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Cork Institute of Technology
Higher Certificate in Engineering in Mechanical Engineering – Award
(National Certificate in Engineering in Mechanical Engineering - Award)
(NFQ – Level 6)
Summer 2005
Manufacturing Technology- Workshop /Materials
(Time: 3 Hours)
Instructions Answer FIVE questions. All questions carry equal marks. Question 1 must be answered. Use separate answer books for each Section. Use annotated diagrams where applicable. If you attempt Q2, please return the equilibrium diagram sheet with your answer book.
Examiners: Mr. M. Daly Mr. R. Kennedy Dr. G. Kelly Mr. R. Simpson Mr. J. Connelly
Section A
Q1.(a) Describe with the aid of a diagram how the plate shown at Fig.1 can be set on a face plate for machining the 30 mm diameter bore. Assume the hole has been marked out. (12 marks)
(b) Make a list of the operations needed to carry out the machining. (8 marks)
Section B
Q2. (a) Describe the solidification of a 30% Sn 70% Pb solution when it is cooled from a temperature of 330°C to 120°C with the aid of the attached equilibrium diagram. Identify the phases present and estimate their composition at the points d to h indicated on the Pb Sn diagram. (10 marks) (Note Please return the equilibrium diagram with your answer book) (b) Determine the variation in the composition of the (^) α and (^) β phases for Sn Pb solid solutions with overall compositions of 15% Sn 85% Pb, 50% Sn 50% Pb, 85% Sn 15% Pb at a temperature of 120°C. Comment on the result. (10 marks)
Q3. (a) Provide a simple definition of a composite material and give to examples of composite materials. (4 marks) (b) Composite materials can be classified according to the nature of their reinforcement. Identify two types of composite reinforcement and explain the essential differences between them and how they have an impact on the directionality in the properties of composites. (8 marks) (c) A uniaxial epoxy-glass fibre composite is reinforced with fibres in the longitudinal only. If the volume fraction of the fibre Vf = 0.6, firstly compute the volume fraction of the matrix or epoxy material Vm then estimate the elastic modulus of the composite in the longitudinal direction E (^) cl. Assume the elastic modulus of the matrix E (^) m = 4.0 Gpa, the elastic modulus of the fibre Ef = 70 Gpa. (8 marks)
Section B
Q2 Pb Sn Equilibrium diagram
Student Name Class
20 80 4060 6040 8020 100 %Sn 0 %Pb
0 100
100
200
300
100
200
300
Temperature
o^ C
327 oC
183 oC
231 oC
Composition
G H
PbSn Equilibrium Diagram
d e
f
g h
20 80 4060 6040 8020 100 %Sn 0 %Pb
0 100
100
200
300
100
200
300
Temperature
o^ C
327 oC
183 oC
231 oC
Composition
G H
PbSn Equilibrium Diagram
d e
f
g h
