PRIMARY MANUFACTURING PROCESS
PRIMARY MANUFACTURING PROCESS
PRIMARY MANUFACTURING PROCESS
PRIMARY MANUFACTURING PROCESS [ME 403]
[ME 403]
[ME 403]
[ME 403]
QUESTION BANK
1. What is meant by manufacturing? Give a classification of manufacturing processes. 2. State about the steps involved in casting process/foundry practice, in sequence.
3. What is a pattern? Why and how a pattern may differ in shape and size, to some extent, in many cases, from the casting/cast product?
4. Why is wood widely used as pattern material? (What are the advantages of use of wood as pattern material?). Also mention about the disadvantages.
5. Name and discuss about pattern allowances (shrinkage allowance, draft allowance, shake allowance, distortion allowance – camber, machining allowance). Show relevant sketches where applicable {especially for distortion allowance, draft allowance -both for external and internal surfaces}. Also state about the different stages of shrinkage with graphical presentation and mention which stage of shrinkage is taken care of by shrinkage allowance on pattern.
6. Discuss about different types of pattern with illustrative sketches (solid/single piece pattern, split pattern, loose piece pattern, gated pattern, match plate pattern, cope and drag pattern, sweep pattern, skeleton pattern).
7. Name and state about various types of pattern materials that are used in foundry practice. 8. State about the factors/consideration on which selection of pattern material will depend. 9. What are the advantages of metal as pattern material? What are the different types of metals
that are used for pattern? Discuss about wax, plaster of paris and old casting as pattern materials.
10. What is meant by green sand? Write its constituents.
11. Name different types of clay/binder used in moulding sand. What are meant by additives? Name some additives used in moulding sand and their usefulness.
12. Classify moulding processes based on the type of moulding sand used in the process. (Discuss about green sand moulding, dry sand moulding, skin dried moulding, loam sand moulding, CO2 moulding etc.)
13. What are the drawbacks of green sand moulding?
14. State about facing sand, parting sand and backing sand. What is known as natural moulding sand and synthetic sand?
15. What is pit moulding? Describe with a neat sketch. State about its applications as well.
16. Name and discuss about the desirable characteristics/properties of moulding sand (Discuss about green strength, dry strength, hot strength, adhesiveness, cohesiveness, flow ability/plasticity, permeability, collapsibility, refractoriness and grain size)
17. Describe the following sand testing methods (with necessary sketches where applicable): clay content test, AFS grain fineness test, mould hardness test, moisture content test, permeability test and green strength test.
18. State about the considerations for good design of a gating system. What is the main purpose of the gating system? Show a sketch for a typical gating system, indicating its components (pouring
cup/basin, down sprue, runner, gates etc. Also show in sketches various types of pouring cups/basins in the gating system, with strainer, skim bob etc.)
19. Define permeability number. Calculate the permeability number of a sand specimen if it takes 1min 15 s to pass 2000 cm3 of air at a pressure of 10 g/cm2. The diameter of the standard sand specimen = 50.8 mm and height of the specimen 50.8 mm.
20. Determine the dimensions of the wooden pattern to be used for a finished casting of length 200 mm, width 150 mm and height /depth 100 mm. Assume shrinkage allowance on pattern as 10.5mm/m. Neglect other types of pattern allowance.
21. What is a master pattern? Explain the double shrinkage and machining allowances in this context.
22. Deduce the expressions for filling times of the mould for i) a simple top gating system ii) a simple bottom gating system.
23. With illustrative sketches, describe different types of gates: simple top gate, simple bottom gate, parting line gate, step gate, whirl gate, horn type gate etc. State about the advantages and disadvantages of both top gating and bottom gating systems.
24. What is meant by gating ratio? State about its significance. Mention about pressurised and non-pressurised gating systems and their relative advantages and disadvantages.
25. What is meant by aspiration effect? Explain it clearly. Why is generally down sprue made taper? Show, with necessary deduction, that a straight down sprue with no taper will cause aspiration, which can be avoided by making the sprue taper.
26. Calculate the filling times for both top and bottom gating systems to fill up a cylindrical casting of 40 cm diameter and 20 cm height. Static head available for both the cases is 25 cm. The gate diameter is 2 cm.
27. A mould 60 cm x 40 cm x 15 cm is to be filled by liquid metal in sand casting. Determine the time taken to fill up the mould by i) top gating system ii) bottom gating system. Cross sectional area of the gate in each case is 6 cm2.
28. A solid carbon steel block of final dimension of 100mm x 75 mm x 60 mm is to be made by green sand casting. Find the dimensions of the wooden pattern taking into account of shrinkage allowance as 3 % and machining allowance as 4 %.
29. A sample of 50 g sand was taken and placed on the top sieve of standard stack of sieves in a sieve shaker device. After shaking for 15 minutes, the amount retained in each sieve and pan is given in the following table. Determine the grain fineness number and specify the application for which this sand is suitable.
AFS mesh/sieve no. 6 12 20 30 40 50 70 100 140 200 270 Pan Multiplier 3 5 10 20 30 40 50 70 100 140 200 300 Retained sand weight, g 0 0 2 3 2.5 5 6 5 14 4 3 5
30. Write about the functions of a riser. What is meant by directional solidification? Discuss how does riser design take care of directional solidification? What is a blind riser? Describe with a sketch. State about the size and location of risers.
31. What are chills? Why are they used in certain cases? State about external and internal chills. Show them in sketches as well.
32. Write and explain Chvorinov’s rule in the context of solidification of a casting. What is Caine’s rule? Write Caine’s equation. Define freezing ratio. Show the graphical plot (risering curve) representing Caine’s equation. Explain how Caine’s equitation/graphical plot/Caine’s rule is used to determine riser size.
33. Determine the dimensions of a cylindrical riser to be used for casting an Aluminium cube, each side = 15 cm. The volume shrinkage of Aluminium is 6.5%.
34. Calculate the size of a cylindrical riser (diameter = height) necessary to feed a steel slab casting 25 cm x 25 cm x 5 cm with a side riser.
35. Prove that the volume/area ratio for most compact economical cylindrical top riser of height h and diameter d is d/6 and d/h = 1.
36. What will be the solidification time for a 1000mm diameter and 30 mm thickness casting of aluminium if the mould constant is 2.2s/mm2?
37. Compare the solidification time for casting of three different shapes of same volume: cube, cylinder ( height = diameter; h = d ) and sphere.
38. With illustrative sketches describe core, core print and chaplet. Explain functions of each. 39. What is meant by green sand core and what by dry sand core? Show them in sketches.
40. With sketches describe different types of cores: horizontal core, vertical core, balanced core, drop core, cover core, hanging core, and kiss core.
41. Describe the procedure of core making. What is a core box? What is the composition of dry sand core?
PART B
42. What is meant by recrystallization? State about its significance in respect of metal forming. 43. What are meant by hot working and cold working? State about the advantages and
disadvantages of both. What is meant by strain hardening/ work hardening? What are the effects of the same on the mechanical properties of the material?
44. Describe the basic idea of forging process. What are meant by drawing out, upsetting and necking /fullering, edging and cogging operations in forging. What is meant by forge ability? 45. State about the importance of heating and finishing temperatures in forging.
46. With simple sketches describe open die /die-less forging, closed die forging. Also discuss about drop forging and press forgings. Distinguish between drop and press forging and mention about their applications. What is flash? Show it in a sketch and mention how it can be removed. 47. Show a typical die in closed die ( impression die ) forging indicating the important features on it (
upper die, lower die, draft, gutter, parting line, flash region, fillet, rib, web and land)
48. Name some widely used equipment/tools used in forging/smith forging (anvil, fullers, swage etc.)
49. With an illustrative sketch explain the basic principle of rolling operation. What is hot rolling and what is cold rolling? Discuss about typical uses of rolling process; mention names of typical products generally obtained by rolling process, show various sections of rolled products.
50. Explain the followings: angle of bite, forward slip, backward slip, neutral plane and draft in reference to rolling process. What is the significance of the value of the angle of bite?
51. Name different types of rolling mills and describe each of them with illustrative sketch (two high mill, three high mill, four high mill and cluster mill.). What are back up rolls and why are they used? Show a sketch.
52. Why are rolls often provided with convex camber?
53. Discuss about roll forging and rotary swaging with illustrative sketches.
54. With neat sketches describe forward (direct) extrusion and backward (indirect) extrusion processes. Write about the advantages and disadvantages of each of these processes (/ Compare these two processes.) What are meant by hot extrusion and cold extrusion?
55. Mention about some applications of extrusion process/typical products produced by extrusion process.
56. With a neat sketch describe wire drawing process.
57. Show a typical die used for wire drawing and label and state about its different parts/zones. 58. Discuss about the materials used for die in wire drawing operation.
59. In a flat rolling operation a 400 mm wide steel strip having thickness of 10 mm is reduced to 8 mm by using rolls of diameter 600 mm. Find the contact length of the roll strip with work piece. 60. A strip with a cross section of 150 mmx6mm is being rolled with 20% reduction in area, using
400 mm diameter steel rolls. Before and after rolling, the shear yield stresses of the material are 0.35 kN/mm2 and 0.40 kN/mm2 respectively. Calculate i) the final strip thickness ii) average shear yield stress iii) the angle subtended by the deformation zone at the role centre.
61. Using an open die forging operation, solid cylindrical piece of stainless steel, having 100 mm diameter, 72 mm height is reduced to 60 mm at room temperature. Assuming coefficient of friction as 0.22 and flow stress at required true strain as 1000 MPa, calculate the forging force at the end of the (hammer) stroke.
62. A 300 mm wide strip 25 mm thick is fed through a rolling mill with two powered rolls of radius = 250 mm. The thickness is to be reduced to 22 mm in one pass with a roll speed of 50 rev/min. The work material has a flow curve defined by K = 275 MPa and n = 0.15. The coefficient of friction between the rolls and the work is assumed to be 0.12. Determine if the friction is sufficient to permit the rolling operation to be accomplished. If so, calculate the roll force, torque and horsepower.
63. State about extrusion defects.
64. Distinguish between cold working and hot working process. 5 65. What is the significance of Recrystalization Temperature in Metal working Process. 66. Write down the principles of wire drawing with a neat sketch. 6 67. Distinguish between cold working and hot working process. 5 68. Explain the process of Hydrostatic Extrusion with a sketch. 5
69. Distinguish between Forward Extrusion and Backward (Reverse) Extrusion.
71. Why close tolerances can not be maintained in hot working of metals? 2
72. Distinguish between Extrusion and Drawing with a sketch. 3
73. Explain with neat sketches the step by step operation of upsetting a bar. 5
74. Differentiate between Press Forging and Drop Forging. 5
75. What are the different types of Forging processes practiced. 6
76. What are the common Forging defects and what are the remedial measures to be taken?5 77. Explain the influences of lubrication of dies during forging operations 5
78. Explain with neat sketches the step by step operation of upsetting a bar. 5
79. What are the common Forging defects and what are the remedial measures to be taken?5 80. Explain the influences of lubrication of dies during forging operations 5
81. What do you understand by Flash in Forging. Explain with the help of a sketch. 3 82. How do you compare forged components with a cast component? 3
83. Explain how material properties are improved by Forging? 3
84. Distinguish between cold rolling and hot rolling with respect to blank temperatures, relative advantages and applications. 4
85. What should be the direction of rotation of the two rollers during cold rolling of mild steel sheets. 1
86. Write down the principle of rolling. 2
87. Give sketches of different sections generally being manufactured in rolling. 1
88. Sketches different roll arrangements in Rolling stand. 4
89. What is camber? 1
90. Write down the principle of Rolling. Give sketches of different section generally being manufactured in Rolling. 6
91. In a single flat rolling operation a 400 mm wide steel strip having thickness of 10 mm is reduced to 8 mm by using rolls of diameter 600 mm. Find the contact length of the roll strip with the work piece. 5
92. Explain Plasma arc welding and ultrasonic welding in brief. 7
93. In Rolling process, sheet of 25 mm thick is rolled to 20 mm thickness. Roll is of diameter 600 mm and it rotates at 1000 rpm. What will be the Roll Strip contact length? 4
94. Distinguish between cold rolling and hot rolling with respect to blank temperatures, relative advantages and applications. 4
95. What should be the direction of rotation of the two rollers during cold rolling of mild steel sheets. 1
96. Write down the principle of rolling. 2
97. Give sketches of different sections generally being manufactured in rolling.1 98. Sketches different roll arrangements in Rolling stand. 4
99. What is camber? 1
100. Write down the principle of Rolling. Give sketches of different section generally being manufactured in Rolling. 6
101. Explain the terms: Ingot, Slab, Bloom, Billet,
102. Enumerate the difference between Coining and Embossing.
104. Why are clearance and shear angles provided in Press tool Punch? 4
105. What is Flash? Explain with a neat sketch. 3
106. Why are clearances and shear angles provided in press tool punch? 4
107. Differentiate Punching and Blanking with neat sketch. 4
108. Write down short notes: Blanking, Piercing, Ironing, 109. Differentiate between TIG welding and MIG welding processes. 5
110. List out the factors on which the selection of welding process depends. 5
111. Explain Electron beam welding with a neat sketch. 10
112. List out any five welding defects with their reasons and remedies. 5
113. What is Braze welding? Give five application of Braze Welding. 5
114. Difference between Electro slag welding and Electro gas welding 5
115. Distinguish between Welding, Brazing and soldering. 5
116. Effect of DCSP (DCEN) and DCRP (DCEP) and AC power source on the Arc welding components. (SP = Straight Polarity; RP = Reverse Polarity) 5 117. Explain Sub-merge arc Welding process and its advantages over other arc welding processes? 5
118. Describe with the help of sketches the three types of oxy-acetylene flames. 5
119. With the aid of sketch explain the process of TIG. 5
120. Explain with neat sketches the process of Sub-merged arc Welding process and its applications. 6
