EMAE 160 FINAL REVIEW CWRU
QUESTIONS WITH COMPLETE
ANSWERS
Name another term for investment casting and explain the origin. - ANSWER-Lost
wax casting. People used beeswax 1000's of years ago.
List metals that are typically die cast. - ANSWER-Aluminum & Magnesium
In terms of die casting, what is flash? - ANSWER-Extra material from between the
two plates.
What is the symbol for surface finish? What parameters may be included? -
ANSWER-√. Can include roughness height, waveness height, waveness width,
roughness width cutoff, and roughness width.
What are ribs and gussets? - ANSWER-Ribs- Square supports. Gussets- Triangular
supports.
What is the significance of draft on a part? - ANSWER-So that it can easily come out
of the mold.
How are internal features created in a sand casting? - ANSWER-A core supported
by chaplets.
What type of sand is most often used for sand casting? What type of sand is used for
core creation? - ANSWER-Green/silica sand. Cores are often made with green sand
mixed with core oil.
What material is used to create the pattern in shell molding? Why? - ANSWER-Iron
or steel. This is so it can heat up to stick to the resin and sand.
In die casting, what is the ejection system and how does it operate? - ANSWER-The
ejection system pops the part away from the mold so that it doesn't stick to the mold.
What materials may be used in hot chamber die casting? What about cold chamber?
- ANSWER-Hot Chamber- Zinc, Lead, Tin. Cold Chamber- Aluminum and
Magnesium.
What is the function of a sprue and riser? - ANSWER-Riser- Space for excess
molten metal to flow into. Sprue- The vertical passage for molten metal to enter the
mold.
What is the function of a runner and gate? - ANSWER-Runner- For molten metal to
reach the mold cavity. Gate- To ensure that molten metal enters the cavity at the
same rate as solidification.
, What are the differences between centrifugal casting and semi-Centrifugal casting? -
ANSWER-Centrifugal only wants metal to stick to the walls. Semi-Centrifugal wants
to evenly spread material through molds.
What is bend allowance? What sort of materials does it apply to? - ANSWER-Bend
allowance is the length a part gains when it is unbent. This is equal to the arc length
of the bend. This applies to all bent parts.
Name the three basic types of forging operations. - ANSWER-Open die, closed die,
impression die
Does the flash produced in impression die forging serve a useful purpose? Is it
desirable? Why? - ANSWER-Yes. This flash cools quicker than the part in the cavity
and thus keeps the rest of the metal fixed where it needs to be.
Define spring-back in sheet metal bending. - ANSWER-When a bent piece of sheet
metal bends back a bit after releasing the force that bend it in the first place.
What is a blind hole? What is undesirable about a blind hole? - ANSWER-A blind
hole is a hole that goes down a certain depth but not all the way through a part. It
has a pointed bottom and not a flat one.
What type of fastener is a counterbore and countersink for? - ANSWER-A
counterbore is for cylindrical head bolts and screws. A countersink is for conical
head bolts and screws.
What is a chamfer? - ANSWER-An angled cutoff of an edge.
What are burrs? - ANSWER-Small pieces that remain attached to a material after
machining.
What materials are cutting tools commonly made from? - ANSWER-Carbide, steel,
non-ferrous cast alloys, ceramics, and sintered oxides.
Explain how a match plate is used in sand casting and why it is advantageous. -
ANSWER-It is used to line up the two halves of the mold. You can bolt through holes
in the match plate.
Explain the term parting line when referencing the die casting process. - ANSWER-
Some metal that leaks out of the mold between the two match plates.
The "lost foam" of full-mold process requires what type of pattern? - ANSWER-
Evaporative pattern
What is the shell molding process? - ANSWER-A casting process using metal
masters and a resin to bind the molding sand.
What is the parting line in injection molding? - ANSWER-The joint between the two
mold halves.
QUESTIONS WITH COMPLETE
ANSWERS
Name another term for investment casting and explain the origin. - ANSWER-Lost
wax casting. People used beeswax 1000's of years ago.
List metals that are typically die cast. - ANSWER-Aluminum & Magnesium
In terms of die casting, what is flash? - ANSWER-Extra material from between the
two plates.
What is the symbol for surface finish? What parameters may be included? -
ANSWER-√. Can include roughness height, waveness height, waveness width,
roughness width cutoff, and roughness width.
What are ribs and gussets? - ANSWER-Ribs- Square supports. Gussets- Triangular
supports.
What is the significance of draft on a part? - ANSWER-So that it can easily come out
of the mold.
How are internal features created in a sand casting? - ANSWER-A core supported
by chaplets.
What type of sand is most often used for sand casting? What type of sand is used for
core creation? - ANSWER-Green/silica sand. Cores are often made with green sand
mixed with core oil.
What material is used to create the pattern in shell molding? Why? - ANSWER-Iron
or steel. This is so it can heat up to stick to the resin and sand.
In die casting, what is the ejection system and how does it operate? - ANSWER-The
ejection system pops the part away from the mold so that it doesn't stick to the mold.
What materials may be used in hot chamber die casting? What about cold chamber?
- ANSWER-Hot Chamber- Zinc, Lead, Tin. Cold Chamber- Aluminum and
Magnesium.
What is the function of a sprue and riser? - ANSWER-Riser- Space for excess
molten metal to flow into. Sprue- The vertical passage for molten metal to enter the
mold.
What is the function of a runner and gate? - ANSWER-Runner- For molten metal to
reach the mold cavity. Gate- To ensure that molten metal enters the cavity at the
same rate as solidification.
, What are the differences between centrifugal casting and semi-Centrifugal casting? -
ANSWER-Centrifugal only wants metal to stick to the walls. Semi-Centrifugal wants
to evenly spread material through molds.
What is bend allowance? What sort of materials does it apply to? - ANSWER-Bend
allowance is the length a part gains when it is unbent. This is equal to the arc length
of the bend. This applies to all bent parts.
Name the three basic types of forging operations. - ANSWER-Open die, closed die,
impression die
Does the flash produced in impression die forging serve a useful purpose? Is it
desirable? Why? - ANSWER-Yes. This flash cools quicker than the part in the cavity
and thus keeps the rest of the metal fixed where it needs to be.
Define spring-back in sheet metal bending. - ANSWER-When a bent piece of sheet
metal bends back a bit after releasing the force that bend it in the first place.
What is a blind hole? What is undesirable about a blind hole? - ANSWER-A blind
hole is a hole that goes down a certain depth but not all the way through a part. It
has a pointed bottom and not a flat one.
What type of fastener is a counterbore and countersink for? - ANSWER-A
counterbore is for cylindrical head bolts and screws. A countersink is for conical
head bolts and screws.
What is a chamfer? - ANSWER-An angled cutoff of an edge.
What are burrs? - ANSWER-Small pieces that remain attached to a material after
machining.
What materials are cutting tools commonly made from? - ANSWER-Carbide, steel,
non-ferrous cast alloys, ceramics, and sintered oxides.
Explain how a match plate is used in sand casting and why it is advantageous. -
ANSWER-It is used to line up the two halves of the mold. You can bolt through holes
in the match plate.
Explain the term parting line when referencing the die casting process. - ANSWER-
Some metal that leaks out of the mold between the two match plates.
The "lost foam" of full-mold process requires what type of pattern? - ANSWER-
Evaporative pattern
What is the shell molding process? - ANSWER-A casting process using metal
masters and a resin to bind the molding sand.
What is the parting line in injection molding? - ANSWER-The joint between the two
mold halves.
