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Emt 2103 Workshop Processes And Practice Ii Question Paper
Emt 2103 Workshop Processes And Practice Ii
Course:Bachelor Of Science In Mechatronics
Institution: Dedan Kimathi University Of Technology question papers
Exam Year:2010
EMT 2103 WORKSHOP PROCESSES & PRACTICE II 2ST SEMESTER 2010 Page 1 of 3
Page 1 of 3
KIMATHI UNIVERSITY COLLEGE OF TECHNOLOGY SECOND SEMESTER EXAMINATIONS 2010 FIRST YEAR EXAMINATIONS FOR THE DEGREE OF BACHELOR OF SCIENCE IN MECHATRONIC ENGINEERING
EMT 2103 WORKSHOP PROCESSES AND PRACTICE II
DATE: 9TH DECEMBER 2010 TIME. 200PM – 4.00PM INSTRUCTIONS
1. The paper has FIVE questions.
2. Question 1 carry 30 marks, and the rest 20 marks each.
3. Attempt QUESTION 1 and any OTHER TWO questions.
Question 1 (Compulsory)-30 Marks
(a) (i) State three factors you would consider when selecting a material for a twist drill (1.5 marks)
(ii) State any three criteria used in specifying a drilling machine (3 marks) (iii) How long will it take to drill a hole of 20mm diameter in a mild steel plate of 60mm thickness when the cutting speed is 25m/min and feed of 0.15 mm/rev? (4 marks)
(b) (i) Briefly describe how braze welding is performed (3 marks)
(ii) State two advantages of braze welding (2 marks) (iii) State three functions of flux in heat joining processes (1.5 marks)
(c) (i) With the help of neat sketches, describe how a shell mould is prepared (6 marks)
(ii) State two advantages of shell moulding over sand moulding (2 marks) (iii) State two circumstances under which casting processes are preferred over other manufacturing processes (1 mark)
(d) (i) State the three gas welding flames and one application of each (3 marks)
(ii) Under what form is acetylene gas stored in the gas cylinder and why? (2 marks) (iii) State the two functions of gas regulators in gas welding (1 mark)
EMT 2103 WORKSHOP PROCESSES & PRACTICE II 2ST SEMESTER 2010 Page 2 of 3
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Question 2 (20 marks)
(a) Specify the type of drilling machine suitable for the following operations and explain the design features which makes them suitable:
(i) Several holes to be drilled at different locations on a large workpiece (3 marks)
(ii) Holes to be drilled at an angle to the vertical axis (2 marks)
(iii) Mass production in related operations such as holes of different sizes, reaming or counter-boring on a single part (3 marks)
(b) (i) Explain what flutes are and their functions in twist drills. (2 marks)
(ii) Why do reamers have left hand spiral flutes as opposed to that of twist drills, which have right hand? (2 marks) (iii) Explain what would happen if drilling with an inaccurately ground twist drill such that;
1. The lips are of unequal length (1 mark)
2. The cutting edges are at different angles to the drill axis (1 mark)
(c) (i) Explain the difference between a jig and a fixture. (1 mark)
(ii) For what type of jobs are drilling jigs and fixtures suitable? (1 mark) (iii) Name two types of bushes used in drilling jig plates. For what type of application is each bush suitable? (2 marks)
(d) State four safety precautions observed when using the drilling machine (2 marks)
Question 3 (20 marks)
(a) What do you understand by the following terms; (1.5 marks)
(i) Autogenous welding
(ii) Homogenous welding
(iii) Heterogenous welding
(b) (i) What are the two main edge preparations performed in welding? Explain why they are performed. (2 marks)
(ii) With aid of neat diagrams, describe the three basic types of lap welded joints (3 marks) (iii) Distinguish between straight polarity and reversed polarity in arc welding. Under what circumstances is each preferred? (3 marks)
(c) (i) With the aid of a sketch, describe the basic electric arc welding circuit (3 marks)
(ii) State the functions of the following materials used in electrode coatings: (2.5 marks)
1. Carbonaceous matter
2. Silica, SiO2
3. Titanium oxide, TiO2
4. Calcium carbonate, CaCO3
5. Sodium silicate, Na2SiO3
(iii) State two conditions necessary in welding high carbon steels (2 marks)
EMT 2103 WORKSHOP PROCESSES & PRACTICE II 2ST SEMESTER 2010 Page 3 of 3
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(d) (i) What is the main disadvantage of using alternating current in arc welding? How can the disadvantage be overcome? (2 marks)
(ii) State two safety precautions that should be observed when performing arc welding (1 mark) Question 4 (20 marks)
(a) (i) What is recrystallation temperature? (1 mark)
(ii) State three advantages of cold working over hot working of metals (3 marks)
(b) (i) With the aid of sketch, describe the principle of indirect extrusion process (4 marks)
(ii) State the two main limitations of indirect extrusion (2 marks)
(c) (i) State and explain any four good properties of moulding sand (8 marks)
(ii) State any two types of sand binders giving an example of each (2 marks) Question 5 (20 marks)
(a) (i) State four factors that determine the quality of surface finish of a shaped surface (2 marks)
(ii) With the help of a neat sketch, describe the main parts of a shaping machine (8 marks)
(b) (i) State four factors considered in the choice between a shaper and a planner for a machining operations (2 marks)
(ii) With the help of neat diagrams, describe any three work holding devices used on the shaper machine (6 marks) (iii) State any four differences between a shaper and a planner (2 marks)
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