Cork Institute of Technology
Bachelor of Engineering (Honours) in Mechanical Engineering – Stage 2
(Bachelor of Engineering in Mechanical Engineering - Stage 2)
(NFQ – Level 8)
Summer 2005
Manufacturing Engineering
(Time: 3 Hours)
Answer Five Questions Examiners: Prof. J. Monaghan
Attempt Two Questions from Section A, Mr. J. E. Hegarty
Two Questions from Section B, and Mr. M. Cotterell
One Question from Section C. Mr. J. Twohig
Use separate answer book for Section C.
Section A
Q.1 An orthogonal cutting test on titanium Ti6Al4V yielded the following data:
Cutting Force Fc = 486 N
Thrust Force Ft = 226 N
Uncut chip thickness to = 0.150 mm
Chip thickness tc = 0.138 mm
Cutting Speed vc = 120 m/min
Tool Rake Angle γ = 6.5˚
Width of cut b = 2.20 mm
From this data, construct Merchant’s circle of forces and the velocity triangle for the
process, and hence determine graphically or by calculation:
(i) Shear angle φ and the shear plane force components, Fs and Fn
(ii) Apparent shear strength of the material τs
(iii) Rake face force components, F and N and the coefficient of friction on the rake
face µ
(iv) Total power consumed in cutting and the relative proportions consumed in
shearing the material and in overcoming friction.
(20 marks)
