Download MECH7007 Manufacturing Tech Exam 2009/10: B.Eng (Hons) Mech Eng and more Exams Manufacturing Technologies in PDF only on Docsity!
CORK INSTITUTE OF TECHNOLOGY
INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ
Semester 1 Examinations 2009/
Module Title: Manufacturing Technology
Module Code: MECH
School: Mechanical & Process Engineering
Programme Title: Bachelor of Engineering (Honours) Mechanical Engineering Bachelor of Engineering Mechanical Engineering
Programme Code: EMECH_8_Y2 / EMECH_7_Y
External Examiner(s): Mr. John J. Hayes, Prof. Robin Clarke
Internal Examiner(s): Mr Matt Cotterell
Instructions: Answer FOUR Questions.
Duration: 2 hrs
Sitting: Winter 2009
Requirements for this examination:
Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator.
Q
An orthogonal cutting test yielded the following data:
Cutting Force Fc = 625 N Feed Force Ff = 524 N Uncut chip thickness h = 0.10 mm Chip thickness h c = 0.26 mm
Tool rake angle γne = 10˚
Width of cut w = 4 mm
From this data, construct Merchants circle and determine:
(i) Shear angle φ (5 Marks)
(ii) Shear plane force components: Fs and Fn (5 Marks)
(iii) Apparent shear strength of the material τs (5 Marks)
(iv) Rake face force components: F and N (5 Marks)
(v) Coefficient of friction on the rake face μ and
friction angle β (5 Marks)
Q
(i) Discuss the mechanisms that contribute to tool wear and how they are influenced by cutting sped; distinguish between continuous and interrupted cutting. (10 Marks)
(ii) Explain the basis for the Taylor Tool Life Equation vcT n^ = c (5 Marks)
where v (^) c = Cutting Speed (m/min) T = Tool Life (min) n = Tool Life exponent c = Constant
(iii) In a cutting test a cutting speed of 100 m/min yielded a tool life of 26 min. while a cutting speed of 60 m/min resulted in a tool life of 70 min. Determine the constants in the Taylor tool life and hence predict the tool life corresponding to a cutting speed of 150m/min. (10 Marks)
Q
(i) Sheet metal can be shaped through shearing, bending and deep drawing operations. Discuss the salient features of these processes and typical features/products that can be produced. (10 Marks)
(ii) A 25 mm diameter hole is to be punched in a 4 mm thick brass sheet. The ultimate shear strength of the work material is 320 N/mm^2 and cutting is complete at 50 % punch penetration. The recommended die clearance is 10 %. Determine suitable diameters for the punch and die, the maximum load on the punch and the total work done in the process. (15 Marks)
Fig. 3 (iii)
