ME 270 HW
How is a blind hole defined in a drilling operation? (a) A hole that does not go all the way through to the other side of the workpiece (b) A hole that can be drilled at any location on the face of the workpiece (c) A hole that can be made to any depth (d) A hole that must be drilled when the operator's view of the drill bit is obstructed
(a) A hole that does not go all the way through to the other side of the workpiece
A finishing cut, as opposed to a roughing cut, is done: (a) At a shallower depth of cut (b) At higher rpm (c) At a smaller feed rate (d) At a deeper depth of cut (e) At lower rpm (f) At a larger feed rate
(a) At a shallower depth of cut (b) At higher rpm (c) At a smaller feed rate
Select which are required for your team project to be approved: (a) It must be novel in some significant way from existing products. (b) It must have a size less than 12"x12"x18" (c) It must have at least 2 mechanical or moving components. (d) The project must utilize snap fits to operate the device or to assemble the device. (e) Your team must be able to start a company with the idea.
(a) It must be novel in some significant way from existing products. (c) It must have at least 2 mechanical or moving components.
DFA techniques can help quantify which of the following? (a) Manufacturing cost (b) Tolerance needed for assembly (c) Ease of assembly (d) Assembly time (e) The best location and method for assembly (f) The skills required for assembly
(a) Manufacturing cost (d) Assembly time
Which method(s) are not Brainstorming tools? (a) Refine, Evaluate, and Improve (b) Post-it-note (c) Scamper (d) SWOT (e) 5 How's (f) Design Tree (g) Reverse Brainstorming
(a) Refine, Evaluate, and Improve (e) 5 How's
To be an effective team member, according to research by Brian Bailey, you should personally work on which of the following: (a) Be inclusive of others - help them feel valued and appreciated for what they contribute. (b) Take turns and don't try and control everything. Create an atmosphere of shared responsibility. (c) When disagreements arise, focus on the evidence you and others base your decision on. (d) Be dressed in the latest fashions clothes. (e) Having a positive attitude is one way to improve the mood, and thus the productivity, of the group. (f) Show up on time (or early) for meetings - when you are late, you communicate this activity is not very important to you. (g) Work hard in order to communicate this project important to you.
(a) Be inclusive of others - help them feel valued and appreciated for what they contribute. (b) Take turns and don't try and control everything. Create an atmosphere of shared responsibility. (c) When disagreements arise, focus on the evidence you and others base your decision on. (e) Having a positive attitude is one way to improve the mood, and thus the productivity, of the group. (f) Show up on time (or early) for meetings - when you are late, you communicate this activity is not very important to you. (g) Work hard in order to communicate this project important to you.
When working with a "Yellow" personality, select the three that are most important: (a) Be understanding of their verbal expressions and playful teasing. (b) Do not try to make them feel guilty. (c) Let them have time to think, and then really show that you are listening to them when they talk. (d) Don't be overly controlling or tell them how to act. (e) Be positive and upbeat. (f) Be accepting and kind, especially to their feelings. (g) Be productive and efficient. (h) Present arguments logically. (i) Don't be aggressive or expect an immediate answer. (j) Do not try to embarrass them or be perceived to attack them personally.
(a) Be understanding of their verbal expressions and playful teasing. (d) Don't be overly controlling or tell them how to act. (e) Be positive and upbeat.
Which of these joining processes does not require melting of the part metal, can be done at 500 C, and is used when joining dissimilar metals or those with poor weldability? (a) Brazing (b) Soldering (c) Stick Welding (d) GMAW Welding
(a) Brazing
A new lathe insert is used on a 100 mm diameter steel workpart, with the lathe going at 300 rpm the insert lasts about 321 min, but at a 100 rpm it lasts for 2010 min. What material could you assume the lathe insert is made out of? (a) Ceramic (b) High Speed Steel (c) Some Refractory alloy (d) Cemented carbide
(a) Ceramic two unknowns (C and n) can use two equations 1) vT^n=C 2)vT^n=C n = ln(v1/v2)/ln(T2/T1) n= 0.6 C=9510 Ceramic
When the rotating end mill deflection is into the workpart, then you are doing... (a) Climb Milling (b) Counter-axis Milling (c) Conventional Milling (d) Cross Milling (e) Counter-axis Milling
(a) Climb Milling
Select any and all processes that work by depositing powder layers and solidifying each layer with a laser. (a) Direct Metal Laser Sintering (DMLS) (b) Stereolithography (SLA) (c) Fused Deposition modeling (FDM) (d) Multi-Jet Printing (MJP) (e) Selective Laser Sintering (SLS) (f) Direct Metal Deposition (DMD)
(a) Direct Metal Laser Sintering (DMLS) (e) Selective Laser Sintering (SLS)
Select all of the following that are methods by which adhesives cure: (a) Evaporation (b) Pressure (c) Heat (d) Radiation (e) Catalyst (f) Electrical current
(a) Evaporation (b) Pressure (c) Heat (d) Radiation (e) Catalyst
Which methods can cast parts that do not require a taper, and can even handle regions with undercut? (a) Expanded polystyrene casting (b) Sand casting (c) Investment casting (d) Shell molding (e) Permanent mold casting
(a) Expanded polystyrene casting (c) Investment casting
Background research on products similar to yours is done after the product is designed. (a) False (b) True
(a) False
Creativity is an innate ability in people. Some can learn it and some can't. (a) False (b) True
(a) False
Rough prototype making is something that occurs only after the Design Process is finished. (a) False (b) True
(a) False
The Product Design Specification (PDS) is put together at the start of a project and should never be modified or changed. (a) False (b) True
(a) False
The difference between a shrink fit and an expansion fit is that in a shrink fit the internal part is cooled to a sufficiently low temperature to reduce its size for assembly, whereas in an expansion fit, the external part is heated sufficiently to increase its size for assembly. (a) False (b) True
(a) False
The reinforcing phase is the matrix within which the secondary phase is embedded. (a) False (b) True
(a) False
Two-plate molds are used to separate the sprue and runners from the parts. (a) False (b) True
(a) False
Under-bending a part ensures that any spring back in the metal will allow it achieve the desired shape. (a) False (b) True
(a) False
When creating inside corners on milled and turned parts, chamfered and sharp edges are preferred over fillet radii. (a) False (b) True
(a) False
Which are considered weaknesses of most 3D Printing methods: (a) Generally not a high tolerance method when compared to other manufacturing methods. (b) Surfaces are generally not smooth and often require post-processing to improve surface finish. (c)They often require a significant amount of training, knowledge, and skill to make parts. (d)It is often time consuming and difficult to change the part design. (e)Although increasing in number, there generally are few material choices. (f)Not a cost effective method for volume production.
(a) Generally not a high tolerance method when compared to other manufacturing methods. (b) Surfaces are generally not smooth and often require post-processing to improve surface finish. (e) Although increasing in number, there generally are few material choices. (f) Not a cost effective method for volume production.
Which of these is used to measure flatness? (a) Interferometry (b) Diffraction grating (c) Gage blocks (d) Profilometer
(a) Interferometry
Which casting method can achieve the best surface finish? (a) Investment casting (b) Permanent casting using special metal dies (c) Shell mold casting (d) Automatic sand casting with hydraulic sand compaction
(a) Investment casting
When Designing a part to be made in the Innovation Studio, what is important: (a) Remove any unnecessary material and make the part as light as possible (use the least material) (b) Increase the part thickness and round corners at stress points (c) Realize that part strength is strongest in the lateral directions and weakest in the vertical direction (d) Realize that holes will be larger than expected and posts will be smaller (e) Choose an orientation that minimizes the need for support material
(a) Remove any unnecessary material and make the part as light as possible (use the least material) (b) Increase the part thickness and round corners at stress points (c) Realize that part strength is strongest in the lateral directions and weakest in the vertical direction (e) Choose an orientation that minimizes the need for support material
Select all that apply. A roughing cut: (a) Removes large amounts of material (b) Is done at low cutting speeds (c) Is done at high cutting speeds (d) Has a small feed and depth of cut (e) Improves the final surface finish (f) Has a large feed and depth of cut
(a) Removes large amounts of material (b) Is done at low cutting speeds (f) Has a large feed and depth of cut
In a sheet metal stamping operation, the scrap part cut out is referred to as a: (a) Slug (b) Medallion (c) Shear-scrap (d) Blank
(a) Slug
Which of the following are true statements? (a) Small design changes can often eliminate the need for cores in sand casting (b) Sharp corners are to be avoided because turbulent flow can erode the mold there (c) Metal casting is easier if the part has an even thickness throughout (d) Designs with holes should always be avoided if possible in sand casting (e) Metal shrinkage without a riser can lead to trapped air in the middle of the cast part (f) Sharp corners can weaken the part due to the columnar grain structure at the corner
(a) Small design changes can often eliminate the need for cores in sand casting (b) Sharp corners are to be avoided because turbulent flow can erode the mold there (c) Metal casting is easier if the part has an even thickness throughout (d) Designs with holes should always be avoided if possible in sand casting (f) Sharp corners can weaken the part due to the columnar grain structure at the corner
In which of the following characteristics do plastic parts often do better than metals: (a) Strength to weight ratio (b) strength (c) resistance to ultraviolet radiation (d) Impact resistance (e) stiffness (f) temperature resistance
(a) Strength to weight ratio (d) Impact resistance
Which are true statements about Structural Foam Molding? (a) The density of material within a part depends heavily on its local temperature during curing. Colder regions will be more dense and hotter regions less dense. (b) SFM can make parts with a higher strength-to-weight ratio than other polymer manufacturing methods. (c) For the material to foam it requires a chemically activated foaming agent. (d) With high pressure injection, production rates can be significantly increased.
(a) The density of material within a part depends heavily on its local temperature during curing. Colder regions will be more dense and hotter regions less dense. (b) SFM can make parts with a higher strength-to-weight ratio than other polymer manufacturing methods.
In a GANTT chart a milestone indicates: (a) The end of one phase of a project (b) A change of direction within a project (c) The beginning of a project (d) The start of a new phase in the project
(a) The end of one phase of a project
At your favorite fast-food restaurant which are variable costs: (a) The water bill (b) Cost of their marketing campaign (c) Rent payment for space (d) Cost of the new oven they just bought (e) The cost of cheese
(a) The water bill (e) The cost of cheese
Which of the following are true statements? (a) Thermoplastics can be repeatedly changed from solid to liquid without chemical change, making them idea for rapid processing. (b) The degree of crystallinity has a greater effect on the stiffness of a polymer than on its melt temperature. (c) Transparent polymers have a degree of crystallinity of zero or near zero. (d) As temperature increases, the density of a polymer also increases. (e) Thermoplastics are the only group of polymers that economically make sense to recycle. (f) As temperature increases the viscosity of a polymer decreases.
(a) Thermoplastics can be repeatedly changed from solid to liquid without chemical change, making them idea for rapid processing. (b) The degree of crystallinity has a greater effect on the stiffness of a polymer than on its melt temperature. (c) Transparent polymers have a degree of crystallinity of zero or near zero. (e) Thermoplastics are the only group of polymers that economically make sense to recycle. (f) As temperature increases the viscosity of a polymer decreases
Which are true about Lubricants for cutting? (a) They should be used at lower cutting speeds than other types of cutting fluids. (b) They dissolve easily in water (c) They reduce the temperature of the cutting tool, but not as much as other cutting fluids. (d) They are comprised almost entirely of hydrocarbons with some additives. (e) They make it easier for cutting chips to not to stick to the cutting tool. (f) They make cutting surfaces smoother.
(a) They should be used at lower cutting speeds than other types of cutting fluids. (c) They reduce the temperature of the cutting tool, but not as much as other cutting fluids. (d) They are comprised almost entirely of hydrocarbons with some additives. (e) They make it easier for cutting chips to not to stick to the cutting tool. (f) They make cutting surfaces smoother.
Benefits of Project Based learning in groups include which of the following: (a) This helps prepare students for the future, since organizations increasingly pursue their goals using teams. (b) Team members can be more motivated to work on the project. (c) It improves your ability to debate and win arguments at all costs. (d) It adds drama to life to make things more interesting. (e) It improves the creativity and the work quality of the project.
(a) This helps prepare students for the future, since organizations increasingly pursue their goals using teams. (b) Team members can be more motivated to work on the project. (e) It improves the creativity and the work quality of the project.
Reaming is used for which of the following: (a) To improve the surface finish inside a hole. (b) To more accurately set the position of a hole. (c) To improve the diameter tolerance of a hole. (d) Is needed before tapping a hole. (e) To start a hole in order to keep a drill bit from ''walking'' across the surface.
(a) To improve the surface finish inside a hole. (c) To improve the diameter tolerance of a hole.
Thermoforming is limited to which plastic types? (a) Viscoelastic materials (b) Elastomer (c) Thermoset (d) Non-Newtonian (e) Pseudoplastic (f) Thermoplastic
(f) Thermoplastic
Amortized Fixed Costs are: (a) Total Capital Costs / (Annual Production Volume x Product Life) (b) Total Variable Costs / (Annual Production Volume) (c) Total Capital Costs / (Annual Production Volume) (d) Total Variable Costs / (Annual Production Volume x Product Life)
(a) Total Capital Costs / (Annual Production Volume x Product Life)
As manufacturing automation increases, costs are generally moved from labor to tooling. (a) True (b) False
(a) True
Composites are difficult to recycle (a) True (b) False
(a) True
During the Design Process as time progresses, design freedom decreases rapidly while the cost of making design changes increases rapidly. (a) True (b) False
(a) True
In a GANTT chart, dependencies, depicted by arrows, are used to illustrate the sequential relationships between tasks. (a) True (b) False
(a) True
Injection molding used high pressure for molding whereas RIM utilizes low pressure. (a) True (b) False
(a) True
It is easier and less expensive to chamfer outside corners compared to adding a radius or round: (a) True (b) False
(a) True
Which of the following statements are true: (a) Whenever possible design parts without the need for mechanical sliders or lifters, as they increase the cost of the die significantly. (b) Some injection molded parts do not require a taper, or a slider for internal undercuts, if the material is sufficiently flexible. (c) Injection molding, like metal casting, works better with parts that have uniform wall thickness. (d) Blow molding can be used to form both thermoplastic and thermosetting materials. (e) If threading is needed in an injection molded part, either use an insert, or design it with very fine threads. (f) Holes should be spaced with a minimum of 1 diameter of solid material between them. (g) High aspect ratio (height/width) features should be aligned with the flow direction of the molten polymer.
(a) Whenever possible design parts without the need for mechanical sliders or lifters, as they increase the cost of the die significantly. (b) Some injection molded parts do not require a taper, or a slider for internal undercuts, if the material is sufficiently flexible. (c) Injection molding, like metal casting, works better with parts that have uniform wall thickness. (f) Holes should be spaced with a minimum of 1 diameter of solid material between them. (g) High aspect ratio (height/width) features should be aligned with the flow direction of the molten polymer.
Quality control is: (a) least variation (b) lowest cost (c) ensuring interchangeability (d) on-target (e) reducing tolerance
(a) least variation (d) on-target
How much powder in SLS is typically thermally damaged and can only be partially reused (a) 10% of total material in the build (b) 10 mm thick shell around the part (c) All excess powder can be reused (d) 80% of total material in the build
(b) 10 mm thick shell around the part
What is a riser? (a) A spacer used underneath a mold to allow better airflow and cooling of the casting (b) A reservoir in the mold that acts as a source of liquid metal to compensate for shrinkage (c) A section of the mold that freezes first to take up any extra metal poured into the casting (d) A tall, skinny section in a casting
(b) A reservoir in the mold that acts as a source of liquid metal to compensate for shrinkage
Which can be melted and cooled repeatedly without degradation? (a) Isoprene (b) ABS (c) Nylon (d) Epoxy (e) PVC (f) Natural rubber
(b) ABS (c) Nylon (e) PVC
If a stamping operation witnesses an increase in burr size, what can be done to correct this (select all correct answers)? (a) Use a softer (more ductile) material (b) Decrease the clearance (c) Use a harder material (d) Decrease the stock thickness (e) Increase the clearance
(b) Decrease the clearance (c) Use a harder material
Select all the processes that do NOT require support structure material. (a) Fused Deposition modeling (FDM) (b) Direct Metal Laser Sintering (DMLS) (c) Multi-Jet Printing (MJP) (d) Stereolithography (SLA) (e) Selective Laser Sintering (SLS)
(b) Direct Metal Laser Sintering (DMLS) (e) Selective Laser Sintering (SLS)
Failures within a weld typically occur in the columnar fusion zone due to embrittlement. (a) True (b) False
(b) False
In interferometry when fringe lines are closer together this indicates the surface is flatter. (a) True (b) False
(b) False
Limit dimension tolerancing provides a nominal value, and an allowable deviance both above and below the nominal value. (a) True (b) False
(b) False
When calculating useful tool life, there is a linear relationship between cutting speed and tool life. (a) True (b) False
(b) False
Your team project will need to cover all the PDS criteria in your final report. (a) True (b) False
(b) False
Since the design engineer only has responsibility for function and performance, he should leave manufacturability issues to the manufacturing engineers on the team. (a) True (b) False.
(b) False.
Which are true of permanent mold casting? (a) Can be used for almost all metals (b) Higher throughput than all expendable mold casting methods (c) Can achieve thinner patterns than expendable mold casting methods (d) The mold melt temperature needs to be lower than the molten metal
(b) Higher throughput than all expendable mold casting methods (c) Can achieve thinner patterns than expendable mold casting methods
Which are examples of "soft" skills: (a) How quickly you understand new information (b) How well you resolve disputes with teammates (c) How well you handle personal failure (d) How well you clearly communicate with teammates (e) The speed at which you can use your calculator
(b) How well you resolve disputes with teammates (c) How well you handle personal failure (d) How well you clearly communicate with teammates
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*HW 10 Questions*
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Select which are primary mental blocks to creativity: (a) Not getting enough sleep or exercise. (b) Inadequate background knowledge and understanding - not spending enough time learning about the problem space this product is trying to solve. (c) Not being innately creative as a child. (d) Not understanding biomimetic practices - how to use biology for inspiration. (e) Fear of criticism by others. (f) A perceptual block where you assume a solution to a problem must look like previous solutions.
(b) Inadequate background knowledge and understanding - not spending enough time learning about the problem space this product is trying to solve. (e) Fear of criticism by others. (f) A perceptual block where you assume a solution to a problem must look like previous solutions.
If the blanking force in a sheet metal operation increases significantly, then the clearance may need to be: (a) Decreased (b) Increased
(b) Increased
Which process has the shortest cycle time? (a) Structural Foam Molding (b) Injection molding (c) Compression Molding (d) Thermoforming (e) Rotomolding (f) Reaction Injection Molding (g) Transfer Molding
(b) Injection molding
In some composite materials, a third ingredient is added to promote the bonding of the primary and secondary phases. This extra ingredient is called: (a) Adhesive (b) Interphase (c) Binder (d) Interface (e) Joiner
(b) Interphase
The race is not always to the swift, but to those who: (a) Are the smartest (b) Keep running (c) Are never afraid (d) Cheat (e) Kill those who get in their way
(b) Keep running
Which of the following are the common attributes of all rapid prototyping processes: (a) Layers comprise powdered polymers. (b) Layers of material are added one at a time to build the solid part from the bottom to the top. (c) Layers comprise photopolymers. (d) Complex 3D shapes are built up from 2D layers.
(b) Layers of material are added one at a time to build the solid part from the bottom to the top. (d) Complex 3D shapes are built up from 2D layers.
What are the advantages of casting? (a) Is highly dimensionally accurate directly out of the mold. (b) Less machining due to being near net shape (c) Has better mechanical properties than machined parts (d) Can create very large parts with internal features (e) Can create complex part geometries
(b) Less machining due to being near net shape (d) Can create very large parts with internal features (e) Can create complex part geometries
Which of the following have water soluble support structures: (a) Selective Laser Sintering (SLS) (b) Multi-Jet Printing (MJP) (c) Fused Deposition modeling (FDM) (d) Direct Metal Deposition (DMD) (e) Stereolithography (SLA) (f) Direct Metal Laser Sintering (DMLS)
(b) Multi-Jet Printing (MJP) (c) Fused Deposition modeling (FDM)
Select all that a group facilitator is responsible for: (a) Cutting off people who've talked too long (b) Recording action items decided upon and recording progress toward their completion (c) Making decisions when there is a tie (d) Assigning action items to people in the group (e) Approving purchases
(b) Recording action items decided upon and recording progress toward their completion
Advantages of metal casting include: (a) Due to surface grain structure, the part is often stronger than the bulk material (b) Scrap metal can often be reused in future castings (c) Parts are near net shaped, which reduces post-processing requirements (d) It is a low energy fabrication process (e) Large parts can be made (f) Metal alloys that do not segregate during cooling can be cast
(b) Scrap metal can often be reused in future castings (c) Parts are near net shaped, which reduces post-processing requirements (e) Large parts can be made (f) Metal alloys that do not segregate during cooling can be cast
A great idea often does not start out as a great idea, but as a decent idea that is iteratively improved until it eventually becomes a great idea. (a) False (b) True
(b) True
A profilometer measures the change in height of a stylus to quantify surface roughness. (a) False (b) True
(b) True
All thermoplastics have the potential to be recycled. (a) False (b) True
(b) True
Arguments are fine during a group meeting as long as people are not acting disrespectfully or unprofessional. (a) False (b) True
(b) True
Carbon-fiber reinforced polymer has a higher strength to weight ratio (in at least one direction) than aluminum. (a) False (b) True
(b) True
Compression molding and transfer molding do not use an extrusion barrel and are primarily used for thermosets and elastomers. (a) False (b) True
(b) True
One of main advantages of rapid prototyping is there is no capital investment in tooling (i.e. molds and dies) (a) False (b) True
(b) True
Which Design Principle revolutionized the photocopy industry? (a) standardize and modularize (b) incorporate ''self-assembly'' or minimize the need for adjustments (c) design for minimum number of parts (d) use of common datum surfaces (e) improve disassembly for repair and servicing (f) assembly in one direction
(b) incorporate ''self-assembly'' or minimize the need for adjustments
Be forgiving of: (a) yourself (b) yourself and others (c) people when they say their sorry (d) no one (e) others, but only after they make it up to you
(b) yourself and others
A single point cutting tool to remove material from the inside of an existing hole: (a) Lapping (b) Drilling (c) Boring (d) Honing
(c) Boring
Variable Costs are: (a) Costs that vary over time (b) Typically upfront costs like tooling, fixture and programming costs (c) Costs incurred every time a part is made (d) Costs that vary a lot because they are only estimates
(c) Costs incurred every time a part is made
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*HW 8 Questions*
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When working with a "Red" personality, select the three most important: (a) Be understanding of their verbal expressions and playful teasing. (b) Don't be aggressive or expect an immediate answer. (c) Do not try to embarrass them or be perceived to attack them personally. (d) Be productive and efficient. (e) Let them have time to think, and then really show that you are listening to them when they talk. (f) Don't be overly controlling or tell them how to act. (g) Be accepting and kind, especially to their feelings. (h) Present arguments logically. (i) Be positive and upbeat. (j) Don't demand perfection.
(c) Do not try to embarrass them or be perceived to attack them personally. (d) Be productive and efficient. (h) Present arguments logically.
The study of how people come up with a new idea is called? (a) The study of creativity (b) Brainstorming (c) Ideation (d) The psychology of inspiration
(c) Ideation
In a turning operation, select all that apply: (a) It is done on a machine called a Mill (b) A rotating cutting tool is moved toward a nonrotating workpiece. (c) It is done on a machine called a Lathe (d) The cutting operation will have circular symmetry. (e) A rotating workpiece is moved toward a nonrotating cutting tool.
(c) It is done on a machine called a Lathe (d) The cutting operation will have circular symmetry. (e) A rotating workpiece is moved toward a nonrotating cutting tool.
Which materials cannot be machined: (a) Foam structures. (b) Expensive materials. (c) Things that are especially brittle such as many ceramics and glass. (d) Materials that have volumes smaller than 1 cubic inch. (e) Parts made by rapid prototype.
(c) Things that are especially brittle such as many ceramics and glass.
Select all the correct reasons as to why SLS machines preheat the build area: (a) To help the part cure faster. (b) So that the process doesn't need to use support structures. (c) To "dry out" the build area. (d) To help the extrudate "bond" to the previous layer. (e) To reduce the build time (f) To help the droplets join with the previous layer.
(c) To "dry out" the build area. (e) To reduce the build time
A fillet weld has a cross sectional shape that is approximately which one of the following? (a) Square (b) Round (c) Triangular (d) Rectangular
(c) Triangular
Concurrent Engineering is: (a) When marketing, design, and manufacturing are done together before costs analysis. (b) When you start production while still finalizing the product design. (c) When the product design is influenced simultaneously by marketing input, material choice, manufacturing process choice, and cost pressures. (d) A quality control process where tolerances are constantly improved.
(c) When the product design is influenced simultaneously by marketing input, material choice, manufacturing process choice, and cost pressures.
If you must use a 1/4 inch diameter mill, then the best surface tolerance and finish would be gotten if all inside vertical corners had a fillet radius with the minimum requirement of: (a) > 0.25 inch (b) < 0.125 inch (c) = 0.25 inch (d) > 0.125 inch (e) = 0.125 inch (f) < 0.25 inch
(d) > 0.125 inch
Which question is important in determining the theoretical minimum number of parts? (a) Can the part be modularized or standardized? (b) Does the part move together and in the same direction as another part? (c) Does the part take 3 seconds to assemble? (d) Does the part move every time and only when another part moves? (e) Does the part need a better tolerance than other parts?
(d) Does the part move every time and only when another part moves?
When working with a "Blue" personality, select the three that are most important: (a) Don't be aggressive or expect an immediate answer. (b) Be positive and upbeat. (c) Be understanding of their verbal expressions and playful teasing. (d) Don't demand perfection. (e) Be accepting and kind, especially to their feelings. (f) Do not try to make them feel guilty. (g) Present arguments logically. (h) Be understanding and appreciative of them. (i) Don't be overly controlling or tell them how to act. (j) Be productive and efficient.
(d) Don't demand perfection. (f) Do not try to make them feel guilty. (h) Be understanding and appreciative of them.
A structured document defining the agreed requirements to be met by all aspects of the enterprise to achieve a successful new model or product: (a) Test Specification (b) Pugh Matrix (c) Project Plan (d) Product Design Specification (PDS).
(d) Product Design Specification (PDS).
What does PDS stand for? (a) Project Delay Series (b) Primary Design Synthesis (c) Product Design Synthesis (d) Product Design Specification.
(d) Product Design Specification.
What joining process uses a tungsten electrode that does not touch the base material? (a) GMAW Welding (b) MIG (c) Wave soldering (d) TIG
(d) TIG
The physical property of plastics that is utilized in spider dies to make tubing is: (a) Pseudo-plastic flow (b) Shear rate thinning (c) Non-Newtonian flow (d) Viscoelasticity
(d) Viscoelasticity
The stiffness of a fiber composites falls to 1/2 when misaligned by approximately: (a) 20 degrees (b) 30 degrees (c) 5 degrees (d) 45 degrees (e) 10 degrees
(e) 10 degrees
Which of the following processes is the least isotropic, especially in the vertical direction? (a) Stereolithography (SLA) (b) Direct Metal Deposition (DMD) (c) Direct Metal Laser Sintering (DMLS) (d) Multi-Jet Printing (MJP) (e) Fused Deposition modeling (FDM) (f) Selective Laser Sintering (SLS)
(e) Fused Deposition modeling (FDM)
Ask lots of questions, even dumb ones; for it is better to look stupid and learn, than to: (a) Not follow your dreams (b) Be immodest (c) Not be successful (d) Say the wrong thing at the wrong time (e) Look smart and remain stupid
(e) Look smart and remain stupid
Which is the correct order of sections in an extruder from the die back to hopper? (a) Extrudate, amorphous flow, granule stock (b) Feed, Compression, Metering (c) Compression, feed, metering (d) Hopper, barrel, die (e) Metering, Compression, Feed
(e) Metering, Compression, Feed
Which can make parts with different color layers of plastics? (a) Vacuum thermoforming (b) Structural Foam molding (c) Blow molding (d) Transfer molding (e) Insert molding (f) Rotomolding (g) Compression molding
(f) Rotomolding
*HW 9 Questions*
*HW 9 Solutions*
Select all the following parts that can be made using an End Mill assuming the work part can be rotated? D E B A C
B A
Identify this part: It's a drill bit with a rounded end
Ball Mill
Identify this part: It's a drill bit with a flat end
Bull Nose
Select all of the following that are not possible to make using a conventional Mill machine? A C D E B
C E
Identify this process: Cutting on the end of a part at an angle
Chamfering
The operator of a CNC machine gets paid $60/hour. It takes him 8 min to load and unload a part (i.e. handling time), and 6 min to change the cutting tool (which has Taylor coefficients of 0.25 and 900 m/min). When he runs the spindle at 900 rpm it finishes a part in 11 min. His cutting tool costs him $95 each and he is able to machine 80 parts before having to replace the tool. He wants to know if he can save money by running the spindle at 1400 rpm. What is the cost per part at 900 rpm and at 1400 rpm? C=vTn→T2T1=(C/v2)1/n(C/v1)1/n=(v1v2)1/n Cost per part at 900 rpm=$ ??? Cost per part at new rpm=$ ???
Cost of part Cc = Co x Tn + Co x Tm + (Co x Tt)/np + Ct/np Where np = number of parts, Co = wage per minute, Tn = time to load and unload, Tt = time to change tool, Tm = time to finish part, Ct = cost of tool. Co = $60/hour = $1/minute Ct = $95 per tool Tn = 7 min Tm = 11 min Tt = 4 min np = 80 Cc at 900 rpm: Cc @ 900 = 1 x (7 + 11 + 4/80) + 95/80 = $19.24 Using T2 = T1 x (v1/v2)^(1/n), we can find T2 when we plug in T1 = 11 x 80, v1 = 900, and v2 = 1100. T2 then will be 394.35 900 x 11 is 9900, and 9900/1100rpm = 9 min per part at 1100 rpm. Therefore 394.35/9 = 43.82, or 43 parts rounded down. We can now use the cost of part equation: Cc @ 1100 = 1 x (7 + 9 + 4/43) + 95/43 = $18.30
Select all of the following that can be made using a ball mill? E D B C A
D
This is a: picture
Dial Indicator?
Identify this process: Turning on the end of a part so that it makes the radius smaller (one large cylinder made into a smaller cylinder)
Facing
Identify this process: Knurling is obvious
Knurling
How long in minutes would it take to fabricate a 4 colored ball 6 cm in diameter using FDM? Assume a layer thickness of 0.3 mm, a width of 0.7 mm, and the extrudate being deposited at a rate of 3.5 cm/sec. The stage movement time is 0.6 sec per layer, and it takes 5 sec to switch between any two materials. Assume the support structure has a volumetric fill ratio of 100%. Time = ??? minutes
Same formula as above
We need to support a cylindrical core with a diameter of 7 cm and a length of 23 cm inside a rectangular cavity with dimensions 20x20x40cm. Assuming the molten metal has a density of 2.6 g/cm3 and the sand core density is 1.1 g/cm3, if each chaplet can support 0.5 N of force, determine the number of chaplets on top and bottom. Number of Top Chaplets = ??? Number of Bottom Chaplets = ???
Solve for bottom chaps: Use Volume*Density = mass (g) pi(8/2)^2 (24) = 1206.37 ---> (1206.37)(0.8) = 965.1 g mass*g (g = 9.81) = Force (965.1)*(9.81) = 9467.63 g ---> convert to kg 9.47 / 0.5 (force each chap can support) = 18.94, round up so bottom needs 19 chaps Solve for top chaps: Use [ Density(fluid) - Density(object) ] * Volume(object) = mass (g) so (2.3 - 0.8)(1206.37) = 1809.56 ---> * 9.81 = 17751.7 g which is 17.75 kg, so 17.75 / 0.5 = 35.5, so 36 chaps for the top
A casting operation is going to make a part with a volume of 900 cm^3 and a surface area of 1070 cm^2. The casting process has been shown to have a Chvorinov constant of 3.8 min/cm^2. You are to design a riser that has a solidification time that is 1.5 times that of the work part and is the shape of a cylinder that has the same height and diameter. What is the riser's height? Height = ??? cm
T = Cm x (V/A)^n where n = 2 T = 3.6 x (900/1030)^2 = 2.75 2.75 x 1.5 = 4.122 Let x = h = diameter Volume = (pi)(x^2/2)(x) Area = 3x^2(pi)(1/2) so 4.122 = 3.6(V/A)^2 Simplifies to 1.0702 = x/6 So x = 6.421 cm
A Lathe rotating at 200 rpm is used to reduce the diameter of an 11 cm long section of stock metal rod from a diameter of 101 mm to 95 mm at a feed rate of 3.2 mm/rev. The force measured at the tool post was 3400 N down and 1800 N pulling the tool toward the workpart. How long does it take to cut the 11 cm length? Time = ??? sec
Time = (pi x length x outerD)/(v x f) length = 110 mm outerD = 101 mm v=200 rpm x pi x 101 mm =63460 mm/minute f=3.2 mm/rev MULTIPLY BY 60 (answer in minutes) answer= 10.31 seconds
How long would it take to fabricate this hollow pyramid using FDM? The square base has a side length of 10 cm and the pyramid is 10 cm tall. The interior cavity is also a pyramid with a square base of 9 cm sides and a height of 9 cm. Assume the extrudate of ABS and support material both have a cross-section of 0.9 mm wide by 0.4 mm tall and is dispensed at a rate of 3.5 cm/sec. The stage takes 0.4 sec to move and it takes 4 sec to switch between materials. The support material has a volumetric fill ratio of 70 %. Volume of a pyramid = (s^2*h)/3. Time = ??? minutes
Time = Total Volume / (feed rate x layer width x layer height) + (Part height/layer height)x(time) find volume of the whole part Vout-(Vin x .30) volumetric fill ratio is 70% so you want to subtract 30%
If the density of a core is 2/11 that of the molten metal, on average what ratio of chaplets on the top versus bottom would you expect (ratio= # on Top / # on bottom)? Ratio = ???
Top = (Dfluid - Dcore)*V Bottom = V*Dcore so [Df - (2/8)Df] / (2/8)*Df ---> (1-(2/8)) / (2/8) = 3
How many of the following are true? (a) Stamping of holes should have diameters greater than the thickness of the metal, except for hard alloys like stainless steel, which can accommodate smaller holes. (b) Holes should be separated by at least the thickness of the metal. (c) What is preferred are holes separated from the edge and each other by twice the metal thickness. (d) Bending very near a stamped pattern creates distortions, but this can be eliminated by removing the material near the pattern that is included in the bend radius. Two One Three Four
Two
A Lathe rotating at 200 rpm is used to reduce the diameter of an 14 cm long section of stock metal rod from a diameter of 100 mm to 98 mm at a feed rate of 3.3 mm/rev. The force measured at the tool post was 3400 N down and 2000 N pulling the tool toward the workpart. What is the specific energy of this material? U = ??? J/mm^3
U = Pc/MRR = (Fc*v)/(vfd) = Fc/(fd) Fc (cutting force down on tool) = 3400N f (feed rate) = 3.3mm/rev d (depth of cut) = (100mm - 98mm)/2 = 1 mm v = 200 x pi x 10 U = 3400/(3.3*1) = 1030.3 Convert to J/mm^3 by dividing by 1000, so final answer U = .10303 J/mm^3
A Lathe rotating at 200 rpm is used to reduce the diameter of an 13 cm long section of stock metal rod from a diameter of 101 mm to 95 mm at a feed rate of 3.1 mm/rev. The force measured at the tool post was 3500 N down and 1800 N pulling the tool toward the workpart. What is the material removal rate? M_RR = ??? cm^3/min
Use MRR (material removal rate) MRR=vfd v=cutting speed (units/min) f=feed (units/rev) d=depth of cut (units) v=200 rpm =(200)(pi)(101/10) =6346 cm/min f=0.31 cm/rev d=((101-95)/2)/10 =0.3 cm Answer = 590.18 cm^3/min
In a turning operation, an aluminum workpart is reduced from a radius of 26 mm to a radius of 24 mm. If the lathe is set at 1500 rpm the tool edge lasts just long enough to cut 50 parts taking 4 minutes for each. If the lathe is slowed to 1/3rd that speed (500 rpm) the tool can now make it through an amazing 1400 parts, but it takes 3 times longer per part. If you then ran the lathe at 900 rpm how many parts could you make before having to replace the cutting edge? Number of Parts = ??? rounded down
VT^n = C (constant) 1: V = 1500 rpm T = 200min 2: V = 500 rpm T = 16800 rpm 3: V = 1200 rpm Unknown T 1500 x 1200^n = 500 x 16800^n (1500/500) = (16800/200)^n n = .2475 Using 2 and 3: 500 x 16800^.2475 = 1200*T^.2475 so (T/16800)^.2475 = 500/1200 so T/16800 = (500/1200)^(1/.2475) = 0.0202 so T = 491.565 min Using 1, we know that 1500 x 4 = 6000 rev for each part. From 3, the total rev is 491.565 x 1200 = 589860. Therefore the # of parts is 589860/6000 = 98.31, or 98 parts.
When working with a "White" personality, select the three that are most important: (a) Let them have time to think, and then really show that you are listening to them when they talk. (b) Be understanding and appreciative of them. (c) Do not try to make them feel guilty. (d) Be accepting and kind, especially to their feelings. (e) Present arguments logically. (f) Don't be aggressive or expect an immediate answer. (g) Be positive and upbeat. (h) Don't be overly controlling or tell them how to act. (i) Don't demand perfection (j) Be productive and efficient.
a) Let them have time to think, and then really show that you are listening to them when they talk. (d) Be accepting and kind, especially to their feelings. (f) Don't be aggressive or expect an immediate answer.
A part to be sandcast has a width of 15 cm, a length of 20 cm and a thickness of 4 cm. To make the part requires 3 cores the shape of straight tubes from one end to the other each with a diameter of 2 cm. These cores will reduce the pour volume but are not to be included as additional surface area: assume negligible heat escapes through the cores. The casting process uses a downsprue with a length of 6 cm, having diameters of 2 cm,2.4 cm, and 3 cm along its length from one end to the other. The casting process uses a cylindrical riser having a height and diameter both of 10 cm. Assuming the Chvorinov coefficient is 3.26 min/cm^2, a. How long does it take to fill the entire mold (assume the runner volume is negligible and don't include the volume of the downsprue)? b. How long does it take just for the part to solidify? Fill time = ??? seconds Time to solidify = ??? minutes
a. Find velocity using sqrt(2gh); where h is the height of the sprue. v = sqrt(2 x 981 x 6) = 108.5 Q = v1A1 = v2A2 Use diameter of the last hole (probably the smallest hole) 108.5 x pi x 1^2 = 340.863 Pouring time is V / Q Volume of the object: (10 x 21 x 4) + (pi x 1^2) - (3 x pi x 1^2 x 21) = 905.973 Volume of riser: pi x 5^2 x 10 = 785.4 Total volume is 905.973 + 785.4 = 1691.37 Therefore pouring time T = Vtotal / Q is 1691.37 / 340.863 = 4.962 seconds b. Solidification time = Cm * (V/A)^n where n = 2 and V = 905.973 We must find the surface area of the object. (10 x 21 x 2) + (10 x 4 x 2) + (2 x pi x 2^2) + (pi x 21 x 4) - (6 x pi x 1^2 ) = 770.177 so T = 3.26 x (905.973 / 770.177)^2 = 4.511 minutes
Which dart thrower is the most precise
b (those closest to the bulls-eye)
