Production

Q.

Taylor's tool life equation is given by $V{T}^n=C$ where V is in m/min and T is in min. In a turning operation, two tools X and Y are used. For tool X, n = 03 and C = 60 and for tool Y, n = 0.6 and C = 90. Both the tools will have the same tool life for the cutting speed (in m/min, round off to one decimal place) of

1. 40

Q.

What is the perimeter of a cylinder?

Q. In an orthogonal cutting test on mild steel, the following data were obtained
Cutting speed : $40m/min$
Depth of cut : $0.3mm$
Total rake angle : $+5^o$
Chip thickness : $1.5mm$
Cutting force : $900N$
Thrust force : $450N$
Using Merchant's analysis, the friction angle during the machining will be

1. ${26.6}^o$
2. ${31.5}^o$
3. ${45}^o$
4. ${63.4}^o$

Q. $\text{The bending force required for a 1.5 mm thick steel (having ultimate tensile strength 800 MPa) sheet of 1 m length to be bent in a wiping die (K = 0.33) is kN. The die radius used is 3 mm. (By using the governing equation = bending force,}{F}_b=\frac{kL\sigma t^2}{W})\text{Every symbol has their using meaning.}$

1. 79.2

Q.

How do I find the value of $\tan \left(225°\right)$.

Q. Arrange the processes in the increasing order of their maximum material removal rate.
Electrochemical Machining (USM)
Electron Beam Machining (EBM)
Laser Beam Machining (LBM)
Electric Discharge MAchining (EDM)

1. USM, LBM, EBM, EDM, ECM
2. EBM, LBM, USM ECM, EDM
3. LBM, EBM, USM, ECM, EDM
4. LBM, EBM, USM, EDM, ECM

Q. In a shaper machine, the mechanism for tool feed is

1. Geneva mechanism
2. Whitworth mechanism
3. Ratchet and Pawl mechanism
4. Ward-Leonard system

Q. During the electrochemical machining (ECM) of iron (Atomic weight = 56, valency = 2) at current of 1000 A with 90% current efficiency the material removal rate was observed to be 0.26 cc/s. If Titanium (atomic weight = 48, valency = 3) is machined by the ECM process at the current of 2000 A with 90% current efficiency, the expected material removal rate in gm/s will be

1. 0.11
2. 0.23
3. 0.30
4. 0.52

Q. The true stress-true strain curve is given by $\sigma =1500{\epsilon }^{0.45},$ where the stress $\sigma$ is in MPa. The mean flow stress at the maximum load (in MPa) is

1. 1047
2. 427
3. 722
4. 397

Q. Assertion $\left(A\right)$: Grinding needs higher specific cutting energy than milling.
Reason $\left(R\right)$: Milling cutter material is harder than abrasive grains

1. Both $A$ and $R$ are true and $R$ is the correct explanation of $A$
2. Both $A$ and $R$ are true but $R$ is not a correct explanation of $A$
3. $A$ is true but $R$ is false
4. $A$ is flase but $R$ is true

Q.

What is the shearing angle?

Q. The time taken to drill a hole through a $25mm$ thick plate with the drill rotating at $300rpm$ and moving at a feed rate of $0.25mm/rev$ is

1. $10sec$
2. $20sec$
3. $60sec$
4. $100sec$

Q. The maximum reduction in cross-sectional area per pass (R) of a cold wire drawing process is

R = $1-e^{-(n+1)}$

where n represents the strain hardening coefficient. For the case of a perfectly plastic material, R is

1. 0.865
2. 0.826
3. 0.777
4. 0.632

Q. In an orthogonal cutting test with a tool of rake angle 15 deg, the following observations were made: chip thickness ratio = 0.37, horizontal cutting force = 1000 N, vertical cutting force = 1500 N.

The machining constant for the given machining operation is

1. ${76.82}^{\circ }$
2. ${65}^{\circ }$
3. ${55.8}^{\circ }$
4. ${49}^{\circ }$

Q. In a single pass rolling operation, a 20 mm thick plate with plate width of 100 mm, is reduced to 18 mm. The roller radius is 250 mm and rotational speed is 10 rpm. The average flow stress for the plate material is 300 MPa. The power required for the rolling operation in kW is closest to

1. 15.2
2. 18.2
3. 30.4
4. 45.6

Q. It is required to punch a hole of diameter $10mm$ on a sheet of thickness $3mm$. The shear strength of the work material is $420MPa$. The required punch force is

1. $19.78kN$
2. $39.56kN$
3. $98.9kN$
4. $359.6kN$

Q. In a rolling process, a sheet of 25 mm thickness is rolled to 20mm thickness. Roll is of 600 mmdiameter and it rotates at 100 rpm. The roll strip contact length will be

1. 5 mm
2. 39 mm
3. 78 mm
4. 120 mm

Q. In an orthogonal cutting test, the cutting force and thrust force were observed to be 1000 N and 500 N, respectively. If the rake angle of tool is ${11.31}^{\circ }$, the coefficient of friction in chip-tool interface will be [given sin 11.31 = 0.2]

1. 1.27
2. 0.63
3. 0.32
4. 0.78

Q. A solid cylindrical stainless steel work piece of 200 mm diameter and 150 mm height. This component is reduced by 50% in height with flat die in open die forging. Assuming the flow stress of the material as 1000 MPa and the coefficient of friction to be 0.2, the estimated forging force at the end of the stroke is

1. 20.8 kN
2. 31 kN
3. 78.6 kN
4. 82.11 MN

Q. The primary mechanism of material removal in electrochemical machining (ECM) is

1. chemical corrosion
2. etching
3. ionic dissolution
4. spark erosion

Q. Using the Taylor's tool life equation with exponent n = 0.5. If the cutting speed is reduced by 50%, the ratio of new tool life to original tool life is

1. 4
2. 2
3. 1
4. 0.5

Q. In blanking operation the clearance is provided on

1. The die
2. The punch
3. Both die and punch equally
4. Neither and punch nor the die

Q. Calculate the bite angle when rolling plates 12 mm thick using work rolls 600 mm diameter and reducing the thickness by 3mm

1. 5.73

Q. The standard specification of a grinding wheel is
$A-46-M-6-V-21$. It means a wheel of

1. Aluminum oxide of mesh size $6$
2. Boron carbide of mesh size $46$
3. Aluminum oxide of mesh size $46$
4. Silicon carbide of mesh size $6$

Q. The relationship between true strain $\left({ϵ}_T\right)$ and engineering strain $\left({ϵ}_E\right)$ in a uniaxial tension test is given as

1. ${ϵ}_E=ln(1+{ϵ}_T)$
2. ${ϵ}_E=ln(1-{ϵ}_T)$
3. ${ϵ}_T=ln(1+{ϵ}_E)$
4. ${ϵ}_T=ln(1-{ϵ}_E)$

Q. The blank diameter used in thread rolling will be

1. Equal to the major diameter of the thread
2. Equal to the pitch diameter of the thread
3. Little higher than the minor diameter of the thread
4. Little higher than the pitch diameter of the thread

Q. A cylinder of 25 mm diameter and 100 mm length is turned with a tool, for which the relation $V{T}^{0.25}$ = 55 is applicable. The cutting velocity is 22 m/min. For a tool feed of 0.046 mm/rev, the number of tool regrinds required to produce 425 cylinders is

1. 12
2. 22
3. 43
4. 85

Q. Machinability of steels is improved by the addition of

1. Sulphur
2. Silicon
3. Phosphorous
4. All of the above

Q. A three-start external square thread of 12 mm pitch and outside diameter of 65 mm is to be cut on a centre lathe which has a 7 mm pitch lead screw. Depth of thread to give 0.14 clearance is _______ mm.

1. 6.14

Q. The rake angle in drill

1. Increase from centre to periphery
2. Decreases from centre to periphery
3. Remains constant
4. Is irrelevant to the drilling operation