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Team INASAD
Members: Jose Medina Joseph
LeoneAndrew Merk Alex
SandersMichael Fox
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Midterm recapFinal design
modificationsFinal designSubsystem overviewEngineering analysisPrototyping modifications
Agenda:
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Project TopicFluorescent Light Changing System
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Problem StatementHundreds to thousands of fluorescent light bulbs in an
average building. Changing bulbs is dangerous and time consuming
To improve this process, an instrument which from the ground could:
grasp the lighttwist the bulb to unhook itremove it install a new light
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GoalThe overall goal of this project is to create a
tool that:
Simplifies the removing and installation of fluorescent light bulbs
Makes the overall task safer
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Customer NeedsOperators Needs:
Minimize the use of a ladderOperable by one person
minimal physical and mental effortDecrease the time to change a bulb by hand Reliable and easily maintained
Manager or Owners’ Needs Limits number of employees and time needed to perform
the task Decrease injuriesCost offset by decreased number of people and hours
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Midterm Concept
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Final Design
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Post Midterm ModificationsTilting mechanism
Safety Shield
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Bulb Collecting SubsystemInstallation/Removal System
Consists of: 2 U-shaped areas for bulb to fit
1 for bulb removal 1 for bulb installation
Using a cam, spring and pull cable the system will rotate 90 degrees
Simplifies removal and installation process
Improves alignment
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Bulb Rotating SubsystemRotation System
Consists of: Crescent shaped base Spring Pull cables Activation gripping handle
Suction Cup Gripping SystemConsists of:
3 suction cups for each sled Suction cups attached to a crescent
shaped base
Force needed to rotate a light bulb into removal position is 2.8 lbs.
Each suction cup can with stand an average force for 1.7 lbs
3 suction cups = 5.1 lbs of force
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Bulb Gripping Subsystem
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Safety SubsystemMaterial
Thin Polycarbonate
Flexible See through
Polycarbonate helps balance the tool during operations
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Trapezoidal Bowing System4 adjustable bars for
stability2, ¼ circle adjustable disks
15°-90° adjustment1 Lever adjustment bar
Bowing Subsystem
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Tripod baseRack and Pinion
height adjustmentAllows for large and
precise maneuveringHand crank or power
drill adjustable
Base/Raising and Lowering Subsystem
Normalizing SubsystemLeveling mounts
normalize tool on uneven surfaces
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Types of Engineering Analysis Implemented1. Material Selection 2. Strength of Materials 3. Stability During Operation 4. Kinematic Analysis 5. Spring Selection Analysis 6. Fatigue Analysis 7. Human Interface 8. Tolerances 9. Performance Analysis
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Engineering Analysis to be Discussed1. Material Selection 2. Strength of Materials 3. Stability During Operation 4. Kinematic Analysis
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Material Selection Baseline weight found using AluminumBaseline load calculations preformed (using Al as
material) Part most likely to fail was Bowing Mechanism Locking Pin Stress = 441.3 psi x safety factor 0f 3 = 1323.8 psi
Used CES EduPack 2008 Parameters
Yield Stress > 1323.8 psi Low Ductility
Elongation of 1020 HR steel = 36% High Hardness
Material Chosen Polystyrene (20% Glass Fiber)
Polystyrene (20% Glass Fiber)Yield strength (elastic limit) 8 kpsi (55.2 MPa)Tensile strength 10 kpsi (69 MPa)Elongation 1 - 1.3 %Hardness - Rockwell R 113 – 125Fatigue strength at 107 cycles 3.9 kpsi (26.6 MPa)Overall cost of Polystyrene material for tool body $58
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Material Selection
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Material SelectionPolystyrene (20% Glass Fiber) vs. Polystyrene
Polystyrene Elongation = 10-20% Rockwell Hardness R = 75-95
Polystyrene (20% Glass Fiber) Elongation = 1-1.3% Rockwell Hardness R = 113-125
93.5 % decrease in elongation (lower ductility)33.6% increase in hardness
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Strength of Materials Parts more prone to Failure
1. Rotation shaft 2. Bowing mechanism lock pin 3. Bowing mechanism top tilt pin 4. Bowing mechanism bottom tilt pin 5. Tilt plate teeth 6. Adjustable tilting bar
Overall results Bowing mechanism lock pin
Shear Stress experienced by part =191.8 psi Safety Factor = 41.8
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Strength of Materials
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Wbase = 54.6 lbs (needed not to tip) Wactual, base = 8.7 lbs. Wadded to base = Wbase - Wactual, base = 45.9 lbs
Stability During Operation
Distance the sled needs to travel to rotate the bulb 90 °S=Rθ
S=arc length R=radius of race θ=90°
S=2.3 in.
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Kinematic Analysis
Financial Analysis Material Cost
$256 (based on store prices) 15-20% reduction in cost from mass
production would be assumed
Labor/Production/Shipping Costs $ 60(approximate)
Total Cost $316 (based on store prices)
Sales Price $998
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Financial Analysis Georgia Institute Of
Technology Labor Cost $35/hour
Product Time Savings 30%
Company Savings $11.67/hr $0.391/light bulb
≈ 2 minutes to change a light bulb
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Financial Analysis Company savings
$11.67/hr. $0.391/light bulb
≈ 2 minutes to change a light bulb
Product Payoff Rate (PPR) *PPR = 85.5 hrs. (about 2 work
weeks) *PPR = 2,553 Light bulbs
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*( Estimates do not include savings from possible reductions in insurance cost as well as worker compensation claims.)
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Prototype ModificationTilt PlatesHousing SpringMaterial Selection
Added Weight to BasePull cables replaced
with fishing line hand pulled
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Tilt plate side panels
Prototype Modification
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Housing SpringsDue to size and strength
requirements the spring need to be fabricated
Replaced with badge retracting clips
Prototype Modification
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MaterialsHousings and rotation sleds
High density PolyethyleneRotation bar and Tilt
adjusting barHR Steel
Tilt PlatesAluminum
Tilting legs, and Rotation support Structure
PVC pipe
Prototype Modification
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Replace pull cables with fishing lineDue to cost of cables
($42/cable) fishing line was substituted and will be hand pulled to create the needed motion.
Prototype Modification
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Videohttp://helix.gatech.edu/Classes/
ME4182/2009S1/projects/Team_INASAD/gallery.html
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Future Improvements1. Storage Base
Provide base weight for stability Would hold replacement and old bulbs
2. Attachable Light Would illuminate areas of low lights as well
as areas with high ceilings
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Future Improvements3. Alignment Camera
Would provide images of the working area on a screen which would be at eye level.
4. Height increase Increasing the reachable height would
make the product more usable at all ceiling heights.
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INASADFluorescent Light Changing System