Solved Anna University Question Papers (Reg 2017 / Dec 2018)

B.E./B.TECH. DEGREE EXAMINATION - NOVEMBER/DECEMBER 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 2017)

Answer ALL questions

Part A - (10 × 2 = 20 Marks)

1. What do you meant by core print?

A core print is the projection on a pattern. Core print forms a seat in the mould. The core is supported in the seat formed by the core print.

2. Make a note on loam mould.

For very large castings such as large cylinders, large bells, wheels, kettles, gear wheels, pans etc., moulding boxes and patterns cannot be used as it is more expensive. Such large castings are made by the use of loam moulding. Loam sand is a mixture of silica sand, water, graphite powder and more amount of clay. The mould made by using loam sand is called loam moulding. It is made by pit moulding method. Initially, the rough framework is made by bricks. The loam sand is applied over the brickwork. A sweep pattern is used to get the required shape of the mould. It is swept around the mould to remove excess sand. Plates and bars can be used to reinforce the brickwork. In this way, the mould cavity is made. Then it is dried. Now, the mould is ready for pouring.

3. What is the difference between brazing and braze welding?

Brazing:

In brazing, the base metal of the workpieces to be joined is not melted but filler makes the joint in metal. This filler metal in the form liquid is adhered to the base metal and the joint is made between two workpieces.

Braze welding:

Braze welding is the use of a bronze or brass filler rod coated with flux to join steel workpieces. Since braze welding usually requires more heat than brazing, acetylene or methylacetylene-propadiene (MAP) gas fuel is commonly used. It is used to produce joints of excellent strength in steel, in cast iron, and in copper and some copper alloys.

4. Why shielding of weld area during welding is required?

Shielding is used to prevent atmospheric reaction between molten metal and atmosphere (prevention of oxidation).

5. What do you meant by angle of bite?

The angle subtended by the centre of the roll with radial force in rolling operations is called angle of bite or angle of contact.

In other words, it can be defined as an angle between first contact of metal and radius of the roll. It joins the opposing rolls and the centres of them when metal is rolled. 

6. What do you meant by recrystallization temperature?

Recrystallization temperature is defined as the "minimum temperature at which the complete recrystallization of a metal takes place within a specified time".

7. Make a short note on hydro forming of sheet metal.

Hydroforming is a metal fabricating and forming process which allows the shaping of metals such as steel, stainless steel, copper, aluminum, and brass. It utilizes highly pressurized fluid to form metal. Hydroforming of sheet metal uses one die and a sheet of metal. The blank sheet is driven into the die by high pressure fluid on one side of the sheet forming the desired shape. It is an ideal process for producing complex geometries and is used by multiple industries such as automotive, aerospace, nuclear, and defense. 

8. What is meant by standoff distance in explosive forming process?

The distance at which the explosive charge is located at some distance away from the blank and its energy is transmitted through some fluid medium such as water is known as standoff distance.

9. Write short note on thermoset plastics.

The plastics which are hardened by heat effecting a non-reversible chemical change are called thermosetting plastics.

Thermosetting plastics do not soften on reheating and cannot be reworked. Thermosetting molecules are formed by condensation polymerization. The molecules of such type of plastics have three dimensional network and very strong binding force between molecules. The raw material for thermosetting plastics is in the form of liquid or solid. These types of plastics are polymerized when moulded or formed. It consumes. more time for formation.

10. Make a note on 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.

Crystalline sharp melting polymers such as nylon or polyethylene terephthalate PET are very much suited for film productions by melt casting techniques. Initially, the heated plastic powder is extruded by using extrude machines called extruder. In this extruding process, the thin film is produced.

After extruding the thin film, it is stretched by pulling rollers through the chilled drum in the reeling wheel. The thin film is cooled in the chilled drum and the rollers are used to pull the film from chilled drum. The reeling wheel is used to make the film roll.

Part B - (5 × 13 = 65 Marks)

11. (a) Enumerate about carbon-di-oxide (CO2) moulding.

Refer chapter 1.14.8 in Page 1.86.

Or

(b) Sketch a common hot chamber die casting machine, explain with its applications.

Refer Page 1.80.

12. (a) Explain the neat sketch the working principles of Gas Metal Arc welding. 

Refer chapter 2.7 in Page 2.24. 

Or

(b) Explain principle and two types of friction welding process. 

Refer chapter 2.15 in Page 2.60.

13. (a) Elucidate about the types of rolling stand arrangement.

Refer chapter 3.11 in Page 3.41.

Or

(b) (i) Explain about the preparation requirement before wire drawing process.

Refer chapter 3.16.1 in Page 3.64.

14. (a) Explain the principle of magnetic pulse forming with its advantages and limitations.

Refer chapter 4.14.6 in Page 4.52.

Or

(b) Explain with neat sketch hydro forming. Mention its advantages and limitations.

Refer chapter 4.14.1 in Page 4.42.

15. (a) How is a plastic component manufactured in compression moulding.

Refer chapter 5.4.1 in Page 5.30.

Or

(b) Explain procedure and guidelines for making a solvent bonding of plastics.

Refer chapter 5.7.1.1 in Page 5.37.

Part C - (1 × 15 = 15 Marks)

16. (a) Explain with necessary sketches applications of following sheet metal forming operations: Shaving, slitting, notching.

Refer Page 4.9 & 4.10.

Or

(b) Explain the requirements for the pattern material. Discuss the suitability of following materials: Wood, aluminium, rubber, bras and white metal.

Refer chapter 1.6 in Page 1.7.