THEORY EXAMINATION (SEM–IV) 2016-17 MANUFACURING TECHNOLOGY

B.Tech Engineering 0 downloads

₹29.00

Course: B.Tech (Mechanical Engineering)
Subject Code: EME405
Subject Title: Manufacturing Technology
Exam Type: Theory (Semester IV, 2016–17)
Duration: 3 Hours
Maximum Marks: 100

SECTION – A (10 × 2 = 20 Marks)

Short, conceptual questions testing fundamental manufacturing knowledge

No.	Question	Concept Summary
(a)	What is manufacturing? How is it classified?	Conversion of raw materials into finished goods; classified as primary (casting, forming), secondary (machining, joining), tertiary (finishing, inspection).
(b)	Elastic vs Plastic Deformation	Elastic: temporary deformation; Plastic: permanent deformation beyond yield point. Affected by temperature, strain rate, grain size, and impurities.
(c)	Open Die vs Closed Die Forging / Hot vs Cold Working	Open-die: free deformation; Closed-die: confined shape; Hot-working improves ductility; Cold-working increases strength and surface finish.
(d)	Wire Drawing and Deep Drawing	Wire drawing: reduces diameter by pulling wire through die; Deep drawing: converts sheet into cup-like shapes.
(e)	What is Extrusion?	Process of forcing metal through a die to form long rods or tubes of uniform cross-section.
(f)	Rolling Process & Its Types	Reduction of metal thickness by compressive forces between rotating rolls. Types: hot, cold, and ring rolling.
(g)	Die and Punch Assembly & Stripper Plate Function	Stripper plate removes blank/punched part from punch; prevents sticking and ensures clean shearing.
(h)	Role of Lubricant in Metal Forming	Reduces friction, tool wear, temperature, and improves surface finish.
(i)	Jigs vs Fixtures	Jigs guide cutting tools; Fixtures hold workpieces securely.
(j)	Thermoplastics vs Thermosetting Plastics	Thermoplastics soften on heating; thermosets harden permanently through curing.

SECTION – B (5 × 10 = 50 Marks)

Descriptive and derivation-based questions combining mechanics and process knowledge

Q. No	Topic	Core Explanation
(a)	Pressure Distribution in Forging (Sliding Friction)	Derive pressure as a function of friction factor, geometry, and deformation under sliding contact.
(b)	Pressure Distribution in Forging (Sticking Friction)	Full sticking assumption → higher pressure gradient; used for low-lubricated forging.
(c)	Yield Criteria	Tresca (maximum shear stress) and Von Mises (distortion energy) theories. Relation: k=σy3k = \frac{\sigma_y}{\sqrt{3}}k=3σy.
(d)	Drawing Stress in Wire Drawing or Extrusion	[
\sigma_d = \sigma_y \ln \frac{A_0}{A_f} (1 + \mu \cot \alpha)
] where μ\muμ = friction coefficient, α\alphaα = die half-angle.
(e)	Radial Stress in Deep Drawing	Derive expression for σr=Krln⁡rmr\sigma_r = \frac{K}{r} \ln \frac{r_m}{r}σr=rKlnrrm; also discuss prevention of bottom fracture.
(f)	Centrifugal Casting & Defects	Molten metal poured into rotating mould; common defects: blowholes, inclusions, shrinkage cavity, and hot tears.
(g)	Advantages & Limitations of Die Casting and Investment Casting	Die casting → high accuracy, mass production; Investment → fine surface finish, intricate shapes but costly.
(h)	Pattern & Allowances	Pattern → replica of casting. Allowances: shrinkage, machining, draft, rapping, distortion — to ensure dimensional accuracy.

SECTION – C (2 × 15 = 30 Marks)

Numerical derivations, design, and advanced process analysis

Q3. (a) Properties of Moulding Sand

Refractoriness (resistance to high temperature)

Permeability (gas escape)

Cohesiveness (strength of mould)

Flowability (ability to compact and reproduce details)

Adhesiveness (to pattern and flask)

Elements of Gating System: Pouring basin, sprue, runner, ingate, and riser.

(b) Powder Metallurgy Steps:

Powder Production (atomization, reduction)

Blending & Mixing

Compaction

Sintering (heat treatment below melting point)

Finishing (secondary operations)

Q4. (a) Sprue Design for Aspiration-Free Flow

To avoid air aspiration:

A3A2=h2h3\frac{A_3}{A_2} = \sqrt{\frac{h_2}{h_3}}A2A3=h3h2

where A2,A3A_2, A_3A2,A3 are cross-sectional areas at top and bottom, and h2,h3h_2, h_3h2,h3 are respective heights.

(b) Riser Design Ratio
For economical risers:

Side riser → hd=1\frac{h}{d} = 1dh=1

Top riser → hd=12\frac{h}{d} = \frac{1}{2}dh=21
In both cases:

VA=d6\frac{V}{A} = \frac{d}{6}AV=6d

which ensures optimal solidification and feeding efficiency.

Q5. (a) Cupola Furnace

Charging Cupola: Cylindrical furnace for cast iron melting.
Zones: Crucible zone → Melting → Combustion → Preheating.
Sketch: Includes tuyeres, wind belt, slag hole, charging door.

(b) CAINE’s Method for Riser Design

Vr=Vc((Ts)r(Ts)c)nV_r = V_c \left( \frac{(T_s)_r}{(T_s)_c} \right)^nVr=Vc((Ts)c(Ts)r)n

where TsT_sTs = solidification time, VVV = volume.
Used to size riser ensuring directional solidification.
NDT Methods: Radiography, Ultrasonic, Magnetic particle, Dye penetrant tests.