EMAE 160 MIDTERM EXAM
QUESTIONS WITH VERIFIED
ANSWERS.
What is bend allowance? What sort of materials does it apply to? - ANSWER-Bend
allowance refers to the arc length of a bend in a part. It represents material that
needs to be added to the length of the unbent part in order to have the correct
dimensions on the finished part. It applies to tubes, sheets, and plates.
Name the three basic types of forging operations. - ANSWER-- Open-die forging
- Impression die forging
- Closed-die forging (flashless)
Does the flash produced in impression die forging serve a useful purpose? Is it
desirable? Why? - ANSWER-The flash spreads out in a thin layer around the forging
cavity, solidifying quickly because of its thinness. Once it's solidified, it keeps the
remaining metal trapped inside the die.
Define spring-back in sheet metal bending. - ANSWER-Spring back is the tendency
of metal to pull back towards its original shape after bending force is removed. To
combat this behavior, bent parts are usually slightly over-bent, so they spring back
into the desired shape.
Name the three types of forging presses. - ANSWER-- Hydraulic
- Mechanical
- Impact
Explain the difference between a mechanical press and a hydraulic press for forging.
- ANSWER-A mechanical press applies short, powerful bursts of pressure, whereas
a hydraulic press applies a steady pressure.
Explain the differences between cold-rolled and hot-rolled steels. - ANSWER-Cold
rolled steel have better tolerances and surface finishes, as well as better mechanical
properties, but require much higher forces to make. Hot rolling is faster and cheaper,
but requires heating the material.
Is forging always done in a vertical direction? - ANSWER-No.
How is a soda can made? - ANSWER-Deep drawing.
What are the differences between deep drawing and impact extrusion? - ANSWER-
Impact extrusion pushes material through a die to make a solid part, while deep
drawing pushes a punch into the material, forming the material around the punch
and creating a hollow part.
How is high pressure tubing made? - ANSWER-Extrusion.
, How is low pressure pipe made? - ANSWER-Bending and welding, with some
exterior surface finishing.
What is the most common metal used in extrusion? - ANSWER-Aluminum.
How are the undercarriage tubes in the automotive industry created? - ANSWER-
Hydroforming.
House gutters are manufactured using what process? - ANSWER-Roll forming.
What is metal spinning? - ANSWER-Metal spinning is a process by which a radially
symmetrical piece of stock is spun about its axis of symmetry and material is
removed to create a part that is also radially symmetrical.
In casting, what is a flask? - ANSWER-A type of tooling used to contain the two
halves of the mold. It consists of two parts and forms a frame around the mold.
In sand casting, how does the volumetric size of the pattern compare to the finished
cast part? - ANSWER-The pattern is slightly larger than the finished part.
Describe shell molding. - ANSWER-It is a mold casting process that uses a resin
covered sand to form the mold.
Name another term for investment casting and explain the origin. - ANSWER-Lost
wax casting. It is thousands of years old and originally use beeswax and sand.
List those metals that are typically die cast. - ANSWER-- Aluminum
- Magnesium
- Zinc
- Lead
- Tin
- Copper
In terms of die casting, what is flash? - ANSWER-Excess material that leaks out of
the cast cavity and solidifies in a thin, flat layer sticking out around the part.
What is the symbol for surface finish, and what parameters may be included? -
ANSWER-A check mark with the base on the surface. Waviness and roughness may
both be specified.
What are ribs and gussets? - ANSWER-Thin pieces of material that connect to two
pieces and hold them in place.
What is the significance of draft on a cast part? - ANSWER-Draft is important
because it allows the part to be easily removed from the mold. When the part is
pulled out, it separates from the mold at all point.
QUESTIONS WITH VERIFIED
ANSWERS.
What is bend allowance? What sort of materials does it apply to? - ANSWER-Bend
allowance refers to the arc length of a bend in a part. It represents material that
needs to be added to the length of the unbent part in order to have the correct
dimensions on the finished part. It applies to tubes, sheets, and plates.
Name the three basic types of forging operations. - ANSWER-- Open-die forging
- Impression die forging
- Closed-die forging (flashless)
Does the flash produced in impression die forging serve a useful purpose? Is it
desirable? Why? - ANSWER-The flash spreads out in a thin layer around the forging
cavity, solidifying quickly because of its thinness. Once it's solidified, it keeps the
remaining metal trapped inside the die.
Define spring-back in sheet metal bending. - ANSWER-Spring back is the tendency
of metal to pull back towards its original shape after bending force is removed. To
combat this behavior, bent parts are usually slightly over-bent, so they spring back
into the desired shape.
Name the three types of forging presses. - ANSWER-- Hydraulic
- Mechanical
- Impact
Explain the difference between a mechanical press and a hydraulic press for forging.
- ANSWER-A mechanical press applies short, powerful bursts of pressure, whereas
a hydraulic press applies a steady pressure.
Explain the differences between cold-rolled and hot-rolled steels. - ANSWER-Cold
rolled steel have better tolerances and surface finishes, as well as better mechanical
properties, but require much higher forces to make. Hot rolling is faster and cheaper,
but requires heating the material.
Is forging always done in a vertical direction? - ANSWER-No.
How is a soda can made? - ANSWER-Deep drawing.
What are the differences between deep drawing and impact extrusion? - ANSWER-
Impact extrusion pushes material through a die to make a solid part, while deep
drawing pushes a punch into the material, forming the material around the punch
and creating a hollow part.
How is high pressure tubing made? - ANSWER-Extrusion.
, How is low pressure pipe made? - ANSWER-Bending and welding, with some
exterior surface finishing.
What is the most common metal used in extrusion? - ANSWER-Aluminum.
How are the undercarriage tubes in the automotive industry created? - ANSWER-
Hydroforming.
House gutters are manufactured using what process? - ANSWER-Roll forming.
What is metal spinning? - ANSWER-Metal spinning is a process by which a radially
symmetrical piece of stock is spun about its axis of symmetry and material is
removed to create a part that is also radially symmetrical.
In casting, what is a flask? - ANSWER-A type of tooling used to contain the two
halves of the mold. It consists of two parts and forms a frame around the mold.
In sand casting, how does the volumetric size of the pattern compare to the finished
cast part? - ANSWER-The pattern is slightly larger than the finished part.
Describe shell molding. - ANSWER-It is a mold casting process that uses a resin
covered sand to form the mold.
Name another term for investment casting and explain the origin. - ANSWER-Lost
wax casting. It is thousands of years old and originally use beeswax and sand.
List those metals that are typically die cast. - ANSWER-- Aluminum
- Magnesium
- Zinc
- Lead
- Tin
- Copper
In terms of die casting, what is flash? - ANSWER-Excess material that leaks out of
the cast cavity and solidifies in a thin, flat layer sticking out around the part.
What is the symbol for surface finish, and what parameters may be included? -
ANSWER-A check mark with the base on the surface. Waviness and roughness may
both be specified.
What are ribs and gussets? - ANSWER-Thin pieces of material that connect to two
pieces and hold them in place.
What is the significance of draft on a cast part? - ANSWER-Draft is important
because it allows the part to be easily removed from the mold. When the part is
pulled out, it separates from the mold at all point.
