Solutions Of Fundamentals of Modern Manufacturing pptx

1 SOLUTIONS MANUAL FUNDAMENTALS OF MODERN MANUFACTURING: MATERIALS, PROCESSES, AND SYSTEMS Second Edition MIKELL P. GROOVER Professor of Industrial and Manufacturing Systems Engineering Lehigh University John Wiley & Sons, Inc., New York 2 PREFACE This is the Solutions Manual for the textbook Fundamentals of Modern Manufacturing: Materials, Processes, and Systems (Second Edition). It contains the answers to the Review Questions and Multiple Choice Quizzes at the end of the Chapters 2 through 44, as well as the Problems at the end of Chapters 3, 4, 6, 10, 11, 13, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26, 29, 30, 31, 33, 34, 35, 38, 40, 42, and 43. There are approximately 740 review questions, 500 quiz questions, and 500 problems (nearly all of them quantitative) in the text. I have personally answered all of the questions and solved all of the quizzes and problems and have personally recorded the solutions in this booklet. Many of the problems have been tested in class, thus giving me an opportunity to compare my own answers with those developed by the students. Despite my best efforts to avoid errors in this solutions manual, I am sure that errors are present. I would appreciate hearing from those of you who discover these errors, so that I can make the necessary corrections in subsequent editions of the Solutions Manual. Similarly, I would appreciate any suggestions from users of the text itself that might help to make any subsequent editions more accurate, more relevant, and easier to use. My address is: Dr. Mikell P. Groover Department of Industrial and Manufacturing Systems Engineering Lehigh University 200 West Packer Avenue Bethlehem, PA 18015 Office telephone number 610-758-4030. Fax machine number 610-758-4886. E-mail addresses: either Mikell.Groover@Lehigh.edu or mpg0@Lehigh.edu I hope you find the text and this Solutions Manual to be helpful teaching aids in your particular manufacturing course. Mikell P. Groover 3 TABLE OF CONTENTS: Chapter Chapter Title* Page 1. Introduction (No questions or problems) 2. The Nature of Materials 4 3. Mechanical Properties of Materials (P) 7 4. Physical Properties of Materials (P) 18 5. Dimensions, Tolerances, and Surfaces 21 6. Metals (P) 24 7. Ceramics 29 8. Polymers 32 9. Composite Materials 36 10. Fundamentals of Casting (P) 39 11. Metal Casting Processes (P) 49 12. Glassworking 57 13. Shaping Processes for Plastics (P) 60 14. Rubber Processing Technology 70 15. Shaping Processes for Polymer Matrix Composites 73 16. Powder Metallurgy (P) 76 17. Processing of Ceramics and Cermets 84 18. Fundamentals of Metal Forming (P) 87 19. Bulk Deformation Processes (P) 92 20. Sheet Metalworking (P) 112 21. Theory of Metal Machining (P) 122 22. Machining Operations and Machine Tools (P) 134 23. Cutting Tool Technology (P) 142 24. Economic and Product Design Considerations in Machining (P) 153 25. Grinding and Other Abrasive Processes (P) 166 26. Nontraditional Machining and Thermal Cutting Processes (P) 173 27. Heat Treatment of Metals 180 28. Cleaning and Surface Treatments 182 29. Coating and Deposition Processes (P) 184 30. Fundamentals of Welding (P) 190 31. Welding Processes (P) 197 32. Brazing, Soldering, and Adhesive Bonding 207 33. Mechanical Assembly (P) 211 34. Rapid Prototyping (P) 218 35. Processing of Integrated Circuits (P) 222 36. Electronics Assembly and Packaging 230 37. Microfabrication Technologies 233 38. Numerical Control and Industrial Robotics (P) 235 39. Group Technology and Flexible Manufacturing Systems 244 40. Production Lines (P) 246 41. Manufacturing Engineering 253 42. Production Planning and Control (P) 256 43. Quality Control (P) 263 44. Measurement and Inspection 271 *(P) indicates chapters with problem sets. 4 2 THE NATURE OF MATERIALS Review Questions 2.1 The elements listed in the Periodic Table can be divided into three categories. What are these categories and give an example of each? Answer. The three types of elements are metals (e.g., aluminum), nonmetals (e.g., oxygen), and semimetals (e.g., silicon). 2.2 Which elements are the noble metals? Answer. The noble metals are copper, silver, and gold. 2.3 What is the difference between primary and secondary bonding in the structure of materials? Answer. Primary bonding is strong bonding between atoms in a material, for example to form a molecule; while secondary bonding is not as strong and is associated with attraction between molecules in the material. 2.4 Describe how ionic bonding works? Answer. In ionic bonding, atoms of one element give up their outer electron(s) to the atoms of another element to form complete outer shells. 2.5 What is the difference between crystalline and noncrystalline structures in materials? Answer. The atoms in a crystalline structure are located at regular and repeating lattice positions in three dimensions; thus, the crystal structure possesses a long-range order which allows a high packing density. The atoms in a noncrystalline structure are randomly positioned in the material, not possessing any repeating, regular pattern. 2.6 What are some common point defects in a crystal lattice structure? Answer. Some of the common point defects are: (1) vacancy - a missing atom in the lattice structure; (2) ion-pair vacancy (Schottky defect) - a missing pair of ions of opposite charge in a compound; (3) interstitialcy - a distortion in the lattice caused by an extra atom present; and (4) Frenkel defect - an ion is removed from a regular position in the lattice and inserted into an interstitial position not normally occupied by such an ion. 2.7 Define the difference between elastic and plastic deformation in terms of the effect on the crystal lattice structure. Answer. Elastic deformation involves a temporary distortion of the lattice structure that is proportional to the applied stress. Plastic deformation involves a stress of sufficient magnitude to cause a permanent shift in the relative positions of adjacent atoms in the lattice. Plastic deformation generally involves the mechanism of slip - relative movement of atoms on opposite sides of a plane in the lattice. 2.8 How do grain boundaries contribute to the strain hardening phenomenon in metals? Answer. Grain boundaries block the continued movement of dislocations in the metal during straining. As more dislocations become blocked, the metal becomes more difficult to deform; in effect it becomes stronger. 2.9 Identify some materials that have a crystalline structure. 5 Answer. Materials typically possessing a crystalline structure are metals and ceramics other than glass. Some plastics have a partially crystalline structure. 2.10 Identify some materials that possess a noncrystalline structure. Answer. Materials typically having a noncrystalline structure include glass (fused silica), rubber, and certain plastics (specifically, thermosetting plastics). 2.11 What is the basic difference in the solidification (or melting) process between crystalline and noncrystalline structures? Answer. Crystalline structures undergo an abrupt volumetric change as they transform from liquid to solid state and vice versa. This is accompanied by an amount of energy called the heat of fusion that must be added to the material during melting or released during solidification. Noncrystalline materials melt and solidify without the abrupt volumetric change and heat of fusion. Multiple Choice Quiz There are a total of 20 correct answers in the following multiple choice questions (some questions have multiple answers that are correct). To attain a perfect score on the quiz, all correct answers must be given, since each correct answer is worth 1 point. For each question, each omitted answer or wrong answer reduces the score by 1 point, and each additional answer beyond the number of answers required reduces the score by 1 point. Percentage score on the quiz is based on the total number of correct answers. 2.1 The basic structural unit of matter is which one of the following? (a) atom, (b) electron, (c) element, (d) molecule, or (e) nucleus. Answer. (a) 2.2 Approximately how many different elements have been identified (one answer)? (a) 10, (b) 50, (c) 100, (d) 200, or (e) 500. Answer. (c) 2.3 In the Periodic Table, the elements can be divided into which of the following categories (more than one)? (a) ceramics, (b) gases, (c) liquids, (d) metals, (e) nonmetals, (f) polymers, (g) semi-metals, and (h) solids. Answer. (d), (e), and (g). 2.4 The element with the lowest density and smallest atomic weight is which one of the following? (a) aluminum, (b) argon, (c) helium, (d) hydrogen, or (e) magnesium. Answer. (d) 2.5 Which of the following bond types are classified as primary bonds (more than one)? (a) covalent bonding, (b) hydrogen bonding, (c) ionic bonding, (d) metallic bonding, and (e) van der Waals forces. Answer. (a), (c), and (d). 2.6 How many atoms are there in the unit cell of the face- centered cubic (FCC) unit cell (one answer)? (a) 8, (b) 9, (c) 10, (d) 12, or (e) 14. Answer. (e) 2.7 Which of the following are not point defects in a crystal lattice structure (more than one)? (a) edge dislocation, (b) interstitialcy, (c) Schottky defect, or (d) vacancy. 6 Answer. (b), (c), (d) 2.8 Which one of the following crystal structures has the fewest slip directions and therefore the metals with this structure are generally more difficult to deform at room temperature? (a) BCC, (b) FCC, or (c) HCP. Answer. (c) 2.9 Grain boundaries are an example of which one of the following types of crystal structure defects? (a) dislocation, (b) Frenkel defect, (c) line defects, (d) point defects, or (e) surface defects. Answer. (e) 2.10 Twinning is which of the following (more than one)? (a) elastic deformation, (b) mechanism of plastic deformation, (c) more likely at high deformation rates, (d) more likely in metals with HCP structure, (e) slip mechanism, and (f) type of dislocation. Answer. (b), (c), and (d). 2.11 Polymers are characterized by which of the following bonding types (more than one)? (a) adhesive, (b) covalent, (c) hydrogen, (d) ionic, (e) metallic, and (f) van der Waals. Answer. (b) and (f). 7 3 MECHANICAL PROPERTIES OF MATERIALS Review Questions 3.1 What is the dilemma between design and manufacturing in terms of mechanical properties? Answer. To achieve design function and quality, the material must be strong; for ease of manufacturing, the material should not be strong, in general. 3.2 What are the three types of static stresses to which materials are subjected? Answer. tensile, compressive, and shear. 3.3 State Hooke's Law. Answer. Hooke's Law defines the stress-strain relationship for an elastic material: σ = Eε, where E = a constant of proportionality called the modulus of elasticity. 3.4 What is the difference between engineering stress and true stress in a tensile test? Answer. Engineering stress divides the load (force) on the test specimen by the original area; while true stress divides the load by the instantaneous area which decreases as the specimen stretches. 3.5 Define tensile strength of a material. Answer. The tensile strength is the maximum load experienced during the tensile test divided by the original area. 3.6 Define yield strength of a material. Answer. The yield strength is the stress at which the material begins to plastically deform. It is usually measured as the .2% offset value - the point at which the stress-strain for the material intersects a line which is offset from the elastic region of the stress-strain curve by 0.2%. 3.7 Why cannot a direct conversion be made between the ductility measures of elongation and reduction in area using the assumption of constant volume? Answer. Because of necking that occurs in the test specimen. 3.8 What is work hardening? Answer. Strain hardening is the increase in strength that occurs in metals when they are strained. 3.9 In what case does the strength coefficient have the same value as the yield strength? Answer. When the material does not strain harden. 3.10 How does the change in cross-sectional area of a test specimen in a compression test differ from its counterpart in a tensile test specimen? Answer. In a compression test, the specimen cross-sectional are increases as the test progresses; while in a tensile test, the cross-sectional area decreases. 3.11 What is the complicating factor that occurs in a compression test? Answer. Barreling of the test specimen due to friction at the interfaces with the testing machine platens. 8 3.12 Tensile testing is not appropriate for hard brittle materials such as ceramics. What is the test commonly used to determine the strength properties of such materials? Answer. A three-point bending test is commonly used to test the strength of brittle materials. The test provides a measure called the transverse rupture strength for these materials. 3.13 How is the shear modulus of elasticity G related to the tensile modulus of elasticity E, on average? Answer. G = 0.4 E, on average. 3.14 How is shear strength S related to tensile strength TS, on average? Answer. S = 0.7 TS, on average. 3.15 What is hardness and how is it generally tested? Answer. Hardness is defined as the resistance to indentation of a material. It is tested by pressing a hard object (sphere, diamond point) into the test material and measuring the size (depth, area) of the indentation. 3.16 Why are different hardness tests and scales required? Answer. Different hardness tests and scales are required because different materials possess widely differing hardnesses. A test whose measuring range is suited to very hard materials is not sensitive for testing very soft materials. 3.17 Define the recrystallization temperature for a metal. Answer. The recrystallization temperature is the temperature at which a metal recrystallizes (forms new grains) rather than work hardens when deformed. 3.18 Define viscosity of a fluid. Answer. Viscosity is the resistance to flow of a fluid material; the thicker the fluid, the greater the viscosity. 3.19 What is the defining characteristic of a Newtonian fluid? Answer. A Newtonian fluid is one for which viscosity is a constant property at a given temperature. Most liquids (water, oils) are Newtonian fluids. 3.20 What is viscoelasticity, as a material property? Answer. Viscoelasticity refers to the property most commonly exhibited by polymers that defines the strain of the material as a function of stress and temperature over time. It is a combination of viscosity and elasticity. Multiple Choice Quiz There are a total of 18 correct answers in the following multiple choice questions (some questions have multiple answers that are correct). To attain a perfect score on the quiz, all correct answers must be given, since each correct answer is worth 1 point. For each question, each omitted answer or wrong answer reduces the score by 1 point, and each additional answer beyond the number of answers required reduces the score by 1 point. Percentage score on the quiz is based on the total number of correct answers. 3.1 Which one of the following are the three basic types of static stresses to which a material can be subjected (three answers)? (a) compression, (b) hardness, (c) reduction in area, (d) shear, (e) tensile, (f) true stress, and (f) yield. 9 Answer. (a), (d), and (e). 3.2 Which of the following is the correct definition of ultimate tensile strength, as derived from the results of a tensile test on a metal specimen? (a) the stress encountered when the stress-strain curve transforms from elastic to plastic behavior, (b) the maximum load divided by the final area of the specimen, (c) the maximum load divided by the original area of the specimen, or (d) the stress observed when the specimen finally fails. Answer. (c) 3.3 If stress values were measured during a tensile test, which of the following would have the higher value? (a) engineering stress, or (b) true stress. Answer. (b) 3.4 If strain measurements were made during a tensile test, which of the following would have the higher value? (a) engineering stain, or (b) true strain. Answer. (a) 3.5 The plastic region of the stress-strain curve for a metal is characterized by a proportional relationship between stress and strain: (a) true or (b) false. Answer. (b) It is the elastic region that is characterized by a proportional relationship between stress and strain. The plastic region is characterized by a power function - the flow curve. 3.6 Which one of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above. Answer. (c) 3.7 Which one of the following types of stress strain relationship best describes the behavior of most metals at room temperature: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above. Answer. (b) 3.8 Which of the following types of stress strain relationship best describes the behavior of metals at temperatures above their respective recrystallization points: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above. Answer. (a) 3.9 Which one of the following materials has the highest modulus of elasticity? (a) aluminum, (b) diamond, (c) steel, (d) titanium, or (e) tungsten. Answer. (b) 3.10 The shear strength of a metal is usually (a) greater than, or (b) less than its tensile strength. Answer. (b) 3.11 Most hardness tests involve pressing a hard object into the surface of a test specimen and measuring the indentation (or its effect) that results: (a) true or (b) false. Answer. (a) 3.12 Which one of the following materials has the highest hardness? (a) alumina ceramic, (b) gray cast iron, (c) hardened tool steel, (d) high carbon steel, or (e) polystyrene. 10 Answer. (a) 3.13 Viscosity can be defined as the ease with which a fluid flows: (a) true or (b) false. Answer. (b) Viscosity is the resistance to flow. 3.14 Viscoelasticity has features of which of the following more traditional material properties (more than one)? (a) elasticity, (b) plasticity, (c) viscosity. Answer. (a), (b), (c). This answer may require some justification. Viscoelasticity is usually considered to be a property that combines elasticity and viscosity. However, in deforming over time it involves plastic flow (plasticity). Strictly speaking, the shape return feature in viscoelastic behavior violates the definition of plastic flow; however, many materials considered to be viscoelastic do not completely return to their original shape. Problems Strength and Ductility in Tension 3.1 A tensile test uses a test specimen that has a gage length of 50 mm and an area = 200 mm 2 . During the test the specimen yields under a load of 98,000 N. The corresponding gage length = 50.23 mm. This is the 0.2 percent yield point. The maximum load = 168,000 N is reached at a gage length = 64.2 mm. Determine: (a) yield strength Y, (b) modulus of elasticity E, and (c) tensile strength TS. Solution: (a) Y = 98,000/200 = 490 MPa. (b) σ = E e Subtracting the 0.2% offset, e = (50.23 - 50.0)/50.0 - 0.002 = 0.0026 E = σ/e = 490/0.0026 = 188.5 x 10 3 MPa. (c) TS = 168,000/200 = 840 MPa. 3.2 A test specimen in a tensile test has a gage length of 2.0 in and an area = 0.5 in 2 . During the test the specimen yields under a load of 32,000 lb. The corresponding gage length = 2.0083 in. This is the 0.2 percent yield point. The maximum load = 60,000 lb is reached at a gage length = 2.60 in. Determine: (a) yield strength Y, (b) modulus of elasticity E, and (c) tensile strength TS. Solution: (a) Y = 32,000/0.5 = 64,000 lb/in 2 (b) σ = E e Subtracting the 0.2% offset, e = (2.0083 - 2.0)/2.0 - 0.002 = 0.00215 E = σ/e = 64,000/0.00215 = 29.77 x 10 6 lb/in 2 (c) TS = 60,000/0.5 = 120,000 lb/in 2 3.3 In Problem 3.1, (a) determine the percent elongation. (b) If the specimen necked to an area = 92 mm 2 , determine the percent reduction in area. Solution: (a) % elongation = (64.2 - 50)/50 = 14.2/50 = 0.284 = 28.4% (b) % area reduction = (200 - 92)/200 = 0.54 = 54% 3.4 In Problem 3.2, (a) determine the percent elongation. (b) If the specimen necked to an area = 0.25 in 2 , determine the percent reduction in area. Solution: (a) % elongation = (2.60 - 2.0)/2.0 = 0.6/2.0 = 0.3 = 30% (b) % area reduction = (0.5 - 0.25)/0.5 = 0.50 = 50% [...]... Viscosity of Fluids 3.34 Two flat plates, separated by a space of 4 mm, are moving relative to each other at a velocity of 5 m/sec The space between them is occupied by a fluid of unknown viscosity The motion of the plates is resisted by a shear stress of 10 Pa due to the viscosity of the fluid Assuming that the velocity gradient of the fluid is constant, determine the coefficient of viscosity of the... which of the following temperatures marks the beginning of melting? (a) liquidus, of (b) solidus Answer (b) 4.4 Which of the following materials has the highest specific heat? (a) aluminum, (b) concrete, (c) polyethylene, or (d) water Answer (d) 4.5 Copper is generally considered easy to weld, because of its high thermal conductivity: (a) true, or (b) false Answer (b) The high thermal conductivity of. .. atoms of dissolved element replace atoms of the solution element in the lattice structure of the metal An interstitial solid solution is where the dissolved atoms are small and fit into the vacant spaces (the interstices) in the lattice structure of the solvent metal 6.6 What is an intermediate phase in the context of alloys? Answer An intermediate phase is an alloy formed when the solubility limit of. .. the metal is a mixture of solid and liquid 4.3 Describe the melting characteristics of a noncrystalline material such as glass Answer In the heating of a noncrystalline material such as glass, the material begins to soften as temperature increases, finally converting to a liquid at a temperature defined for these materials as the melting point 4.4 Define the specific heat property of a material Answer... melting point 4.4 Define the specific heat property of a material Answer Specific heat is defined as the quantity of heat required to raise the temperature of a unit mass of the material by one degree 4.5 What is the thermal conductivity of a material? Answer Thermal conductivity is the capacity of a material to transfer heat energy through itself by thermal movement only (no mass transfer) 4.6 Define thermal... not, what are some of the other principles involved in hardness testing, and what are the associated tests? Solution: (a) No, the claim is not correct Not all hardness tests are based on the applied load divided by area, but many of them are (b) Some of the other hardness tests and operating principles include: (1) Rockwell hardness test, which measures the depth of indentation of a cone resulting... is reduced so that the rate of diffusion is reduced 4.7 Which of the following pure metals is the best conductor of electricity? (a) aluminum, (b) copper, (c) gold, or (d) silver Answer (d) 4.8 A superconductor is characterized by which of the following (choose one best answer): (a) very low resistivity, (b) zero conductivity, or (c) resistivity properties between those of conductors and semiconductors?... answer beyond the number of answers required reduces the score by 1 point Percentage score on the quiz is based on the total number of correct answers 5.1 A tolerance is which one of the following? (a) clearance between a shaft and a mating hole, (b) measurement error, (c) total permissible variation from a specified dimension, or (d) variation in manufacturing Answer (c) 5.2 Which of the following two... which are based on iron; and nonferrous, which includes all others 6.3 What is the definition of an alloy? Answer An alloy is a metal comprised of two or more elements, at least one of which is metallic 6.4 What is a solid solution in the context of alloys? Answer A solid solution is an alloy in which one of the metallic elements is dissolved in another to form a single phase 6.5 Distinguish between... 0.008 N-s/m2 3.35 Two parallel surfaces, separated by a space of 0.5 in that is occupied by a fluid, are moving relative to each other at a velocity of 25 in/sec The motion is resisted by a shear stress of 0.3 lb/in 2 due to the viscosity of the fluid If the velocity gradient in the space between the surfaces is constant, determine the viscosity of the fluid Solution: Shear rate = (25 in/sec)/(0.5 in) = . 1 SOLUTIONS MANUAL FUNDAMENTALS OF MODERN MANUFACTURING: MATERIALS, PROCESSES, AND SYSTEMS Second Edition MIKELL P. GROOVER Professor of Industrial and Manufacturing Systems. University John Wiley & Sons, Inc., New York 2 PREFACE This is the Solutions Manual for the textbook Fundamentals of Modern Manufacturing: Materials, Processes, and Systems (Second Edition) resisted by a shear stress of 10 Pa due to the viscosity of the fluid. Assuming that the velocity gradient of the fluid is constant, determine the coefficient of viscosity of the fluid. Solution: