Quiz: Mechanical Engineering
Each question carries 2 mark
Negative marking: 1/3 mark
Time: 10 Minutes
Q1. Due to shake allowance:
(a) The fillets are provided on pattern
(b) The pattern is made slightly bigger than required size
(c) The taper is provided on vertical faces of pattern
(d) The pattern is made slightly smaller than required size
Q2. Which of the following is not casting defect?
(a) Hot tears
Q3. Which of the following statements are correct about casting defects?
1. Drop and Dirt is a moulding material defect.
2. Buckle is a gas defect.
3. Swell is a moulding material defect.
4. Misrun is a pouring material defect.
(a) 1, 2 and 3
(b) 2, 3 and 4
(c) 1, 3 and 4
(d) 1, 2, 3 and 4
Q4. Sieve shaker test is done to find
(a) Permeability number
(b) Mould hardness number
(c) Grain fineness number
(d) Mould strength
Q5. Match plate patterns is used to
(a) Produce small size objects in mass production
(b) Produce small size complex objects in mass production
(c) Produce three-dimensional complex large mould cavities
(d) Support structurally weak member of a pattern
Q6. Solidification time of a casting will be more if
(a) thermal conductivity of moulding sand is less
(b) thermal diffusivity of moulding sand is more
(c) the pouring temperature of molten metal is low
(d) if specific heat of molten metal and sand are low
Q7. Which of the following are produced by slush casting?
(a) Hollow casting with thick walls
(b) Hollow casting with thin walls
(c) Thin castings
(d) Thick castings
Q8. Consider the following characteristics:
1. High pressure are required
2. Used for making castings of aluminium
3. Melting unit as integral part.
Which of these characteristics of cold chamber die casting process are correct?
(a) 1, 2 and 3
(b) 1 and 2 only
(c) 1 and 3 only
(d) 2 and 3 only
Q9. The mould in shell moulding process is made uo of which of the following?
(a) Gypsum + Setting agents
(b) Green sand + Clay
(c) Sodium silicate + Dried sand
(d) Dried silica + Phenolic resins
Q10. Which of the following casting methods utilizes wax pattern?
(a) Die casting
(b) Centrifugal casting
(c) Investment casting
(d) Semi-centrifugal casting
Sol. Shake allowance is provided on the pattern because pattern is taken out from the mould
while moving pattern to and fro. This causes the mould cavity to become larger than required
size, hence pattern has to be made slightly smaller than required size.
Sol. Hot tears, Run-out and blow holes are all casting defects that are produced due to
poor collapsibility of sand mold, leak out of the metal from faulty casting mold and gas
entrapment in the casting mold respectively.
Sol. Buckle is a shallow, broad, vee depression that occurs in the surface of flat casting. It occurs due to sand expansion caused by heat of metal and is a moulding material defect.
Sol. Sieve shaker test is performed to define grain fineness number of moulding sands, which shows average distribution of grain size.
Sol. Match plate patterns are used to produce small size complex objects and gated patterns are used to produce small size objects of simple shapes.
Sol. Solidification time of a casting will be more if thermal conductivity of moulding sand is less.
Sol. Hollow castings with thin walls are produced by slush casting.
Slush casting is suitable for small production runs and is generally used for making ornamental and decorative objects and toys from low-melting point metals such as lead, tin etc.
Sol. The main difference between cold-chamber die-casting and hot-chamber die casting manufacture is that in the cold chamber process the molten metal for the casting is introduced to the casting chamber from an external source, while in the hot chamber process the source of molten metal is attached to the machine itself.
Sol. In shell moulding the mould is made up of mixture of dried silica and phenolic resin, formed into a thin half-mould shells which are clamped together for pouring metal.
Sol. In investment casting, pattern is made up of molten wax or plastics.