UNIVERSITY OF MAURITIUSFACULTY OF ENGINEERING

MECHANICAL & PRODUCTION ENGINEERING DEPARTMENT.Manufacturing Processes & Metrology - MECH 3002Y

Class Test - Semester 2 (Academic Year 2014-2015)

Answer ALL Questions (Total marks = 40) Time = 50 mins

1. An engineer is designing a method to forge a 0.3 % solid carbon steel cylindrical rod (Dimensions:25 mm diameter and 150 mm length) into a solid'T' shape structure. The T shape structure will havethe dimensions as shown in Figure 1. All dimensions are in millimeters.

Explain in details, and by using any appropriate calculation(s) how the engineer will proceed toobtain the forged 'T shape structure. The answer should include the justification(s) of the chosenprocess, and the main steps of the procedure for the actual operation, and any assumptions (Note: (j)represents diameter).

[10 marks]

= 75 1)2 = 25

Figure 1: 'T' shape forged part with all dimensions in mm.

2. A bronze bushing of internal diameter 450 mm has been manufactured by the sand casting process.Explain with justifications the most appropriate non-destructive technique (NDT) which can be usedto detect both the presence of surface cracks and sub-surface micro-cracks on the bronze bushing.

[10 marks]

3. (i). Explain the phenomenon of fretting, and provide a practical example of its occurrence in anindustrial context. [6 marks']

(ii). Outline two (2) methods which can be used to reduce Fretting problems.[4 marks]

4. A casting manufacturing company has been awarded a contract to produce (to net shape) 1500high strength bronze gear of 150 mm PCD and 4.5 mm thickness per week. The company operatessix (6) days per week (with one shift of eight effective production hours per day during weekdays,and on Saturdays, one shift of 6 effective production hours). Each gear weighs about 750 grammes.

Select and explain the most appropriate casting process which can be used to produce the bronzegear. Justify the answer, and outline the salient features of the selected process.

[10 marks]

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