In manufacturing, it is important to understand the relationship between product variety and product quantity. With an a

[answerhappygod]

In manufacturing, it is important to understand the relationship
between product variety and product quantity. With an aid of a
suitable diagram, describe this relationship when comparing typical
factories. [2]
2. Define the term “Lean Production”. [1]

3. What are the “building blocks” of modern manufacturing.
[1]
4. As a metallurgist working on a steel powder project, you are
requested to recommend a suitable shaping process to manufacture
parts. State the shaping process you would recommend, and support
your answer. [2] 5.
Processing operation transforms a work material from one state of
completion to a more advanced state that is closer to the final
desired product. With an aid of a simple illustration, classify the
different processing operations. [5]

6. Is it difficult to apply deformation processes on brittle metal
materials? Support your answer. [2]

7. Describe the major difference between the shaping processes and
the property enhancing processes. [2]

8. Casting is a process where a molten metal flows by gravity or
other force into a mold where it solidifies in the shape of the
mold cavity. Tabulate (as shown below) the benefits and limitations
associated with casting.
[4] BENEFITS LIMITATIONS 1. 1. 2. 2. 3. 3. 4. 4.

9. As a metallurgist working for company AA, which produces over
200 000 cast units per hour (i.e. high production), which type of
mold would you recommend using in order to meet the production
demands. Support your answer.
[2]
3
10. With an aid of a diagram, briefly but comprehensively describe
a cost effect pattern you would recommend to make a large circular
and symmetrical mold cavity. [5]

11. In casting operations i.e sand mold casting, a turbulent flow
of liquid metal needs to be eliminated and/or minimized. State the
challenges associated with the turbulent flow of molten metal into
the mold. [2]
12. Using suitable diagrams, show the differences between the grain
structure of a pure metal and the grain structure of a metal alloy.
[4]
13. How does the solidification of alloys differ from the
solidification of pure metals.
[2]
14. As a metallurgist working on a foundry, you are requested to
briefly but comprehensively discuss the shrinkage that is
experienced during a casting operation. This discussion must
include the following: [6] (i) Modes of shrinkage(s). (ii)
Shrinkage compensation. (iii) Factors influencing metal
shrinkage. 15. Using the Chvorinov’s Rule, show that the
molten metal with a mold constant of 4 mins/cm2 in a
cylinder-shaped mold will solidify faster than the same molten
metal in a sphere-shaped mold. [9] [answer to 2
decimal points] Note the following: i. both shapes have a
volume of 0.005 cubic meter ii. cylinder-shaped mold has a height
to diameter ratio = 1
16. A pure aluminum sphere with a diameter of 130 mm is to be cast
in an open mold casting operation. The melting temperature of
aluminum is 660 oC and while the pouring temperature is 800 oC.
Compute the amount of heat that must be added to the metal to heat
it to the pouring temperature, starting from a room temperature of
25°C. The heat of the fusion of aluminum is 389,3 J/g while the
density and specific heat is 2,70 g/cm3 and 0,21 Cal/g.oC,
respectively. (Note 1 cal = 4,168 J). Assume no heat losses and
that the specific heat for the solid and molten aluminum has the
same value. [4] [answer to 2 decimal points]
4
17. During a casting operation, it was observed that certain metal
alloy takes 20 minutes for a cube-shaped casting (cube volume =
3375 cm3) to solidify. If the same alloy and casting operation were
used, determine the total solidification time for a sphere-shaped
casting with a diameter of 200 mm. [Note: n = 2] [7]
[answer to 2 decimal points]

TOTAL MARKS = 60 MARKS
END TEST