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Total No. of Page: 02 Roll No.:_____________

BE (EC/CO/IC/MPAE/IT/BT)

B.E. MID SEMESTER EXAMINATION September. 2015

MPAE – MA-301 Machine Tools, CNC and Automation Time: 1.30 Hours Max. Marks: 20

Note: 1. Attempt ALL Questions compulsory and in sequence order, All Questions Carry equal marks.

2. Give suitable sketches, where needed.

3. Assume suitable data, where necessary & Use appropriate units

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Section-A

1. ( 1+1+1+2 = 5)

a. State the purpose of having large number of spindle speeds and feeds in machine tools.

b. Explain different types of motions of the machine tools with neat sketches.

c. How do you classify different types of machine tool drives?

d. Schematically draw and explain a mechanism suitable for transmitting rotation from a shaft to another

non-parallel, non-intersecting, parallel and intersecting shaft with symbolic representation.

2. (1+2+2=5) a. Find 6 speeds for a lathe, to be used for rough turning and finishing mild steel work pieces ranging from 22 to

65 mm in diameter. Use standard speeds and standard step ratios. Roughening speed = 25 m/min; finishing

speed = 30 m/min.

b. A turning lathe is required to machine C.I. workpiece of 100 mm diameter with 6 mm roughing cut, at 25 m/min

speed, at 0.4 mm/rev feeds. Belt is used for drive, form motor to the gearbox input shaft at overall efficiency of

90%. The gearbox reduces the spindle speed, further to required value. Calculate the required power rating of

the motor. Take specific power for C.I is 3.5 kw/cc.

c. What is ray diagram? A machine tool spindle has six speeds: 355, 500, 710, 1000, 1400 and 2000. Select suitable

speed for a 7.5 kW motor. Draw the ray diagram for the arrangement, assuming belt drives. Take actual

minimum speed of the motor as 950 rpm.

Section-B

3. (5)

a. What is discrete feeding in manufacturing?

b. Automation enables high production rate at lowest cost. State five other major aspects.

c. What is AC? Its types? When it should be used?

d. Why angle of rise should be optimum for center board reciprocating feeder?

e. Write the equilibrium equation when the part fails to slide up in vibratory feeder.

f. How did first industrial revolution influence civilization?

g. Sketch a set up for feeding cylindrical components in only on orientation in vibratory feeder.

h. If the setting time is 80 minutes, machining time = 20 min., determine the no. of machines required.

If 25 components are to machine in a shift of 7 hours.

i. Explain customization & versatility with reference to feeders in manufacturing.

j. Name five variables which can be measured to control speed/feed in machining.

4. (5)

a. Explain product life, obsolescence & amortization in manufacturing automation.

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b. A company has invested Rs. X in infrastructure & it produces at a cost Rs. Y/component. If selling

price per component is Rs. Z, how many it should make to earn a profit of amount Rs. A. if the

investment is increase by amount Rs. B. How many should be made to earn additional profit of Rs. Z?

OR

What is GT, its advantages & various methods of its implementation?

c. Write equations for average time per components in mass, batch & job production.

d. State data required for determining optimum speed for maximum production rate. What is the major

assumption in this model?

e. Draw self-explanatory sketch of a copying lathe.

OR

Explain flexible automation in manufacturing, its advantages and limitations.

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