Test 2.1
A riser in casting is described by which of the following (three correct answers):
metal that is not part of the casting, source of molten metal to feed the casting and compensate for shrinkage during solidification, and waste metal that is usually recycled? [Chapter 5]
Which of the following stress or strength parameters is used in the computation of rolling force (one best answer):
average flow stress [Chapter 13]
Which of the following stress or strength parameters is used in the computation of the force in an extrusion operation (one best answer):
average flow stress [Chapter 13]
Which of the following are alternative names for indirect extrusion (two correct answers):
backward extrusion and everse extrusion [Chapter 13]
Which of the following bulk deformation processes are involved in the production of nails for lumber construction (three best answers):
bar and wire drawing, flashless forging, and impression die forging [Chapter 13]
Which of the following are advantages of die casting over sand casting (four best answers):
better surface finish, closer tolerances, higher production rates, and mold can be reused [Chapter 6]
The term encapsulation refers to which one of the following plastics shaping processes:
casting [Chapter 7]
Shell molding is best described by which one of the following:
casting process in which the mold is a thin shell of sand bonded by a thermosetting resin [Chapter 6]
Which of the following casting processes are permanent mold operations (three correct answers):
centrifugal casting, die casting, and basic casting [Chapter 6]
In foundry work, a runner is which one of the following:
channel in the mold leading from the downsprue to the main mold cavity, [Chapter 5]
The principal components of an injection molding machine are which two of the following:
clamping unit, injection unit [Chapter 7]
True or False: The press-and-blow process is best suited to the production of (narrow-necked) beverage bottles, while the blow-and-blow process is more appropriate for producing (wide-mouthed) jars:
False, it's the reverse [Chapter 7]
True or False: The particle size that can pass through a screen is obtained by taking the reciprocal of the mesh count of the screen:
False: The given description neglects consideration of the screen wire thickness [Chapter 10]
Which of the following processes would be applicable to produce hulls for small boats (three best answers):
blow molding, rotational molding, and vacuum thermoforming [Chapter 7]
In casting, a flask is which one of the following:
box which holds the cope and drag [Chapter 5]
The upper half of a sand-casting mold is called which of the following:
cope [Chapter 5]
Sand casting is which of the following types:
expendable mold [Chapter 5]
Which of the following qualifies as a precision-casting process (two correct answers):
investment casting, plaster-mold casting [Chapter 6]
Which of the following casting processes are expendable mold operations (four correct answers):
investment casting, sand casting, shell molding,vacuum molding [Chapter 6]
Investment casting is also known by which one of the following names:
lost-wax process [Chapter 6]
Casting is a glassworking process used for
low production [Chapter 7]
Which of the following is typical of the starting work geometry in sheet metal processes
low volume-to-area ratio [Chapter 12]
The coefficient of friction between the part and the tool in cold working tends to be
lower [Chapter 12]
For which one of the following reasons is a green mold named:
moisture is contained in the mold [Chapter 6]
Cupolas are furnaces used to melt which of the following metals
cast iron [Chapter 6]
True or False: The forward movement of polymer melt in an extruder barrel is resisted by drag flow, which is caused by the resistance to flow through the die orifice:
False: Drag flow is the forward motion of the melt caused by the Archimedian screw principle in the barrel. The resistance to forward flow is called back pressure flow. [Chapter 8]
True or False: Flash in impression die forging serves no useful purpose and is undesirable because it must be trimmed from the part after forming:
False: Flash causes build-up of pressure inside the die, which forces the work metal to fill the die cavity. [Chapter 13]
A lehr is which of the following:
an annealing furnace [Chapter 7]
In cold isostatic pressing, the mold is most typically made of which one of the following:
rubber [Chapter 10]
The function of the ejection system is which one of the following:
separate the part from the cavity after molding [Chapter 7]
The starting workpiece in steel hot rolling of plate and sheet stock is which of the following (one best answer):
slab [Chapter 13]
Which of the following rolling mill types are associated with relatively small diameter rolls in contact with the work (two correct answers):
cluster mill & four-high mill [Chapter 13]
Which of the following operations are closely related to open-die forging (three best answers):
cogging, fullering, and upsetting [Chapter 13]
Which of the following are classified as forging operations (four correct answers):
coining, fullering, swaging, and upsetting [Chapter 13]
Which of the following are sections of a conventional extruder barrel for thermoplastics (three best answers):
compression section, feed section, & metering section [Chapter 7]
Which of the following are advantages and characteristics of hot working relative to cold working (four correct answers):
fracture of workpart is less likely, isotropic mechanical properties, lower deformation forces is required, and more significant shape changes are possible [Chapter 12]
In a sand-casting mold, the V/A ratio of the riser should be ________than the V/A ratio of the casting itself?
greater than, [Chapter 5]
In which of the following properties do plastic parts often compare favorably with metals (two best answers):
impact resistance & strength-to-weight ratio [Chapter 7]
Increasing strain rate tends to have which one of the following effects on flow stress during hot forming of metal
increases flow stress [Chapter 12]
Turbulence during pouring of the molten metal is undesirable for which of the following reasons (two best answers):
it increases erosion of the mold surfaces & it increases the formation of metallic oxides that can become entrapped during solidification, [Chapter 5]
The flow curve expresses the behavior of a metal in which of the following regions of the stress-strain curve:
plastic region [Chapter 12]
The two most common polymer foams are which of the following:
polystyrene & polyurethane [Chapter 7]
Which of the following statements is correct in the context of metallic powders (three correct answers):
porosity + packing factor = 1.0, packing factor = 1.0 - porosity, and packing factor = bulk density/true density [Chapter 10]
Which one of the following casting processes is the most widely used:
sand casting [Chapter 6]
Which one of the following processes or processing steps is not applicable in glassworking:
sintering, Sintering is used to cause bonding of particulate materials such as metal and ceramic powders. [Chapter 7]
For a given weight of metallic powders, the total surface area of the powders is increased by which of the following (two best answers):
smaller particle size and higher shape factor [Chapter 10]
Which of the following powder shapes would tend to have the lowest interparticle friction:
spherical [Chapter 10]
The charge in glassworking is which one of the following:
the starting materials in melting? [Chapter 7]
Total solidification time is defined as which one of the following:
time between pouring and complete solidification, [Chapter 5]
Given that Wm = weight of the molten metal displaced by a core and Wc = weight of the core, the buoyancy force is which one of the following:
upward force = Wm - Wc [Chapter 6]
Which one of the following terms refers to the glassy state of a material:
vitreous [Chapter 7]
The parting line in injection molding is which one of the following:
where the two mold halves come together [Chapter 7]
Repressing refers to a pressworking operation used to compress a sintered part in a closed die to achieve closer sizing and better surface finish:
True [Chapter 10]
A thermoforming mold with a convex form is called which one of the following
a positive mold [Chapter 7]
Use of a parison is associated with which one of the following plastic shaping processes
blow molding [Chapter 7]
Which of the following processes are generally limited to thermoplastic polymers (two best answers):
blow molding and thermoforming [Chapter 7]
Besides helping to preserve the environment, the use of recycled glass as an ingredient of the starting material in glassmaking serves what other useful purpose
makes the glass easier to melt [Chapter 7]
True or False: The production of tubing is possible in indirect extrusion but not in direct extrusion:
False, Tube and pipe cross sections can be produced by either direct or indirect extrusion [Chapter 13]
True or False: In rotational molding, centrifugal force is used to force the polymer melt against the surfaces of the mold cavity where solidification occurs:
False: It is the force of gravity in the doubly rotating mold that forces the polymer against the mold surfaces [Chapter 7]
In which of the following extrusion operations is friction a factor in determining the extrusion force (one best answer):
direct extrusion [Chapter 13]
Johnson's formula is associated with which one of the four bulk deformation processes:
extrusion [Chapter 13]
Which of the following are bulk deformation processes (three correct answers):
extrusion, forging,& rolling [Chapter 12]
Production of pipes and tubes is associated with which of the following bulk deformation processes (three correct answers):
extrusion, roll piercing, and tube sinking [Chapter 13]
Which of the following stress or strength parameters is used in the computation of the maximum force in a forging operation (one best answer):
final flow stress [Chapter 13]
Which of the following defects or problems is associated with injection molding (three correct answers):
flash, short shorts, and sink marks [Chapter 7]
Which of the following processes combines pressing and sintering of the metal powders (three best answers):
hot isostatic pressing, hot pressing, and spark sintering [Chapter 10]
A misrun is which one of the following defects in casting:
metal solidifies before filling the cavity [Chapter 6]
Which of the following design features would be difficult or impossible to achieve by conventional pressing and sintering (three best answers):
outside rounded corners, side holes, threaded holes [Chapter 10]
Impregnation refers to which of the following (two best answers):
putting polymers into the pores of a PM part & soaking oil by capillary action into the pores of a PM part [Chapter 10]
Chvorinov's rule states that total solidification time is proportional to which one of the following quantities: where A = surface area of casting, Hf = heat of fusion, Tm = melting temperature, and V = volume of casting?
(V/A)2 [Chapter 5]
Which of the following riser types are completely enclosed within the sand mold and connected to the main cavity by a channel to feed the molten metal (two correct answers):
Blind riser and side riser [Chapter 5]
In plaster mold casting, the mold is made of which one of the following materials:
CaSO4-H2O [Chapter 6]
Which one of the following processes is used to produce glass tubing:
Danner process [Chapter 7]
Which of the following metals would typically be used in die casting (three best answers):
aluminum, tin, and zinc [Chapter 6]
In sand casting, the volumetric size of the pattern is _________ than the cast part?
bigger than [Chapter 6]
As particle size increases, interparticle friction
decreases [Chapter 10]
If a glass part with a wall thickness of 5 mm (0.20 in) takes 10 minutes to anneal, how much time would a glass part of similar geometry but with a wall thickness of 7.5 mm (0.30 in) take to anneal (choose the one closest answer):
20 minutes, The rule is that annealing time varies as the square of the wall thickness. That would indicate an annealing time of (0.30/0.20)2 = 2.25 times 10 minutes or 22.5 minutes. 20 minutes is closest [Chapter 7]
Theoretically, the maximum reduction possible in a wire drawing operation, under the assumptions of a perfectly plastic metal, no friction, and no redundant work, is which of the following (one answer):
0.63 [Chapter 13]
Hot working of metals refers to which one of the following temperature regions relative to the melting point of the given metal on an absolute temperature scale:
0.6Tm [Chapter 12]
Which of the following most closely typifies the sintering temperatures in PM?
0.8 Tm, [Chapter 10]
The average flow stress is the flow stress multiplied by which of the following factors:
1/(1+n) [Chapter 12]
Typical glass melting temperatures are in which of the following ranges:
1500°C to 1600°C [Chapter 7]
Silica sand has which one of the following compositions:
SiO2 [Chapter 6]
A three-plate mold offers which of the following advantages when compared to a two-plate mold (two best answers):
automatic separation of parts from runners & gating is usually at the base of the part to reduce weld lines [Chapter 7]
Which of the following processes are associated with the production of plastic sheet and film (three correct answers):
blown-film extrusion process, calendering, & chill-roll extrusion [Chapter 7]
Which one of the following casting metals is most important commercially:
cast iron [Chapter 6]
The maximum possible draft in a rolling operation depends on which of the following parameters (two correct answers):
coefficient of friction between roll and work & roll diameter [Chapter 13]