Solved Anna University Question Papers (Reg 2013 / Dec 2018)

B.E./B.TECH. DEGREE EXAMINATION - April/May 2018

Third Semester/Fifth semester

Mechanical Engineering

ME 6302-MANUFACTURING TECHNOLOGY-I

(Common to Industrial Engineering and Industrial Engineering and Management) and Mechanical and Automation Engineering)

Time: Three hours      Maximum: 100 Marks

(Regulation 2013)

Answer ALL questions

Part A - (10 × 2 = 20 Marks)

1. List out the various materials used for pattern making.

The commonly used pattern making materials are given below:

1. Wood-Teak wood, mahogany, white pine, etc.

2. Metals - Cast iron, brass, aluminium, white metal etc.

3. Plaster

4. Plastics

5. Wax.

2. State the advantages of investment casting.

1. Complex shapes can be cast accurately.

2. Surface finish is very good.

3. High accuracy can be maintained.

4. Number of casting can be made at a time.

5. Undercut and other intricate shapes which would not allow the withdrawal of a normal pattern are easily obtained.

6. Unmachinable alloys can be cast.

3. What is the principle of thermit welding?

Thermit welding is a fusion welding process. In this process, neither arc is produced to heat parts nor flames are used. For getting high temperature, the exothermic reaction between components of the Thermit is used. Thermit or alumino-thermic is the name given to a mixture of finely divided metal oxide and aluminum powder. To obtain exothermic reaction, the commonly utilizing composition is iron oxide red powder (Fe3O4) with aluminium powder (Al). The molten metal produced by the reaction acts as a filler material and joins the workpieces after solidification.

4. How do you specify an electrode?

An electrode is specified by an alphabet prefix followed by a 4-digit or 5-digit number. For example, in an electrode E6010, the prefix "E" designates an arc welding electrode. The first two digits of a 4-digit number and the first three digits of 5-digit number indicate minimum tensile strength. For example, E6010 is a 60,000 psi tensile strength electrode while E10018 designates a 100,000 psi tensile strength electrode.

The next to last digit indicates position. The "1" designates an all position electrode, "2" is for flat and horizontal positions only; while "4" indicates an electrode that can be used for flat, horizontal, vertical down and overhead. The last 2 digits taken together indicate the type of coating and the correct polarity or current to use shown below:

5. Name the defects in rolled parts.

1. Surface defects

2. Internal structural defects.

3. Porosity, cavity and blow hole

4. Longitudinal stringers

5. Lamination

6. Alligatoring

7. Laps

8. Flakes or cooling cracks

9. Scratches.

6. What is piercing operation?

Making a blind or through holes with the help of a punch in the metal is known as piercing. Piercing may be followed by punching to produce a hole in the part. Piercing is also performed to produce hollow regions in forgings using a single acting auxiliary equipment. Piercing force depends on the punches cross sectional area, tip geometry, strength and friction of the material.

7. What is shear angle in sheet forming?

The angle about which the vertical lines tilt is called shear angle. Shear angle initiates the shearing to complete piercing or blanking on the workpiece. So, it is provided on punches and dies.

8. What are the applications of superplastic forming process?

The process is increasingly being applied in the aerospace industry as a way of manufacturing very complex geometries. It is also used in

1. forming of automotive body panels.

2. forming of aircraft frames and skins.

3. diaphragm forming of plastics.

4. complex shaped parts such as window frames, seat structures etc.

9. Write any four thermosetting plastics used in industries.

1. Phenol formaldehyde

2. Polyester resin

3. Melamines

4. Phenol furfural

5. Epoxy resins

6. Silicones

7. Urea formaldehyde (Amino resin)

8. Alkyds

9. Polyurethanes

10. What is film blowing?

The process in which a continuous tubular film is fabricated of which diameter varies from few centimetres to many metres is called film blowing.

Part B (5 × 13 = 65 Marks)

11. (a) (i) Explain the different types of moulding sand and its properties.

Refer chapter 1.8.2 in Page 1.18 for types of moulding sand and chapter 1.8.3 in Page 1.19 for properties of moulding sand.

(ii) Write a note on defects in sand casting.

Refer chapter 1.18 in Page 1.93.

Or

(b) Explain the principle of shell moulding process with a neat sketch. Also, write its merits and demerits.

Refer chapter 1.14.1 in Page 1.73.

12. (a) Describe the Gas Tungsten Arc welding process with a neat sketch. Write its applications.

Refer chapter 2.6 in Page 2.21 for gas Tungsten arc welding process and chapter 2.6.1 in Page 2.23 for applications.

Or

(b) Explain the principle of Electron beam welding with a sketch. What are the characteristics and advantages of electron beam welding?

Refer chapter 2.13 in Page 2.54.

13. (a) What are the types of power hammers available? Explain the pneumatic hammer with a neat sketch.

Refer chapter 3.4.2 in Page 3.23.

Or

(b) Explain the principle of extrusion process. Compare the hot and cold extrusion process.

Refer chapter 3.18 in Page 3.74 for principle of extrusion process and chapters 3.19.1 & 3.19.2 in Page 3.75-3.78 for comparison.

14. (a) How curvatures are made on thin sheet metals, explain the suitable process with a neat sketch?

Refer chapter 4.11 in Page 4.33.

Or

(b) With a neat sketch, explain the rubber pad forming process. How does it differ from rubber hydro forming process?

Refer chapter 4.14.2 in Page 4.44.

15. (a) With a suitable sketch, describe the injection moulding process.

Refer chapter 5.3.1 in Page 5.10.

(b) Explain the following:

Or

(i) Film blowing

Refer chapter 5.3.7 in Page 5.24.

(ii) Bonding of thermoplastics.

Refer chapter 5.7 in Page 5.36.

Part C = (1 × 15 = 15 Marks)

16. (a) Suggest a suitable process for making of a bolt and elaborate the procedure.

Refer chapter 3.3.11 in Page 3.14.

Or

(b) Why the solid state welding processes are preferred over fusion welding process during the joining of dissimilar metals? Explain any one of the solid state welding process and highlight their specific advantages.

Refer chapter 2.15 in Page 2.60 for solid state welding process and chapter 2.15.2 in Page 2.63 for types of solid state welding process.