Fundamentals of Manufacturing. EXAM 2 Dec 6, 2008 Name Open Book, (~75 min.) You are allowed a 5x7 card, a calculator and a pencil. Show all work.

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1 MEEN Fundamentals of Manufacturing EXAM 2 Dec 6, 2008 Name Open Book, (~75 min.) You are allowed a 5x7 card, a calculator and a pencil. Show all work. Select the best definition, some may be used more than once. (1 point ea, 16 tot.) 1. MEMS 2. Lithography 3. Tertiary Industry 4. Selective Laser sintering 5. Vacuum bagging 6. Draft 7. Turning 8. Injection molding 9. Stereolithography 10. Continuous chip 11. Matched die molding 12. BMC 13. Three dimensional printing 14. Milling 15. Discontinuous chip 16. Grinding composites A. A stationary tool is moved over a stationary workpiece. B. Printing an isometric view of an object. C. Where two mold halves close during a molding process to form a finished composite part. D. A polymer/fiber molding compound that is mixed before-hand and used as a charge. E. A reservoir used as a source of liquid metal to compensate for shrinkage. F. A process where molten plastic is forced through a cross-section die onto a belt. G. A cutting tool is used to remove material from a rotating workpiece. H. A method of making sure you have enough soldiers to fight a war. I. Printing process used to transfer copies of a mask pattern onto the surface of silicon or other solid material J. The service sector of the economy. K. The slight tapering of mold walls so that a molded part can be removed. Not usually needed for rubber parts. L. When a thick shell of plaster is slapped around a pattern. M. Using a laser to solidify a liquid polymer into a specified shape. N. When a ductile material is cut at high speeds, this is formed. O. A form of machining typically only performed for cosmetic purposes, in conjunction with a dust collector. P. A method of fabricating plastic or metal parts using a laser to heat and fuse powders one layer at a time. Q. Microelectromechanical systems R. A coated fabric or film that enables good release of a plastic or composite part. S. None of the above. Polymer Fabrication Short Answers & Multiple Choice (3 points each, 9 total points): 16. A two-part epoxy is mixed and poured into a mold. The mix ratio is off by about 15%, briefly tell what might happen. 1

2 17. Which of the following defects or problems is associated with injection molding (three correct answers): (a) bambooing, (e) melt fracture, (b) die swell, (f) short shots, or (c) drag flow, (g) sink marks? (d) flash, 18. Which 3 of the following processes are associated with the production of plastic sheet & film? (a) blown-film extrusion process, (e) spinning, (b) calendering, (f) thermoforming, (c) chill-roll extrusion, (g) transfer molding? (d) doctor blade method, Composites Fabrication (3 points each, 3 problems, 9 points) 19. In filament winding, when the continuous filament is wound around the cylindrical mandrel at a helix angle close to 90, it is called which of the following (one best answer): a) bi-axial winding, b) helical winding, c) hoop winding, d) perpendicular winding, e) polar winding, or f) radial winding? 20. A molding operation that uses sheet-molding compound (SMC) is a form of which one below? (a) compression molding, (d) open mold processing, (b) contact molding, (e) pultrusion, or (c) injection molding, (f) transfer molding? 21. Filament winding involves the use of which two of the following fiber reinforcements: a) continuous filaments, d) prepreg fiber, b) fabrics, e) short fibers, or c) mats, f) woven rovings? Machining (3 points each, 3 problems, 9 points) 22. Which one of the following metals would usually have the lowest unit horsepower in a machining operation: a) aluminum, b) brass, c) cast iron, or d) steel? 23. Name three types of machining operations and write a few words about each. 24. According to the Merchant equation, an increase in rake angle would have which of the following results, all other factors remaining the same (two best answers): a) decrease in friction angle, d) increase in cutting temperature, or b) decrease in power requirements, e) increase in shear plane angle? c) decrease in shear plane angle, 2

3 Rapid Prototyping (3 points each, 6 problems, 20 points) 25. Which of the following RP technologies uses powders as the starting material (two correct answers): (a) ballistic particle manufacturing, (b) fused deposition modeling, (c) selective laser sintering, (d) solid ground curing, and (e) three dimensional printing? 26. Give 4 reasons why rapid prototyping is increasing in popularity. 27. Which of the following are problems with the current material addition rapid prototyping technologies (three best answers): (a) inability of the designer to design the part, (b) inability to convert a solid part into layers, (c) limited material variety, (d) part accuracy, (e) part shrinkage, and (f) poor machinability of the starting material?: 28. What are 3 types of starting materials used for rapid prototyping? 29. (8 points) Using Rapid Prototyping: A) State your final project that you made for this course, and list 3 RP methods that could be used to at least simulate their shape. B) Discuss their pros & cons, and discuss which is the best to also provide the most functionality. 3

4 MEMS and Microfabrication (3 points each, 5 problems, 15 points) 30. Microsystem technology includes which of the following (three best answers): (a) LIGA technology, (b) microelectromechanical systems, (c) micromachines, (d) nanotechnology, (e) precision engineering? 31. List 6 applications of micro-sensors or other MEMS devices 32. In the LIGA process, the letters LIGA stand for which one of the following: (a) let it go already, (b) little grinding apparatus, (c) lithographic applications, (d) lithography, electrodeposition, and plastic molding, (e) lithography, grinding, and alteration? 33. Why is silicon a desirable work material in microsystem technology? 34. The polymer used to make compact discs (CDs) and digital versatile discs (DVDs) is which one of the following: (a) amino resin, (b) epoxy resin, (c) polyamides, (d) polycarbonate, (e) polyethylene, or (f) polypropylene? 4

5 Laboratory Knowledge (6 points) 35. (6) Give the topic or title of a lab that we should have conducted, then discuss what we should do in the lab to learn about the manufacturing process. Give some detail. Projects (Give some detail for each answer, 12 points) 36. (3) Discuss the differences between the two pool cue stick projects. 37. (3) How could the mini surfboard been fabricated better? 38. (3) Discuss how the skateboard could have been fabricated in a faster and better way. 39. (3) Discuss the similarities and differences between the fabrication of the key chains and the yoyo s. ********************************************************************** 5

6 Each will receive 4 points credit if this survey is filled out (4) Self-Evaluation of Learning, MEEN 3349 Fall 2008, Exam 2 c.) An ability to design a system, component, or process to meet desired ends. h.) Broad education necessary to understand the impact of engineering solutions in global society. j.) A knowledge of contemporary issues. Check the box that you most agree with. Strongly agree Agree Neutral Disagree Strongly dis-agree I can select or design a manufacturing process to fabricate a ladder. I understand the basic machining processes and could suggest the best for a specific part. I understand the basic rapid prototyping processes and could select the best for a design. My knowledge of manufacturing methods helps me to understand their effect on our global society. I understand why certain laborintensive parts are manufactured in other countries. I understand how contemporary manufacturing methods such as Rapid Prototyping and Microsystems (MEMS) fabrication can impact our society. I understand how MEMS fabrication techniques can reduce the size and cost of a hand-held breath analyzer. I know the difference between turning, milling, and drilling. I could machine a basic mold and cast a plastic part. Ways to improve the course/ Comments 6