Question 1. The component shown in FIGURE1 is to be produced in batches of 1000.
(a) State three major classifications of castings by which the component could be produced.
(b) Explain how each of these methods will affect the properties of the components produced (consider material and non-material properties, e.g. cost)
(c) Which of the methods you have stated in (a) would you recommend? Give reasons for your answer.
FIG. 1
Question 2. The component shown in FIGURE 2 is to be coated for protection against corrosion.
(a) State three methods by which this can be done.
(b) Discuss the suitability of each of the methods mentioned.
(c) Which of the methods mentioned in (a) would you recommend?
Give reasons for your answer.
FIG. 2
Question 3. (a) In the shaping process of powder produced materials, the size of the particles is an important characteristic. Name two other characteristics of particles which are of significance and describe how these characteristics affect the material.
(b) What factors determine particle size in metal powder production by chemical reaction?
(c) One method of determining particle sizes is to measure the velocity of descent when the particles are suspended in a fluid.
(i) Describe two other methods.
(ii) An experiment to determine ceramic particle sizes showed that the rate of descent when suspended in a fluid ranged from 1.2 × 10-6 m s-1 to 5 × 10-6 m s-1.
The density of the material was 3800 kg m-3 and the density and viscosity of the fluid at room temperature were 1632 kg m-3 and 0.00972 Pas respectively. Calculate the range of sizes of the particles.
Question 4. Discuss the roles of fillers, plasticisers and stabilisers in polymer processing.
Question 5. A sphere 100 mm diameter is to be coated with chromium from a solution containing chromium in the six valent (hexavalent) state. How much time would be needed to produce a coating 20 µm thick if :
• the current is 20 A
• the cathodic efficiency is 15%
• the atomic weight and density of chromium are 52 and 7.2 gcm-3 respectively