DML Exam Review with Complete Solution

which of the following are true: a. sheetmetal refers to workpieces with a high ratio of surface area to thickness b. sheets are defined as <= 1/4" in thickness c. plates are defined as >= 1/4 " in thickness d. pulling, pushing, and stretching are the most common sheetmetal operations - ANSWER A, B, and C The Lab has the following sheetmetal capabilities: A. shear B. Brake (bending machine) C. punch press for creating holes D. deep drawing/ stretch forming - ANSWER A, B, C what is the structural benefit of bending sheetmetal edges/ flanges? - ANSWER makes it more rigid Which of the following are key element to decision matrices? A. clearly defined & weighted objectives B. Justified magnitude assignments with traceable supporting data C. always try to use linear score assignments D. highest scoring concept wins - ANSWER all of the above why are separate evaluation matrices created for separate functional subunits of a design? - ANSWER pick the best subunits because we can combine them T/ F manufacturing time is an example of a qualitative assessment? - ANSWER False What are (4) the things that can cause calipers to measure inaccurately? - ANSWER failure to zero the calipers before use debris, chips, or burrs failure to hold the jaws perpendicular to the surface inadequate or excessive closing pressure T/ F Your group must have a fully dimensioned, appropriately toleranced part drawing for each part manufactured in the lab - ANSWER TRUE T/ F If anyone in your group doesn't understand how each part of your design works, that person will be instructed to stop working until they do - ANSWER TRUE What should do if anyone in your group makes excuses for not completing their work on time or at an acceptable quality: A. accept effort, not excuses and isntrcut the person to redo the assignment B. make a record of tehir work quality or tardiness on your meeting documentation C. if the problem isnt resolved within 48 hr., get Mike involved because youre here to learn D. wait to confront the problem in hopes that doing so may avoid conflict - ANSWER A, B, C T/ F Purchase orders must be submitted next week before using ANY raw materials in the lab - ANSWER TRUE T/ F ECN's are used to formally track design changes and corrections through the project prototyping and life- cycle phase - ANSWER TRUE Groups which care about their success on the course project will read the Project Tips posted on the website and do which of the following: A. review their weekly schedule and plan their individual work assignments B. review part drawings in office hours with a TA to be prepared to make the parts in lab C. complete paperwork outside their formal lab block D. print working copies of non- OTS part drawings for reference during lab E. use 80/20 wisely by selecting pre- cut pieces before cutting longer pieces to length; and only cutting the shortest over-size pieces to the necessary lengths F. bring 1:1 scale printed and trimmed sheetmetal templates to lab to expedite part fabrication G. prepare for the Tapped Hole Quiz H. have a backup plan in case a machine their group needs is being used I. always wait for their TA to answer questions - ANSWER A- H Use OTS/ custom part - ANSWER OTS use larger/ smaller feature tolerances - ANSWER larger use coarse/ finer surface finish specifications - ANSWER coarser use fewer/ more finished surfaces - ANSWER fewer use fewer/ more dimension datums - ANSWER fewer use stronger/ weaker material - ANSWER weaker use tapped/ thru - bolted holes - ANSWER thru- bolted use blind/ thru holes when reasonable - ANSWER thru use cone- bottomed/ flat- bottomed holes - ANSWER cone- bottomed use arbitrary/ nominal part dimensions - ANSWER nominal design parts to be larger/ smaller - ANSWER smaller design parts for max/ min raw stock removal - ANSWER min design parts to use larger/ smaller cutting tools - ANSWER larger design parts fewer/ more fillets - ANSWER fewer design around custom/ standard cutting sizes - ANSWER standard avoid/ use mirror image parts - ANSWER avoid make acceptable/ great detailed part drawings - ANSWER great you must come to lab each week with long ____, proper ____, and printed equipment ______ ________ - ANSWER pants, shoes, safety sheets never leave the ______ ______ in the lathe chuck - ANSWER chuck key never reach over the rotating ______ on the lathe for any reason because of the dangerously protruding ______ ______ - ANSWER chuck, chuck jaws always _____ and ______ the milling machine spindles before changing tools over the plastic _____ _______ - ANSWER raise, lock, table cover Always check the milling machines and lathes are in _____ range before turning them on - ANSWER high Always adjust the _____ _____ with the mills, lathes, and drill presses running - ANSWER spindle speed Never pull _____ off the machines using your hands; use a rag instead - ANSWER chips always engage the workpiece ______ to avoid chipping the fragile cutting inserts/ edges - ANSWER gently always wear _____ when working with sheetmetal, except when using ____ _____, such as bandsaws, drill presses, grinders, and sanders - ANSWER gloves, power tools never cut any material except _____ on the marvel bandsaw - ANSWER aluminum always take time to _____ each workpiece after cutting to remove the sharp edges which can injure a teammate or TA - ANSWER debur using a(n) ______ arc to heat separate pieces of _____ material to be joined to a temp high enough to cause _____ and coalescing - ANSWER electric, similar, melting List the three most common types of electric arc welding - ANSWER SMAW, GMAW, GTAW T/ F Dissimilar metals can be joined using the arc welding process if the proper filler metal is used - ANSWER FALSE T/F The electrode used when MIG welding process if consumed as the weld is made - ANSWER TRUE What is the purpose of flux or shielding gas? - ANSWER to prevent rapid oxidation by preventing oxygen from coming into contact with the molten metal pool list 3 advantages of MIG welding - ANSWER easiest to learn fastest economical list 3 advantages of TIG welding - ANSWER strongest welds possible no post weld clamp can weld virtually any metal that is conductive whats the primary difference between MIG and TIG welding? - ANSWER MIG welding automatically feeds the filler wire into the weld pool; TIG welding uses a tungsten electrode to conduct the electricity and provide the heat source, and the actual filler wire is fed manually into the molten pool T/ F Most lab motor fasteners are metric and should be obtained by telling the TAs what size you need - ANSWER TRUE T/ F If any fasteners do not freely thread together by hand, you should stop and ask a ta before damaging expensive components - ANSWER TRUE T/ F when connecting the control box to the motors for the first time you must ask a TA for help - ANSWER TRUE T/ F When wiring the control box each subsequent time you must turn off the main power before changing any wiring to prevent electrical damage - ANSWER TRUE T/ F Before changing tools in the lathe the spindle must first be raised to an locked in its uppermost position - ANSWER FALSE T/ F The lathe chuck key should be removed from the chuck after clamping the tool securely - ANSWER FALSE T/ F Before changing the lathe between HI and LOW range you must ask for TA help - ANSWER FALSE T/ F Lathe, mill and drill press spindle speeds must be adjusted while the machines are OFF - ANSWER FAlSE T/ F Safety glasses must be worn any time you are in the shop, including during TA hours - ANSWER TRUE List 4 features CNC machines possess that allow increased productivity - ANSWER automatic tool change electronic probing high pressure coolant stiffer structures and more powerful motors list 4 drawbacks of cnc machining centers - ANSWER debugging more expensive require more frequent and more costly maintenance often slower for making one simple part/ feature list and define the two common methods of programming CNC machines - ANSWER conversational programing CAM Explain the two types of parts CNC machines are better suited for over manual machines - ANSWER complex parts requiring multiple axes of simultaneous motion mass production for what type of parts are manual machines a better choice than CNC machines - ANSWER simple, low quantity T/ F CNC machines always require less time to make a part than manual machines - ANSWER FALSE Which of the following machines in the lab could be automated via CNC technology? 1. milling machine 2. lathe 3. welder 4. sheetmetal shear 5. sheetmetal brake 6. sheetmetal punch - ANSWER all of the above List the easiest mistake to make when changing tools on milling machines - ANSWER raise lock and spindle list 3 things you should check before/ when turning on milling machines - ANSWER tool clearance speed range rotation direction list the most important rule when using manual lathes - ANSWER never leave chuck key in chuck T/F all sheetmetal parts are razor sharp after shearing and should therefore be deburred immediately after cutting - ANSWER TRUE T/ F This is the point in the semester when a serious accident is most likely to occur because of how easy it is to drop our guard and forget how dangerous the equipment can be if not used properly - ANSWER TRUE What are the principal benefits of allocating individual member tasks via a works schedule? A. it allows the team to honestly decide if it possesses adequate resources to complete the project within the allotted timeframe B. it allows the team to prepare for each lab session and work more efficiently C. it facilitates individual accountability D. all of the above - ANSWER D What is the equation governing maximum peripheral tool velocity as a function of tool size? - ANSWER V= pi x D x N What is the purpose and benefit of peck drilling? - ANSWER peck drilling help chips evacuate so they dont collect inside the hole and cause the drill bit overheat, seize and break What is the limiting factor for how fast a drill or endmill can rotate in a particular material? A. maximum speed of machine spindle B. type of taper/ collet used to hold tool C. number of flutes on the cutter D. heat generated in the cutting zone - ANSWER D What is the limiting factor for how fast a drill or endmill can feed thru any material? A. maximum speed of machine spindle B. operator courage C. phase of the moon at that particular hour D. size / strength of cutting edges/ lips - ANSWER D what is the limiting factor for how deep to cut (per pass) with an endmill in a particular material (assuming sufficient flute length)? - ANSWER cutting tool/ workpiece/ machine stiffness (which must resist the cutting forces and subsequent