ISyE415_Spr24_exam2_answers

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University of Wisconsin, Madison *

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415

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Chemistry

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Jun 24, 2024

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Name: ___________________________________ ISyE 415, Spring 2024, Exam #2 **** Answers & Grading Guidelines **** April 4, 2024 Prof. Charlene A. Yauch The exam has a total of 135 points and represents 16% of your final grade. The number of points for each question is indicated. Please read carefully and write neatly. Be sure to put your name on all pages submitted. You may use a calculator and a 3x5 notecard (both sides). You may write on the back side if more space is needed. Good Luck! Multiple-Choice (6 questions at 5 pts. each, 30 pts. total) Carefully read all options before selecting the best response. Choose multiple responses only if directed to do so. 1. Which of the following processes is the slowest at material removal? A. Milling B. Electrochemical Machining C. Chemical Machining D. Drilling E. Broaching 2. What is an electrode? A. A conductive tool that is used for material removal in electrochemical and electrical discharge machining B. A workholding device that is used for conventional machining processes on a mill, lathe, or grinding machine C. A variable related to how much amperage should be used for an electrical discharge machining process D. A device used to detect electrical activity during a laser cutting process E. None of the above 3. Which of the following describe the applicability of a thermoforming process? (select all that apply) A. It can only be used for thermoplastic materials B. It can only be used for thermoset and elastomer materials C. It is typically used for very small production quantities D. The raw material is a thermoplastic sheet E. It is used to make thin-walled, hollow containers ISyE415, Spring 2024, C. Yauch -1 for each incorrect 1

Name: ___________________________________ 4. For which of the following processes is a customized tool used (one that is unique to the part being produced)? (select all that apply) A. Blow molding B. Drilling C. Grinding D. Compression molding E. Extrusion 5. Which of the following is a common problem associated with drilling? A. Not enough heat generated to perform the operation effectively B. A twist drill does not do a good job of achieving positional accuracy C. Too much cutting fluid interferes with the operation D. It can only be used for through holes E. It leaves a solid core of metal inside the hole 6. Which of the following is NOT an injection molding defect? A. Flash (or flashing) B. Heat affected zone (HAZ) C. Weld lines D. Sink marks E. None of the above; these are all possible injection molding defects Short-Answer Questions (7 questions, 10 pts. each, 70 pts. total) Answer the questions below in the spaces provided (draw figures if they help to explain your answer). 7. What is a rational work element for line balancing? It is the smallest increment of work that can be assigned to a station on the production line. It cannot be practically subdivided any further. -1 to -3 if partially incorrect or vague -3 if no mention of it being impractical to subdivide the element further -5 to -7 if incorrect but response attempted ISyE415, Spring 2024, C. Yauch -1 for each incorrect 2

Name: ___________________________________ 8. State one similarity and one difference between counterboring and countersinking. Possible similarities:  Both are used to make it possible to allow insertion of a bolt or screw such that the head is flush with the surface and not sticking out.  Both can be done before or after the hole is drilled (depending on the type of cutting tool used for the operation). Possible differences:  A counterbore is a stepped lead-in to the hole, and a countersink is a tapered lead-in.  A counterbore can be created with an end mill, and a countersink cannot. 5 pts. each OK to say both are holemaking processes (although this is quite broad) -1 to -2 if partially unclear -1 to -3 if partially incorrect 9. How does solidification occur for a thermoset polymer? The polymer chains in the material form bonds with neighboring chains (which is referred to as cross-linking). Once cross-linking has occurred, it cannot be reversed. OK if cross-linking term used without describing it -1 to -2 if cooling mentioned as part of the process (along with cross-linking) -1 to -2 if partially unclear or vague -5 if whole response vague or incomplete -8 if incorrect but response attempted 10. What is a Heat Affected Zone (HAZ)? It is an area within the material that has been exposed to high temperatures such that the material properties have been altered. The material in the HAZ is often more brittle, making it susceptible to cracking/fracturing. -2 to -3 if partially incorrect -2 if changes in material properties mentioned but no specifics -3 to -4 if missing description of how material properties are impacted -5 to -6 if mostly incorrect -8 if incorrect but response attempted ISyE415, Spring 2024, C. Yauch 3

Name: ___________________________________ 11. For the part shown in the image, along with the additional specifications below, what manufacturing process (or processes) do you think would be used to produce the part? Explain and justify your choice. Material = Aluminum Part Size = 0.75 inch (19.05 mm) diameter x 0.0008 inches (0.0203 mm) thick Note: The part on the right side is enlarged to better show the geometry. Annual Production Volume = 850,000 This part can be created with chemical blanking because it is a very thin sheet of metal and has relatively intricate details in the part geometry. The material is too thin for other processes to be practical (like laser cutting, waterjet cutting, conventional milling, or progressive die punching/ blanking). Chemical blanking can handle the large production volume if it is set up to manufacture parts in a continuous fashion from a coil of raw material. -1 for selecting laser cutting, waterjet cutting, wire EDM (all are feasible to create the geometry if the metal was not so thin) -1 for choosing ECM (because it is similar to chemical machining, but ECM is typically used to create pockets and cavities) -4 for selecting progressive die punching and blanking -4 for selecting EDM (-2 for EDM and wire EDM) -8 for selecting broaching, milling, or any other conventional machining processes -5 if the justification is missing ISyE415, Spring 2024, C. Yauch 4

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