Q

What is Warm Forging?

A

It’s a combination of cold and hot forging and it’s processed around the recrystallization temperature.
0.3 π‘‡π‘š < 𝑇 < 0.5 π‘‡π‘š

31
Q

Controlled cooling may be necessary after forging to avoid distortion and to control the __________________________________.

A

Controlled cooling may be necessary after forging to avoid distortion and to control the [Microstructure of the workpiece].

32
Q

What is Recrystallization (Forging)?

A

Recrystallization is the process in which grains of a crystal structure come in a new structure or new crystal shape

Recrystallization is a process by which deformed grains are replaced by a new set of defect-free grains that nucleate and grow until the original grains have been entirely consumed.

33
Q

What are some Forging Machines?

A
  1. Presses
    o Hydraulic
    o Mechanical
    o Screw
  2. Hammers
    o Gravity drop
    o Power drop
    o Counterblow (two hammers)
    o High-energy-rate Machines
    (Pneumatic)
34
Q

Impact vs. press forging?

A
  • Forge hammer - applies an impact load
  • Forge press - applies gradual pressure
    -Slow continuous pressure
    -Pressure extends deep into the material
    -A greater proportion of energy transferred to the material
    -Better surface finish
35
Q

What are 3 types of Forging Processes?

A

1- Open-die forging
2- Impression-Die Forging
3- Flashless (closed die) Forging

36
Q

What is Open-die Forging?

A

Work is compressed between two flat dies, allowing metal to flow laterally with minimum constraint

37
Q

What is Impression-Die Forging?

A

Impression die forging presses metal between two dies that contain a precut profile of the desired part.
β–ͺ Flash is formed by metal that flows beyond the die cavity into a small gap between die plates
β–ͺ Flash must be later trimmed

Limitations:
➒ Not capable of close tolerances
➒ Machining is often required to achieve accuracies and features needed

38
Q

What is Flashless (Closed Die) Forging?

A

o Compression of work in punch and die tooling whose cavity does not allow for flash
o Starting work volume must equal die cavity volume within very close tolerance

39
Q

What are some Advantages and Limitations of impression-Die Forging?

A

Advantages of impression-die forging compared to machining from solid stock:
o Higher production rates
o Less waste of metal
o Greater strength

Limitations:
o Not capable of close tolerances (Β± 0.030”)
o Machining is often required to achieve accuracies and features needed

MENG 141 Manufacturing Processes 1 (12 decks)

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