Final Exam W2020

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2/17 The University of Calgary Schulich School of Engineering Winter 2020 Final Examination ENMF 417: Manufacturing and Production Processes Instructor: Dr. Simon Park & Dr. Keekyoung Kim Date: April 29, 2020 Duration: 3 hours (submission within 8:30 am April 29 to 8:30 am on April 30) Instructions: x Note that students are not expected nor required to spend more than three hours on the exam. x This exam is 50% of the total grade. x You must earn a passing grade on the final in order to pass the course x 7KH H[DP LV ³RSHQ ERRN´ DQG ³RSHQ QRWHV´± 1R RWKHU PDWHULDOV VKRXOG EH XVHG including internet. x The use of calculators is permitted. You will need to submit the answers to D2L Dropbox. Please write the answers in the blank white sheets (put your ID on top of the page) and put the page numbers. Please take photos of your answers (and convert into one single PDF file) and upload. Please state assumptions in cases where questions are not clear in lieu for asking TAs or instructors) The Honour Code is an undertaking of the students - individually: that they will not give or receive aid in examinations; that they will not give or receive unpermitted aid that is to be used by the instructor as the basis of grading; The faculty on its part manifests its confidence in the honour of its students by refraining from proctoring examinations and from taking unusual and unreasonable precautions to prevent the forms of dishonesty mentioned above. Examples of conduct that have been regarded as being in violation of the Honour Code include: x Copying from ĂŶŽƚŚĞƌ͛Ɛ examination or allowing another to copy from ŽŶĞ͛Ɛ own exam paper x Unpermitted collaboration ʹ any communication with peers during the exam time x Plagiarism x Revising and resubmitting an exam for regrading, without ŝŶƐƚƌƵĐƚŽƌƐ͛ knowledge and consent x Giving or receiving unpermitted aid on an examination x Representing as ŽŶĞ͛Ɛ own work the work of another The violation honour code includes but not limited to ͞&Ăŝů͟ for the course in which the violation occurred. I understand and abide the Honour code for ENMF417 W2020 Final Exam. Signature _____________________________ Date ___________________ Name ________________________ Indicate how many pages used ______ SP/KK Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

4/17 7 b Which of the following should be avoided in sheet metal processing? a. Overbending the part b. Reduction of thickness c. Springback d. None of the above 8 e Which of the following method is the optimum process to join multiple razor blades? a. Diffusion Bonding b. EDM c. Resistance welding d. Forge welding e. None of the above 9 a The figure to the left shows the stress- VWUDLQ UHODWLRQVKLS± ³²Eµ´ UHSUHVHQW s which kind of relationship? a. Linear Elastic/Perfectly Plastic b. Linear Elastic/Plastic c. Rigid-Perfectly Plastic d. Rigid/Linear hardening e. None of the above 10 c ,Q WKH ILJXUH DERYH ²4±¶µ· ³²Gµ´ UHSUHVHQW s what kind of relationship? a. Linear Elastic/Perfectly Plastic b. Linear Elastic/Plastic c. Rigid-Perfectly Plastic d. Rigid/Linear hardening e. None of the above 11 a In general, which of the following cutting conditions has the greatest effect on chatter in milling operations? a. Depth of cut b. Feed rates c. Use of lubricant d. All of the above equally affect chatter Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455 * linear elastic plastic Elastic / perfectly - plastic ridged linear ridged - perfly - plastic hardening cutting speed ? b ?

5/17 12 c For a tension test of a material, the area under the entire curve is a measure of its ____? a. Elasticity b. Resilience c. Toughness d. Ductility 13 c Which of the following factors is not a concern for machinability of materials? a. Surface integrity b. Tool life c. Friction d. The level of difficulty in chip control 14 d In evaporation mold casting, the pattern is made of what? a. Wood b. Metal c. Plaster d. Polystyrene e. None of the above 15 b Redundant work in any bulk deformation process is a function of which of the following factors? a. Friction b. Non-uniform deformation c. Residual stress d. None of the above 16 c What is the maximum draft possible in rolling when the roller radius is 0.1 m, the friction coefficient is 0.1? a. 0.1 m b. 0.001 m c. 0.01 m d. None of the above 17 b Which of the following is not an example of defects associated with rolling? a. Wavy edges b. Chevron cracks c. Alligatoring d. Edge cracks 18 c Which of the following phase is _______ when temperature is 600 o C and carbon contents of 0.5 % in the Iron-carbon phase diagram? a. Austenite b. Ferrite c. Perlite d. Cementite e. None of the above Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455 0 i ✓ probably ? - potentially ? 0,12 0 . I = 0 . 00 I ✓ 0 =

7/17 25 a Selective laser sintering or SLS is characterized as what type of process: a. An additive process b. A subtractive process c. A casting process d. None of the above 26 b A misrun is one of the defects in casting, which occurs due to ____? a. Globules of metal becoming entrapped in the casting b. Premature solidification c. Micro porosity d. Metal not properly poured into the down sprue 27 b How would you manufacture Jacuzzi bathtubs (qty. 500)? a. Rapid prototyping b. Thermoforming c. Injection molding d. None of the above 28 b Which of the following processes are used to provide the thin coatings on the surface of coated carbide inserts used in machining processes: I. Chemical vapour deposition II. Electroplating III. Pressing and Sintering IV. Physical vapour deposition V. Spray painting a. I, II b. I, V c. I, IV d. II, III, IV e. All of the above 29 b Which of the following process is the best way to generate a keyway on a hub used in airplane rotors? a. Grinding b. Broaching c. Reaming d. None of the above 30 d :KDW¶V WKH EHVW ZD y to manufacture copper electrical wires? a. Extrusion b. Progressive die forging c. Rolling d. None of the above 31 b Which process makes parts with the least favourable metallurgical property? a. Grinding b. Casting c. Machining d. Forging Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

8/17 32 b Holes made by a drilling process are often finished by what operation? a. Grinding b. Reaming c. Shaping d. Spinning 33 d Which of the followings is not a factor affecting sheet metal deformation? a. Elongation b. Anisotropy c. Residual stress d. None of the above 34 b Which of the following options is not related to metrology? a. AFM b. XRD c. Micrometer d. None of the above 35 a Which of the following abrasive materials is most appropriate for general purpose grinding of non-ferrous metals such as aluminum? a. Silicon carbide b. Cubic boron nitride c. Diamond d. Aluminum oxide e. All of the above 36 e Which of the following does not describe Industry 4.0? a. Internet b. IoT c. Cloud d. AI e. None of the above 37 a How would you manufacture artificial diamonds? a. PVD b. Electron beam c. Carburizing d. All of the above e. None of the above 38 C How would you manufacture professional golf clubs (qty. 10,000)? a. Investment casting b. Sand casting c. Progressive die forging d. None of the above Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

10/17 PART II. Short Answer Problems (25 points) Q1 [4 pts]. The following structure has been sand-casted. a. Describe hot tearing. Explain with the aid of appropriate sketches, the events leading to the problem. b. Come up with a better design to minimize such problems. Q2 [6 pts]. Draw the stress-strain curve and Calculate the specific energy of a. Perfectly elastic material. b. Rigid and perfectly plastic material. Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

11/17 Q3 [2 pts]. In the Supreme Skills Video, there were two teams competed for joining two different metal bars. One team used brazing and the other team used screws. Please discuss which team has won for tensile pull tests and discuss the reasoning. Q4 [4 pts]. Discuss the pros and cons associated with manufacturing following items using different manufacturing processes. Casting vs. stamping a sheet-metal frying pan (2 of each) Pros Cons Casting Able to hold better heat One piece More weights Expensive Longer time Stamping Cheap Can be coated (Teflon) lighter Poor heat conduction Handles ± need to add Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

13/17 PART III. Calculation Problems (30 points) Q6 [8 pts]. In a stretch forming, a thin piece of sheet metal, whose thickness is 3 mm, with a width of 2 m and the length of 3 m, is stretched with a force F until the angle Į is 30 q as shown in the figure below. The 4340 Steel material exhibits a true stress-true strain behaviour. Find the work done if frictional and redundant work contributes to 30%. Find the final length Lf = a + b A = 2 / cos 30 = 2.309 Defl = 1.1547 B = sqrt (1 + 1.1547^2) = 1.527 A+B = 3.837 Eta = ln (lf/l0) = ln (3.837/3) = 0.246 Work = u * volume U = K * eta^(n+1)/n+1 = 171 MPa V = 0.003 * 2* 3 = 0.018 m^3 Work = 3.078 MN*m 2 m F ± D Material Yield Stress (MPa) Ultimate Stress (MPa) Elastic Modulus (MPa) K (MPa) n 1020 Steel 300 420 207000 530 0.26 4340 Steel 400 600 207000 640 0.15 2024 Al Alloy 350 400 72000 690 0.16 304 Stainless Steel 210 550 185000 1275 0.45 70/30 Brass 75 300 110000 900 0.49 Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

14/17 Q7 [10 pts]. In an effort to reduce the weight of the sprocket/shaft assembly, it is proposed that an integrated design could be manufactured by cold forging (upsetting) an aluminum shaft (shown in the upper view) to form the finished shaft and sprocket blank (shown in the lower diagram) followed by machining of the sprocket teeth in the enlarged disc. The lower view shows a cross section of the forging (upsetting) dies and the upset shaft. The dimensions of the workpiece are as follows: Initial length: 180 mm Initial diameter: 20 mm The enlarged disc should have a final diameter of 40 mm and a thickness of 8 mm. The proposed workpiece is 2024 Aluminum alloy. The following question assumes that the process proposed is viable. Assumptions: frictionless and the final shaft diameter is the same. State all your assumptions a. How far do the dies need to move (in mm) during a complete loading stroke? b. What is the true strain imposed upon the workpiece? c. What is the flow stress at the end of the deformation? d. What force would be required to complete the deformation? sprocket Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

16/17 Q9 [6 pts]. Assume that in orthogonal cutting the rake angle is 30º, the modulus of elasticity of material is 210GPa, cutting velocity of 3 m/min, and the coefficient of friction is 0.3. Determine the percentage change in deformed chip thickness when the friction is tripled. (Hint: Use the theoretical shear angle formula) Alpha = 30 deg Mu = 0.3 = tan beta Beta = 17 deg Rc = h/hc = sin phi / cos (phi-alphar) Hc2/hc1 = cos (phi2-alpha2) sin phi1 / cos (phi1 ± alpha1) sin phi 2 Phi1 = pi/4 ± (beta1 ± alpha)/2 = 51.5 deg If friction doubled beta2 = 42 deg Phi2 = 39 deg 6XEVWLWXWH« \RX ILQG WKDW Hc2/hc1 = cos (phi2-alpha2) sin phi1 / cos (phi1 ± alpha1) sin phi 2 = 1.32 32% increase ************** SSP/KK Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455

17/17 s s s A F W c c h h r a v u a F F P E tan c s bh A I sin ) cos( cos r c r s V V D I D ² c f c t r a c s F F F F I I D E I sin cos ) cos( ² ² ³ ) cos( ) sin( ) cos( ) cos( r a c c r a s r a t bh F F D E I I D E W D E ² ³ ² ² ; r c r c c r r D D I sin 1 cos tan 1 ² ² ) cos( sin r c c c c h h L D I I ² t f r a F F ² ) tan( D E ) ( r s s s s s T T C MRR V F P ² V r V c c c u u V F P u MRR P P V F P u s t tot ³ Theoretical shear angle (Min. Energy Principle) 2 ) ( 4 r a c D E S I ² ² nN f c ) sin( I c h S 2 60 n : t : I q t t C V C T ² -p Rt I H 2 2 / 1 ² ³ kd Y Y i l a d c L D p q K S 128 4 Plane Strain (Von Mises): ' 15 . 1 3 2 3 1 Y y y ² V V V V ¸ ¹ · ¨ © § ³ | h a Y p avg P 1 ' ; ¸ ¹ · ¨ © § ² h x a Y P ) ( 2 exp ' P ; Rolling: R h h f 2 0 P ² Extrusion f A A R 0 ; ¸ ¸ ¹ · ¨ ¨ © § f A A k u p 0 ln ; > @ 1 tan 1 cot ² ¸ ¸ ¹ · ¨ ¨ © § ³ D P P D R Y p Drawing » » ¼ º « « ¬ ª ¸ ¸ ¹ · ¨ ¨ © § ² ¸ ¸ ¹ · ¨ ¨ © § ³ D P P D V cot 0 1 tan 1 A A Y f d ; ¸ ¸ ¹ · ¨ ¨ © § f f A A YA F 0 ln Downloaded by Morgan Bresee (morgiebresee@gmail.com) lOMoARcPSD|4497455