Metal Casting Flashcards
Describe and categorize the distinguishing characteristics of common approaches to metal casting, including sand casting, investment casting, lost-foam casting, and die casting.
o Sand casting: the material of the mold is sand
o Investment casting: (lost wax) the pattern is made from wax, pattern is coated in a slurry of refractory materials, wax is melted out (can be recovered), metal is poured in, often done as multiple parts on a “tree”
o Lost-foam casting: a polystyrene pattern vaporizes when the molten metal is poured in, often small parts are cast together in a cluster
o Die casting: a permanent mold casting technique
Clearly identify if a metal casting process uses permanent or expendable mold, and permanent or expendable pattern
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Identify and explain the functional purpose of common components in casting mold design, such as sprues, runners, gates, risers, vents, cores, draft angle, and chills
o Sprues: passageways through which the metal flows downward
o Runners: channels which carry the molten metal from the sprue to the mold cav
o Gates: inlets into the mold cavity
o Risers: supplies additional molten metal
o Vents: used to allow the air in the mold
o Cores: used to form hollow regions or cavities
o Draft angle: the slight angle that allows the part to be ejected from the mold easier
o Chills: cooling channels inside the die, there are used to control or correct the cooling of the object
Name common casting metals & alloys, with quantitative estimate of melting temperature
o Zinc Alloys 390-530 ºC o Aluminum Alloys 480-660 o Magnesium Alloys 610-620 ºC o Copper Alloys (Brass, Bronze, etc.) 890-1260 ºC o Nickel Alloys 1110-1450 ºC o Steels & Irons 1370-1530 ºC o Titanium Alloys 1550-1650 ºC
Give examples of metal casting defects and explain their causes
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Compare relative merits of different metal casting methods in terms of criteria such as shape complexity, dimensional accuracy, surface finish, production rate, material diversity, and equipment requirements.
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Describe and distinguish processes for forming and shaping plastics, including extrusion, injection molding, blow molding, thermoforming, compression molding, and (polymer) casting
o Extrusion: o Injection molding: o Blow molding: o Thermoforming: o Compression molding: o (Polymer) Casting:
Postulate likely processes from which a plastic part may have been fabricated, based on characteristics and evidence in the part
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Compare relative merits of different processes for plastic fabrication, in terms of criteria such as shape complexity, production rate, material diversity, and equipment requirements
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