JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III MACHINE TOOLS Previous Question Paper (July/August - 2023 - R13)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What is the importance of nose radius?
Answer
The nose radius improves the surface finish of the machined part by reducing the height of feed marks left by the tool. It also increases the strength of the tool tip by dissipating heat more effectively and reducing stress concentration, thereby extending tool life.
Briefly discuss about chip breakers.
Answer
Chip breakers are devices or features on a cutting tool designed to break long, continuous chips into smaller, manageable pieces. They prevent the formation of dangerous, tangled bird-nest chips, improve operator safety, and protect the workpiece surface from scratches caused by chip rubbing.
Explain about types of mandrels used in lathe machine.
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Discuss about tool holders of lathe machine?
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Give the specifications of drilling machine.
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Differentiate between shaping, planning and slotting machines.
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Calculate the differential indexing for 241 and 89 divisions.
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Explain the tool life aspects of broaching, honing and lapping.
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What are the various factors to be considered in selection of grinding wheel?
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What is ‘grain size’ related to grinding? How it effects the performance of grinding process.
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Part B
Explain about Discontinuous chip and Continuous chip with built up edge.
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Explain the relations of orthogonal cutting forces.
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During an orthogonal machining operation on mild steel, the results obtained are: uncut chip thickness=0.25mm, chip thickness=0.75mm, width of the cut=2.5mm, rake angle=0, horizontal cutting force=900N, thrust force=400N. Compute the coefficient of friction between the tool and chip interface. Determine also the ultimate shear stress of the work material.
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Explain the relationship amongst the cutting velocity, chip flow velocity and shear velocity as applied to orthogonal cutting.
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Explain about chuck, lathe centers, collets, carriers and catch plates, and faceplate of lathe machine.
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Draw neatly the tool layout for turret automatic lathe machine.
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Draw the tool lay out for the component shown in the figure. Also, mention the sequence of operations performed on it.
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Explain principle parts of turret lathe with neat sketches.
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What is a shaper? Explain ram and table feed mechanism in a shaper.
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Write about work holding devices of drilling machine with suitable sketches.
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What is a slotter? Classify it, and explain the slotted disc mechanism with a neat sketch.
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What is a fine boring machine? Describe its construction and working in detail with a neat sketch.
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Make a neat sketch of universal milling machine indicating the various controls and constructional features. Give brief description.
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What type of imperfections left in machining operation can be corrected by honing and what conditions cannot be corrected by honing? How is it honing can correct irregularities but grinding cannot?
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Explain the general considerations in selection of milling cutters.
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Define Broaching and explain the principle of operation with neat sketches.
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List out factors which influence the performance of grinding wheel. Explain them in detail.
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Explain in detail any five types of bonds of abrasive grains.
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Describe about wheel wear and grinding ratio.
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Explain in detail some of the special grinding machines.
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