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Emg 2202: Workshop Processes &Amp; Practice Ii Question Paper
Emg 2202: Workshop Processes &Amp; Practice Ii
Course:Bachelor Of Science In Mechanical Engineering
Institution: Dedan Kimathi University Of Technology question papers
Exam Year:2011
KIMATHI UNIVERSITY COLLEGE OF TECHNOLOGY
UNIVERSITY SUPPLEMENTARY/SPECIAL EXAMINATIONS 2010/2011
SECOND YEAR FIRST SEMESTER SUPPLEMENTARY/ SPECIAL EXAMINATION
FOR THE DEGREE OF BACHELOR OF SCIENCE IN MECHANICAL
ENGINEERING
EMG 2202: WORKSHOP PROCESSES & PRACTICE II
DATE: 24 MARCH 2011 TIME: 8.30 AM – 10.30 AM
INSTRUCTIONS
i. This examination contains five questions.
ii. All questions carry equal marks.
iii. Answer any THREE questions.
iv. All symbols have usual meaning unless otherwise stated.
QUESTION ONE [20 Marks]
(a) What are the major differences between the 3-jaw chuck and the 4-jaw chuck?
[2 Marks]
(b) With the aid of well labeled sketches explain how the following processes are carried out
using a center lathe.
i. Undercutting [3 marks]
ii. Knurling [3 marks]
iii. Threading [4 marks]
iv. Step turning [4 Marks]
v. Boring [4 Marks]
QUESTION TWO [20 Marks]
(a) With the aid of well labeled diagrams, briefly explain chip formation process.
[6 Marks]
b) With the aid of diagrams, explain the three types of chips common in metal cutting
processes. [6 Marks]
c) State five differences between a capstan and a turret lathe. [5 Marks]
d) State any six conditions that affect metal cutting. [3 Marks]
QUESTION THREE [20 Marks]
(a) Give any five differences between oblique and orthogonal cutting. [5 Marks]
(b) Describe any four characteristics that a cutting tool must have in order to produce good
quality and economical parts. [4 Marks]
(c) With the aid of a well labeled diagram, illustrate how crater wear and flank wear occur in
a cutting tool. State any two causes of tool wear.
[3 Marks]
(d)
(i) Define tool life. [1 Mark]
(ii) A cylindrical workpiece is to be turned on a center lathe to a final diameter,
df =20mm. The selected spindle speed is N=1500 RPM. If the combination of
the material being turned and the cutting tool have an exponent of n=0.2 and a
constant of C=12.805, determine the tool life of the cutting tool.
[4 Marks]
(e) State any three advantages of a CNC lathe. [3 Marks]
QUESTION FOUR [20 Marks]
(a) With the aid of a neatly labeled diagram, describe at least six surfaces that can be produced on a
shaping machine. [3 Marks]
(b) Give six main parts of a shaping machine, giving the construction features and functions.
[6 Marks]
(c) A cast-iron surface 300 mm long and 180 mm wide is to be machined on a shaper with cutting-toreturn
ratio of 3 : 2. Cutting speed, feed and clearance are 24.6 m/min, 2 mm/double stroke and
30 mm respectively. The available ram strokes on the shaper are 28, 40, 60 and 90 strokes/min. If
the depth of cut is 3.5 mm, determine the time required to machine the surface.
[6 Marks]
(d) With the aid of a neatly labeled diagrams, illustrate any five tools used on a shaping machine
[5 Marks]
QUESTION FIVE [20 Marks]
a) Briefly explain the following parts of a drilling machine:
i. Pillar
ii. Quill
iii. Base
iv. Motor [4 Marks]
b) Explain briefly three main methods of creating small chips in drilling process. [3 Marks]
c) List five main features of properly ground drills. [5 Marks]
d) A hole of 30 mm diameter and 75 mm depth is to be drilled. The suggested feed is 1.3 mm per
rev. and the cutting speed is 62m/min. Assuming tool approach and tool overtravel as 6 mm,
calculate:
i) Spindle r.p.m.
ii) Feed speed
iii) Cutting time
iv) Material removal rate (MRR) [8 Marks]
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