Large DOF Vac

8/8/2019 Large DOF Vac

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Large Degree of FreedomHandheld Vacuum

T h e P e n n s y l v a n i a S t a t e

U n i v e r s i t y

T e a m 3

D E T A I L P R O P O S A L

M E 3 4 0

1 1 / 3 / 2 0 1 0

Aleksey Ryzhakov, Nicholas

Gunther, Josh Jacoboski,

Michael Ganci

This proposed design allows the user to clip the body of the

vacuum cleaner to the arm, freeing the wrist to perform any

type of motion with the movable suction cup. This allows

for a natural, “table cloth wiping” motion while vacuuming.



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0. EXECUTIVE SUMMARY

Our team was tasked with developing a hand-held vacuum cleaner to be marketed towards the generalpublic within a three month time window. Some initial design problems/questions the team askedthemselves were in regard to overall performance, durability, ergonomics and power output. Thecustomer needs gave passage into the concept development, which gave way to the system-level design.

This proposal will begin by describing how the customer needs were gathered and organized. The nextsection explains the concept development phase the team took, including the ranking system for ourideas. The system-level design will show solid models of our design and the scoping calculations used toshow parameters of the performance. Appendices will be included to hold relevant charts and tables thatare referenced in the body.



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1.0 INTRODUCTION 3

2.0 CUSTOMER NEEDS AND SPECIFICATIONS 3

3.0 CONCEPT DEVELOPMENT 4

3.1 External/Internal Search 4

3.2 Concept Generation 5

3.3 Concept Selection 5

4.0 SYSTEM LEVEL DESIGN 7

5.0 DETAILED DESIGN 9

5.1 Components 9

5.2 Material Selection 10

5.3 Fabrication Process 10

5.4 Bill of Materials 11

5.5 Economic Analysis 12

5.6 Calculations 13

5.7 Product Testing 14

6.0 CONCLUSION 16 (for 14 pages total)

APPENDIX-A-1 – Team Roles 17

APPENDIX-A-2 – Gantt Chart 18

APPENDIX-B-1 – Metrics and QFD 19

APPENDIX-C-1 – Problem Decomposition 20

APPENDIX-C-2 – Concept Sketches 21

APPENDIX-C-3 – Selection Matrices 22

APPENDIX-D-1 – Matlab Program 23

APPENDIX-D-2 – Detail Drawings 25

APPENDIX-D-2 – Electrical Diagram 36

APPENDIX-E-References 37

TABLE OF CONTENTS



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1. INTRODUCTION

The ACME Tool Company is looking to add a cordless vacuum to add to their arsenal of 18V hand-heldtools. ACME is opening up their doors to any company that creates a strong concept and prototype thatthey feel is appealing enough to put into production. For the project, each team is given a cordless drillto dissect and pick apart and use any part that they please. The requirement is that the motor and therechargeable 18V battery pack be used in the vacuum to make it fit into their line of cordless tools.

Using knowledge of mechanical engineering and product design, our team has gone through thedevelopment process to ensure that all requirements and customer needs are met. The project began withplanning. Team roles and project timeline have been laid out in APPENDIX-A-1 – Team Roles and

APPENDIX-A-2 – Gantt Chart , respectively. The first action item was gathering information regardingwhat consumers look for in a hand-held vacuum cleaner. Every identified need and concept has been putinto consideration to give the team a better perspective of the job at hand. The customer needs have beenorganized to group similar needs together. They were then placed into a hierarchy to aim the team’s

attention to the needs that are the most important and which need to be addressed in our design. Theneeds were then converted into target specifications that will become the building blocks for the conceptdevelopment phase. Afterwards, concepts were generated and grouped. Using selection matrices,

specific concepts were picked.

Using the generated concepts, a graphical model of the prototype was created. Throughout the project,iterative development has been used heavily to select and refine various systems.

2. CUSTOMER NEEDS AND SPECIFICATIONS

This list of customer needs was compiled by researching consumer responses to other cordless vacuumson the market and analyzing what more the customers wanted from their vacuum. Also the teamsurveyed friends and family members to see what they look for when purchasing and operating a hand-

held vacuum. A list of customer needs has been compiled by the team to direct the path of the conceptdevelopment (Table 1.0).

Many of these needs were addressed in the concept development phase of the process. These needs werereviewed by the team and placed into hierarchy tables (Table 2.0). These hierarchy tables wereorganized to the team’s interpretation of how strongly the consumers’ needs were expressed.

Table 1.0: Customer Needs

1. Contains Adaptable Suction Pad for rough

surfaces

2. Has an LED light for visibility

3. Is Lightweight

4. Allows Large DOF for movement

5. Allows for reduction in wrist bending

6. Is Usable for Dusting

7. Provides less strain on elbow joint

8. Left & Right Handed

9. Used with only one hand10. Has an extension for hard to reach places

11. Can be used lifted in various ways

(ordinary vac & large DOF vac)

12. Interchangeable Suction Pads

13. Drying pad for spills

14. Motor does not get in the way

15. Has a Blockage indicator

16. Safeguards against burn out

17. Does not produce a lot of noise

18. Can pick up things ranging from dust to

bolts19. No Disposable Filters

20. Easily Cleanable



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cleaning liquid spray into the vacuum design, mainly because of the primary design goal of maximizingsuction. Patent 5020187 detailed a filter assembly for a hand held vacuum cleaner that positioned thecollection chamber in the rear of the vacuum. While this patent documentation was helpful, weeventually decided on having the filter chamber closest to the front of the vacuum where it would bedirectly attached to the suction hose.

3.2 Concept Generation

To better understand customer needs, user functional decomposition and black box decomposition toolswere used. Both may be found in APPENDIX-C-1 – problem decomposition . Throughout the initialphase of generating concepts, the team brainstormed concepts of all aspects. These stage one ideas wereall developed on note cards by each member and organized in such a way that relative concepts weregrouped together. When a concept was pitched to the group, each member listened carefully to thedesign and reserved subjective judgment which enabled all ideas to be heard and analyzed on a leveldesign field. In lieu of concept combination charts, concepts were combined by stacking cards on top of each other to represent a wish-list final design. The rough concept sketches that were originally drawnon the note cards have been recreated by hand (see APPENDIX-C-2 – concept sketches).

3.3 Concept Selection

For concept selection, selection matrices were used to pick concepts. The matrices may be found in APPENDIX-C-3 – selection matrices. Their explanations are below. The rankings for the selectionmatrices were generated by asking customers to discuss relative importance of each weight.

The final weights were:

From this pool, 4 applicable weights were picked for each concept.

Shell Design

Final Pick: Plastic mold clamshell (for final prototype), reinforced high strength cardboard (for beta).

In analyzing the durable plastic clamshell model, the team determined that it would be fairly easy tomanufacture. A solid model could be prototyped into a working model and the overall design wouldfare well. Being a two-piece shell, the mold would fit together well since its attachments would beminimal and would be easily integrated together. Visually, the plastic shell design would be

aesthetically pleasing to the customer since all components could be fit to the mold and reduce theamount of material used. It would be sleek and the texture of the plastic mold would provide comfort tothe user.

While the sheet metal shell design would be aesthetically pleasing it would be more difficult tomanufacture. Attaining complex curvature would be harder to form with sheet metal than with a plasticmoldable material or cardboard. For this, the ease of manufacture was rated at a below average level.The ease of integration with sheet metal would be difficult as well, being that the shell would have to be

Performance –5 Durability – 3 Performance (ergonomics - comfort) – 5 Functional Performance (suction) – 6

Ease of manufacture (cost) - 4 Ease of integration into assembly (cost) - 3 Ease of use (functional ergonomics) - 6 Appeal – 3



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molded properly first in order for the design to fit together (and not be of a box-like structure). Thedurability of sheet metal, however, is considerable.

The team explored the cardboard model design the most in the alpha mock-up design phase. The useof cardboard increased formability and gave way for a quick-to-build and test process to occur. In termsof manufacturing, the cardboard method was the easiest in regard to building the shell allowed for theteam to make insertions and establish relative spacing with ease. Integrating the cardboard model withthe other parts is above average in the ranking system, though its integration would require adhesives asprimary attachment materials. Visually, the cardboard model would look somewhat unprofessional andperform below average in that category. The cardboard would have to be coated with spray paint inorder for it to look presentable.

Shell Ergonomics

Final Pick: arm clipping with free-to-move wrist concept, with an optional rigid mode.

The designs that the team analyzed ranged from standard handle models to slightly more advanced armclipping designs. The first concept incorporated a standard grip handle design for the customer to

hold on to while performing the cleaning. This model was pitched more for the purpose of a directcomparison to what most hand-held vacuum cleaners have in the current market. This would be theeasiest to manufacture and integrate into the rest of the vacuum though it is much less appealing to thearm clip models the team explored. When focusing on durability, it was determined that the standardhandle design would perform better that the other models since less parts are involved and there existsmore rigid fixtures.

The second concept had the revolutionary arm clipping design-one with a rigid suction cup, the otherwith a flexible hose. This design would take some more effort to manufacture since there would beadditional fittings for the attachments which is why it rates above average in that category. Again, thiswould not to be that difficult to integrate since it has a fixed suction cup at the end and the arm

clippings. When compared to the standard handle design, the arm clipping would provide much morerange of motion though it has the potential to be less secure since it is relying on the strength of theclippings. This design would be much more appealing than the standard handle since it increasesmobility, though the fixed suction cup limits the range of area covered. Increasing the degrees of freedom by having a rotatable cup would be much more appealing to the customer; these are explored inthe next two designs.

The final design has combined rigid and a mobile suction cup modes, with a retractable hose that isattached to the suction cup for maximum mobility. Of all the designs, this would be the mostergonomically appealing to the customer since it provides them with exceptional range of motion andmultiple forms of variations of use. The rigid attachment turns the vacuum into the fixed suction cup

design while extending the retractable hose enables the multi degree of freedom mode.

Hose and Airway

Final Pick: Flexible hose that collapses for rigid mode



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The three concepts for the type of hose are directly related to how much range of motion customer willhave. The first concept the team analyzed was the rigid pipe idea. All three designs would be relativelyeasy to manufacture, given that the hose and/or piping will be bought from McMaster-Carr at somepoint in the near future. The pipe would be the most durable since it is formed out of a solid plasticmaterial. The functionality is decreased immensely with the use of a rigid pipe since the range of motion directly depends on the location of the pipe.

The regular hose idea increases the range of motion and allows for higher mobility. With this design, aside-shell hose holster (or some type of hose attachment) would be required since the hose would not beretractable. While this would be more satisfying to the customer (compared to rigid pipe), it wouldincrease the size of the vacuum and its external parts with the addition of a regular hose. The durabilitywould be above average though not as exceptional as a solid material build. This is one of the maintrade-offs that were considered in this design selection process.

The best concept for the hose and airway design is a retractable hose. This design takes thefunctionality of a multi degree of freedom device and makes it more compact. By having a retractablehose one would be able to extend the end as far as you needed and could still utilize the vacuum cleanerin compact manner. The durability would rank slightly less than the regular hose since there would be

constant retraction and extension in this design. This may cause tearing of the hose in the long run, butthe interchangeable design would allow for the user to replace the hose.

Fan Design

Final pick will be selected after performance ratings.

Preliminary Pick: Centrifugal Pump with Backward angled, curved blades.

The fan designs that are specified in the selection criteria will be tested upon further prototyping andmanufacturing. Scoping and preliminary design of the fan is described in the next section. Allperformance calculations and testing will be described in full extent in the detail and final reports. The

preliminary pick was the centrifugal backward angled pump due to the calculations discussed in the nextsection.

4. SYSTEM LEVEL DESIGN

The proposed alpha design is presented in Figure 4.0.

Large DOF Feature:

The defining characteristic of the design is shown in Figure 5.0: the vacuum cleaner can be clipped ontothe arm, allowing the wrist itself to hold a suction cup that attaches, through a retractable hose, to thecollector. This feature allows for an unprecedented number of degrees of freedom for wrist motion.The user is able to clean surfaces using the same hand motions as cleaning using a tablecloth — perfectlynatural motion, which removes wrist strain problems that may be caused by conventional rigid handledesign.



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If, however, a rigid handle design ispreferred by some users, a rigidconnector piece can be inserted betweenthe collector and the suction cup, fixingthe suction cup in place. (Figure 6.0).

LED Dust Scanner feature:

Upon searching for better ways to makedust more visible, we remembered thefollowing phenomena: when lightstrikes dust particles on a horizontalangle, the light tends to be reflectedmostly backward —right into the user’s

eye. This drastically highlights dustparticles (this effect can be seen if onetakes a flashlight and puts it flat on the

table. Less of the table is lit up, but the dust particles become much more visible than if the flashlightwas pointed straight down on the table). This feature is simple-- it requires nothing more than twoLEDs that are horizontal. Note: the purpose of the LEDs is not so much to “light up” the table as it is to

make the light reflect off of the dust particles directly into the user’s eyes.

Refer to APPENDIX-D-2 detail drawings for more detail.

Figure 6.0: Rigid connection modeFigure 5.0: Flexible hose suction pad mode

Figure 4.0: Proposed Design



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5. DETAILED DESIGN

5.1 Components

The detailed design contains many different components for the final assembly. To see detaileddrawings for each part, see to APPENDIX-D-2 detail drawings. This section will discuss some of themore important design choices

Overall Shape and Appearance (Shell and Collector)

Early in the design process it was realized that the final design requires a smooth shape for outwardappearance in order to create a presentable design. Three different shell models have been iterativelycreated in 3D. This iterative technique allowed customer and group member input on the outwardappearance, and the final design (shown throughout this document) is a summation of various inputs onvacuum appearance. It is critical to note, however, that while the black/red color scheme (primary and

secondary colors respectively) is the default color scheme (designed to fit the drill color scheme), it issuggested that the final production include white/blue and dark red/dark red color schemes.

Straps

The three straps (two on main body and one on suction cup) have been designed to fit variable arm sizes.They are to be made out of Velcro® fabric for easy and quick adjustment and secure fit.

Handle & Rigid Piece Attachment

The handle is to be located on the side of the vacuum. It has been designed such that the handle does

not interfere with Large DOF mode use (Figure 5.0). However, if Large DOF mode is not preferable,the rigid mode attachment can be mated to the collector in place of the hose. This attachment turns thevacuum on its side, and the handle side now becomes the ―top plane‖ of the vacuum (Figure 6.0).

Filter

The filter has been designed in a cone shape. This shape allows the incoming particles to strike thesurface of the filter at a glancing angle (instead of at a normal angle), deflecting them into the collectorand preventing them from accumulating on the filter itself.

Hose, Airway, and Suction Cup

The hose has been designed to be smaller in radius than the fan inlet itself. This converts the large headproduced by the fan into fast fluid velocities that drive the dirt particle flow. The suction cup designitself has been inspired by a computer ―mouse‖, allowing for comfortable feel while per mitting freemotion.

The fan design is discussed in the calculations section.



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Electrical Routing and LED

Included in the design are two LED lights mounted on the suction cup ( for dust incidence highlighting

feature – refer to section design for description of this new feature). To determine the best design weremembered the cleaners on the market today; these vacuums include ―plug junctions‖ that allowextensions to have electrical features. The electrical routing diagram is in APPENDIX-D-3 Electrical

Diagram. The design includes interchangeable junctions which require nothing more than simplecopper wires with end plugs to connect different extensions.

5.2 Material Selection

The materials for the vacuum have been selected to reduce the cost of production and assembly. Theshell and accessories will be made of injection molded ABS (Acrylonitrile butadiene styrene). ABS is alow cost thermoplastic with good mechanical properties. Use of this material will produce accurateparts that are very inexpensive for a 100,000 unit/year run. The accuracy of injection molded ABSallows the internal assemblies to be positioned with aligning features. These assemblies are then lockedinto place when the upper casing is attached with screws.

The fan is also injection molded, but Glass Filled Nylon was selected for its superior mechanicalproperties over ABS. The Nylon construction allows the fan to withstand much larger stresses. Thisreduces the probability of injury to the customer and increases reliability by preventing a critical failure.Glass Filled Nylon is more expensive than ABS, but the cost increase is well justified by reliabilityimprovement that it offers.

5.3 Fabrication Process

The vacuum has been designed for easy assembly. This has been accomplished by carefully consideringthe placement of all essential components so that the vacuum may be assembled from the bottom up.The lower casing (all casting would be purchased from outside vendors) fixes the motor assembly,

battery, wires, and ducting. Then the upper casing is lowered onto the entire assembly and fastened withfive screws. This assembly strategy reduces the number of operations and repositioning necessary tobuild the body of the product. This process could be automated, but at this time, the team believes thathand assembly would be more cost effective due to the high initial cost of an automated assembly line.The vacuum is completed by attaching the accessories.

The accessories are attached to thebody in the same manner as thecustomer would when they use andmaintain the product, therefore thisprocess must be performed by hand.

The filter is snapped into the dustcollector frame before the filterhousing is slid into position. Thefilter housing attaches to the bodywith integrated snap connections.The suction cup assembly is attachedto the filter housing by connecting

Labor Cost per Unit at $15/hr. Wage

Operation

Time

(sec) Quantity Total Time Required

Snap 5.9 12 70.8

Screw 10.3 5 51.5

Wiring 20 1 20Repositioning 110 1 110

Time to Assemble 1 Unit 252.3

Labor Cost per Unit $1.05



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the hose, or attaching the rigid connection piece. The arm straps are also easily attached to the case withsnaps. The completed product is then sent to the test station to verify proper operation.

As shown in Table 3.0, the estimated time for the assembly of a single unit is approximately 252seconds (the time has been approximated by assembling the vacuum using a solid works model andadding a 50% safety time to account for the fact that real world assembly is not entirely lean-compliant).This time has been reduced by utilizing a pancake construction for the vacuum body and reducing thenumber of mechanical fasteners to a minimum while still preserving the structural integrity of the unit.Attaching the accessories does require some repositioning, but this has been reduced by designing aproduct that is easily maintained.

5.4 Bill of Materials

The bill of materials forthe vacuum are listed inTable 4.0. The cost of the injection molded

parts was approximatedusing three sources.Ulrich’s (237) provides atable to estimate the costto produce severalexample parts of varioussize and complexity.The calculator that wasused to estimate themolding and tooling costwas created by Dr.

David O. Kazmer, aProfessor of PlasticsEngineering atUniversity of Massachusetts. The costestimates that weregenerated by thecalculator were thencompared with referenceparts of similar geometryand complexity that have

been produced in thepast (8). The list of these parts was found on the website custompartnet.com. The estimated price toproduce our parts agreed with the examples that they provided.

BOM per unit at 100k units producedItem

#Item Name Qty

Molded?

Y/N

Volume

(in^3)Cost ($)

1 18V DC Motor 1 N - $102 18V Battery 1 N -

3 Molded Shell - Top 1 Y-1 cavity 27 1.85

4 Molded Shell-Bottom 1 Y-1 cavity 50 2.07

5 Fan 1 Y-4 cavity 1.33 1.06

6 Dust Collector 1 Y-2 cavity 6.4 1.02

7 Hose (1.2 in dia) 1 N - 0.55

8 Suction Cup 1 Y-2 cavity 4.5 1.36

9 Filter Insert 1 Y-8 cavity 1.7 0.43

10 1/8 in screws 5 N - 0.07

11 Rigid Attachment 1 Y-4 cavity 3 0.6312 Flat Extension 1 Y-4 cavity 2 0.35

13 Strap 2 N - 1.04

14 Switch 1 N 1 0.27

15 LED 2 N 2 0.02

16 Wiring Assembly 1 N 1 0.28

Cost of

Materials$21.00

Labor Cost

per Unit$1.05

Total Cost $22.05Table 4.0: Bill of Materials



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5.5 Economic Analysis

After calculating the net present value at estimated salaries of 38 total employees working on theproduct, the current NPV for a four-year timespan correlates to $1,569,945 (Table 5.0). With thismetric, the assumption is that all 400,000 units (100,000 per year over 4 years) will be sold. To accountfor potential market trends, the team analyzed what would happen if only 85% of the units were sold at$45 per vacuum. The new NPV in this case came out to equal $115,421. We also determined whatwould happen if the price had to be reduced in order to compete with other products. The team reducedthe price to $40 and the NPV with that consideration came out to be $492,520. The projected markettrend is never an exact estimation which is why the team analyzed different scenarios where the salesprice would need to be reduced or the number of units sold would decrease. Both of these cases yieldeda positive net present value.

Period 1 2 3 4 5 6 7 8

Quarter 1 2 3 4 1 2 3 4

Values are in $

Development Cost -300,000 -300,000 -300,000 -300,000

Ramp-up Cost -450,000 -450,000Marketing and Support Cost -146,250 -146,250 -146,250 -146,250

Production Cost -551,250 -551,250 -551,250

Prodution Volume 25,000 25,000 25,000

Unit Production Cost -22.05 -22.05 -22.05

Sales Revenue 1,125,000 1,125,000 1,125,000

Sales Volume 25,000 25,000 25,000

Unit Price 45 45 45

Period Cash Flow -300,000 -300,000 -300,000 -750,000 -596,250 427,500 427,500 427,500

PV Year 1, r = 10% -300,000 -292,683 -285,544 -696,450 -540,173 377,848 368,632 359,641

Period 9 10 11 12 13 14 15 16

Quarter 1 2 3 4 1 2 3 4Values are in $

Development Cost

Ramp-up Cost

Marketing and Support Cost -146,250 -146,250 -146,250 -146,250 -146,250 -146,250 -146,250 -146,250

Production Cost -551,250 -551,250 -551,250 -551,250 -551,250 -551,250 -551,250 -551,250

Prodution Volume 25,000 25,000 25,000 25,000 25,000 25,000 25,000 25,000

Unit Production Cost -22.05 -22.05 -22.05 -22.05 -22.05 -22.05 -22.05 -22.05

Sales Revenue 1,125,000 1,125,000 1,125,000 1,125,000 1,125,000 1,125,000 1,125,000 1,125,000

Sales Volume 25,000 25,000 25,000 25,000 25,000 25,000 25,000 25,000

Unit Price 45 45 45 45 45 45 45 45

Period Cash Flow 427,500 427,500 427,500 427,500 427,500 427,500 427,500 427,500PV Year 1, r = 10% 350,869 342,311 333,962 325,817 317,870 310,117 302,553 295,174

Projected NPV 1,569,945

0.0250

YEAR 3 YEAR 4

DISCOUNT RATE/4 =

YEAR 1 YEAR 2

Table 5.0: NPV



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The unit production cost was obtained from Table 4.0. All of the other NPV related costs wereestimated using approximated salary values (divided by 4 for each quarter). The related costs aresummarized in Table 6.0. Note: to account for overhead, all values were multiplied by 3 in the NPVtable.

Marketing accounting 2 $65,000 $130,000 MarketingBS Engineers 4 $75,000 $300,000 Development

PE 1 $100,000 $100,000 Development

HR 1 $65,000 $65,000 Marketing/Support

Manufacturing 30 $20,000 $600,000

Ramp

up/Production

$1,195,000

Overhead (~300% direct) (Each x3)

5.6 Calculations

The primary technical aspect of the vacuumcleaner is the suction power. According toDr. Cimbala’s textbook, backward inclined,

curved blade centrifugal impellers are themost efficient. Consequently, that is thedesign chosen for this project. Withbackward inclined blade design it isnecessary to determine the most optimalouter blade angle. Therefore, this section

will focus on calculating this angle usingexample 14-5 in the aforementionedtextbook.

Motor data used: V = 19.2 V, I = 700mA(Measured using Multimeter). Using thisdata, maximum motor power output wascalculated by assuming that the motoroperates at 40% efficiency. Therotor rotational speed was measured to be13000 rev/min. Using these initial

conditions, and assuming an ideal DC motorperformance curve, motor performance wasextrapolated for the entire curve range(Figure 1.0). Refer to Matlab code in APPENDIX-D-1 Matlab calculations fordetailed calculations.

The fan would operate through the entirerange of this curve (depending on airway

0 200 400 600 800 1000 1200 14000

0.01

0.02

T o r q u e ( N - m )

Rotational Speed (rad/s)

Motor Performance

0 200 400 600 800 1000 1200 14000

2

4

X: 680

Y: 3.84

P o w e r ( W )

Figure 1.0: Extrapolated Performance Curve

10 20 30 40 50 60 700.008

0.01

0.012

0.014

0.016

0.018

V o l u m e t r i c F l o w

R a t e ( m 3 / s )

Alpha 2 Angle (Deg)

Angle vs. Fan Performance

10 20 30 40 50 60 7015

20

25

30

35

40

H e a d ( M e t e r s A i r )

Figure 2.0: volumetric flow rate and head

Table 6.0: Production Costs



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blockage). However, for the blade design, the peak power range (3.84W, 6500 rpm) was picked foroptimization. Using those values, and using a 2.8 in diameter fan, Matlab was used to iterate volumetricflow rate and head for a wide range of blade angles to obtain a relationship curve (Figure 2.0) (Refer to APPENDIX-D-1 Matlab calculations for detailed calculations). Blade angle of 42.75 degrees waschosen. This angle gives a good balance between generated head, and volumetric flow rate.

The estimated output for the peak performance point on motor performance curve is:

P = 3.84 W Volumetric Flow Rate: 0.016 m^3/s

Rpm = 6500 rpm Pressure Head: 28.3 meters-air

Battery life at 0.7 A drain (Specs: 1.2 Ah battery):

1.2 Ah/0.7 A = 1.7 Hours

Current Rating: 0.7 A

According to Johan Gullich in his Centrifugal Pumpsbook, the optimal blade count for a fan is 7 (375).

Taking everything into consideration, the final fandesign is shown in figure 3.0.

5.7 Product Testing

To assure that our vacuum design is up to the standards that the consumer is looking for, several testswill be conducted to test different aspects and parameters of our vacuum design. These tests will allowus to gain the knowledge we need from the alpha design to implement the best ideas into the final betadesign. Many different instruments and tools will be used to aid in performing these tests and will assurethat we are getting accurate results. The tests that will be conducted will give us better knowledge of the

battery life, heat generation, durability, flow rate, suction, and the ergonomics of our design.

One of the first tests that will be conducted is testing the battery life. This will give a timeline of howlong the vacuum will be at optimum power and when the power begins to decrease. This will allow forthe team to give information to the user to allow them to keep their vacuum charged enough for theirliking. This test will be done by simply running the motor, with the fan attached, and using a voltmeterto measure the amperage. The time the battery sustains a rotating motor will be measured.

One of the tests that will need to be done to the alpha design is the heat generated by the motor. Thistest needs to be done to measure how much heat is transferred from the motor to the shell surroundingthe internal parts. The heat generation test is important because we need to assure that the distance from

the motor and the surfaces of the shell are adequate enough so that the shell doesn’t get damaged or theoutside surfaces get too hot. This test will be conducted using an infrared thermometer to measure thetemperatures of the inside surfaces near the motor, the outside surfaces of the shell to figure theconduction through the shell, and the surface of the motor itself. Since the material of the alpha isweaker and more flammable than the material that will be used for the beta design, if the alpha isdetermined to be safe with the produced temperatures, then the beta will have no problem.

Another test that will need to be conducted on the alpha design is a durability test. Since the materialfor the alpha is slightly weaker than that of the beta, this test will be used to assure that the shell design

Figure 3.0: Proposed Fan Design



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gives the vacuum the most durable shape. If the reinforced cardboard can withstand this test, then thebeta will be well over the requirements for our design. A durability test will be done to test the overallflexibility of the design. This will give us data on how much deformation the shell can withstand withoutbreaking. This part of the test will be done with a fish scale and a ruler to measure the force and thedisplacement. Another part of this test will be a drop test. This part of the test will demonstrate how highof a fall the vacuum can withstand and remain intact. This will simply be done with a measuring tapeand a ladder to allow us to mimic the vacuum from a defined height.

Once the vacuum has been fully assembled, the strap strength and comfort will be tested. Once thestraps have been attached, quick tests will be performed to assure that the straps adjust enough todifferent size arms and that the straps hold to the user’s arm while holding the weight of the vacuum.

This part of the test will be done with the straps themselves, different strap sizes and material will beused to allow us to determine the ideal strap for our design. Also, with the vacuum fully assembled, theoverall weight will be tested. The shell obviously needs to be able to hold all the parts in place as it’s in

use. Once it’s concluded that the alpha design can hold the weight of all the parts and keep it in place, it

will show us that the beta will be more than durable.

One of the main variables that determines the critical success or failure of a vacuum cleaner is the flow

rate and overall suction performance. Vacuums that produce little or no suction cannot be effectiveso we must test the flow rate against the theoretical value. The team will evaluate this variable bytesting mass flow rate (kg/s). Flow rate can be extrapolated by determining a relationship with inletvelocity. The team will use a pitot tube to measure the high end velocity. The difficult task will beattempting to measure velocity at various points within the hose, therefore we will interpolate the data toestimate the velocity at intermediate points. The goal of the vacuum cleaner is to pick up one cup of ricein a short time.

In order for fan performance to be maximized the fan must rotate symmetrically and not come incontact with the shell or any other surface that would cause frictional resistance. This problem can beavoided with the correct spacing and tolerance between the fan blade and any part in close contact with

the blade. This test will consist of the mounting of the fan onto the shaft and observing its rotationand/or potential friction.

The final vacuum model must be ergonomically suitable to the customer for them to want to use it on aregular basis, and will therefore be tested for ergonomic comfort. Comfort and functionality both comein to play when considering how the vacuum will fare in the customer’s eyes and it is important to get

the their direct opinion on the performance of the final product. The primary means for testing forergonomics will be held in controlled focus groups where individuals physically test the model.Variables that will be tested during this stage are as follows: mobility, comfort, weight balance and easeof use. This actual procedure will begin with the distribution of the product to a lead user in a controlledarea. The goal is to provide the customer with a comfortable and durable end product and to get detailed

information the team will observe how the individual uses the vacuum. Questions that are asked to theuser will be rated on a ―strongly disagree‖ – ―disagree‖ – ―average‖ – ―agree‖ – ―strongly agree‖ scale,

in a similar method to how concepts were selected. The following are examples of these feedback statements: “The product satisfies my individual needs in performing tasks. The weight of the overall

vacuum assembly is balanced. The hose is a much needed feature that gives me more mobility”. Whenthese factors are tested, the data will be interpreted to see where strengths can be identified and wherepotential areas of improvement lie.



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6. CONCLUSION

The team is making consistent progress with the design and production of the hand-held vacuum cleanerand has maintained the schedule of the Gantt chart up to now. Thus far, we have a working solid modelof the overall design of the vacuum cleaner with each part assembled in its projected position. Themodel allows us to analyze the functionality of the vacuum and address conflicting spacing issues. After

analyzing several fan/blade designs, the team has begun to equate flow rate and suction to powerdistribution. We are aggressively testing the performance of the motor and its relationship to theprojected power output that will drive the fan and provide the vacuum with air flow.

The NPV value of the project is a large positive value showing that economically speaking, this projectholds much potential. Additionally, uncertainty analysis was conducted by lowering sales quantity andprices. Even with these adjustments, the NPV remained positive. However, it is our belief that theunique features of this design will push the demand for this product beyond the 100,000/yr volume,boosting the NPV even more. We see this novel design as a profitable endeavor that will benefit both themanufacturer and the end user alike.



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APPENDIX-A-1 Team Roles

Project Management

Project Timeline Manager: Nicholas Gunther

Design Manager: Aleksey Ryzhakov

Co-managers: Michael Ganci, Josh Jacoboski

Financial Officers

Production Cost Analysis Michael Ganci

Alpha and Beta Prototype Cost Analysis/Record Josh Jacoboski / Aleksey Ryzhakov

Record Keeper

Nicholas Gunther

Safety Officer

Josh Jacoboski



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APPENDIX-A-2 Gantt Chart

This Gantt Chart is complete, with all the dates included. However, the visual bars are not included dueto large size. If needed, the gantt chart original file can be provided upon request.



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APPENDIX-B-1 – metrics and QFD



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APPENDIX-C-1 – problem decomposition

User Action Decomposition Process

Functional Decomposition

1. Grasp vacuum

with hand.

2. Adjust hand

size/comfortvia strap.

3. Turn on

vacuum via

on/off switch.

4. Locate area

that is to be

cleaned.

5 (a) Apply

suction cup

and position

to clean area.

5 (b) Detach

external hose to

locate finer area or

objects of greater

distance.

6. Remove filter

when full, then

clean and replace.

7. Repeat process

if necessary

8. Finish cleaning

when task is deemed

complete.

Electrical Storage

Switch Flip

Energy

Exhaust

Convert Stored Energy

to Kinetic Energy

Accelerate Dirt

Matter

Dirt MatterStore Dirt Matter

Heat

Create Current



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APPENDIX-C-2 – concept sketches



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APPENDIX-C-3 – selection matricies

Selection Criteriawt

A) Clamshell

(Moldable

Matl)

ScB) Piping

with motorSc

C) Sheet

MetalSc

D) Cardboard

(High

Quality)

Sc

Ease of Manufacture 4 3 12 4 16 2 8 5 20

Ease of Integration 3 4 12 4 12 2 6 4 12Appeal (Visual) 3 5 15 1 3 5 15 2 6

Performance (Expected) 5 5 25 4 20 4 20 3 15

Sum 64 51 49 53

Rank 1 3 4 2

CONCEPTS - SHELL MANUFACTURE


A) Standard

HandleSc

B) Arm

Clipped w/

Rigid Suction

Cup

Sc

C) Arm

Clipped with

large DOF

(Hose) Cup

Sc

D) Mixed -

Arm Clipepd

Large DOF w/

Rigid Option

Sc


Ease of Integration 3 3 9 3 9 4 12 3 9Durability 3 4 12 3 9 3 9 3 9

Ease of Use (Customer Appeal) 6 1 6 3 18 4 24 5 30

Sum 47 52 61 64

Rank 4 3 2 1

CONCEPTS - SHELL ERGONOMICS

Selection Criteria wt A) Rigid Pipe ScB) Regular

HoseSc

C) Accordion

CollapsibleSc

Ease of Manufacture 4 4 16 4 16 4 16

Ease of Integration 3 5 15 4 12 4 12

Durability 3 5 15 4 12 3 9

Function Performance 6 2 12 4 24 5 30

Sum 58 64 67

Rank 3 2 1

CONCEPTS - HOSE & AIRWAY


A) Axial

Angled FlatSc

B) Axial Angled

CurvedSc

C) Centrifugal

Angled CappedSc

D) Centrifugal

Angled OpenSc


Ease of Integration 3 3 9 3 9 2 6 2 6

Durability 3 3 9 2 6 5 15 4 12

Performance (Actual Tested) 5 3 15 TBD TBD TBD TBD TBD TBD

Sum 45 27 29 30

Rank

CONCEPTS - FAN **Incomplete - Need Performance Test



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APPENDIX-D-1 – matlab program

%% Aleksey Ryzhakov, Fan Performance Calculations: clcclear

% The following Motor Specs were measured and obtained from the manual V = 19.2; %V I = 0.5; %mA

% Knowing that power = V*I, the maximum ideal power of our motor is Pmax = V*I;

%Using tachometer, the maximum RPM of our motor was calculated to be wmax = (13000*2*pi)/60; %rad/s

% At maximum efficiency, w = 1/2 wmax and torque = 1/2 t_stall % Therefore,

Meff = 0.4; % Maximum Motor Efficiency --ASSUMED VALUE

Pp = Pmax * Meff; % peak power

% Using IDEAL DC MOTOR curve equations from % http://lancet.mit.edu/motors/motors3.html (9) % We get the following equations:

wp = wmax/2; % w at peak power Tp = Pp/wp; % Torque at peak power Ts = 2*Tp; % Stall Torque

w = 0:10:wmax; %define w

T = Ts - w*Ts/wmax; % P = -(Ts/wmax)*w.^2+Ts*w;

figure(1)[AX2, H12, H22]=plotyy(w,T,w,P);set(get(AX2(1),'Ylabel'),'String','Torque (N-m)')set(get(AX2(2),'Ylabel'),'String','Power (W)')xlabel('Rotational Speed (rad/s)')

Title('Motor Performance')

% For fan design - ITERATE

z = 0;

angle_delta = 50; % Degree change of normal vectors of blade curvature from



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%inlet to outlet (Blade curvature dependent variable).

% THE FOLLOWING CALCULATIONS WERE PERFORMED USING EXAMPLE 14-5 FROMFLUID % DYNAMICS BOOK WRITTEN BY DR. John Cimbala

for ALPH2 = 10:1:70z = z+1;

alpha2 = (ALPH2)*pi/180; %Outer Air Velocity Angle alpha1 = (ALPH2-angle_delta)*pi/180; % Inner Blade Air Velocity Angle

r1 = 0.75*2.54/100; %Inner Radius r2 = 1.5*2.54/100; %Outer Radius b1 = 0.8*2.54/100; %Inner Blade Thickness b2 = 0.5*2.54/100; % Outer Blade Thickness g = 9.81; % Gravity

rho = 1.2; % air density at stp

for Vdot = 0.001:.0001:.03V1n = Vdot/(2*pi*b1*r1);V1t = V1n*tan(alpha1);V2n = Vdot/(2*pi*b2*r2);V2t = V2n*tan(alpha2);H = wmax/g*(r2*V2t-r1*V1t);

bhp = rho*g*Vdot*H;if bhp>Ppbreak end

end

bhpselect(z) = bhp;hselect(z) = H;vselect(z) = Vdot;alphaselect(z) = ALPH2;angledelta(z) = angle_delta;end

disp(vselect(angle_delta))

figure(2)

[AX, H1, H2]=plotyy(alphaselect,vselect,alphaselect,hselect);set(get(AX(1),'Ylabel'),'String','Volumetric Flow Rate (m^3/s)')set(get(AX(2),'Ylabel'),'String','Head (Meters Air)')xlabel('Alpha 2 Angle (Deg)')Title('Angle vs. Fan Performance')



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APPENDIX-D-2 – DETAIL DRAWINGS

ILED

DRAWINGS



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GLASS NYLON

GLASS NYLON



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APPENDIX-D-3 ELECTRICAL DIAGRAM

Housing

Collector Hose/Suction Cup LED

Rigid Piece/Suction Cup

Junction

Vin

Battery-

+

V motor

Switch

Vl

Rl

Junction



APPENDIX-E – REFERENCES

(1) U.S. Patent No. D480846S (issued Oct. 14, 2003).

(2) U.S. Patent No. 5970572 (issued Dec 10, 1997).

(3) U.S. Patent No. 5020187 (issued March 19, 1990).

(4) Cimbala, John. Fluid Mechanics. Boston: McGraw-Hill Higher Education, 2010.

(5) Gülich, Johann. Centrifugal Pumps. Berlin: Springer, 2010.

(6) Ulrich K, Eppinger S. Product Design and Development. New York: McGraw-Hill; 2008.

(7) University of Massachusetts Lowell [Internet]. Lowell (MA): Dr David O. Kazmer: c2010 [cited2010 Oct 18]. Available from: http://kazmer.uml.edu/Software/JavaCost/index.htm

(8) CustomPart.net Part Gallery [Internet]. Olney (MD): CustomPartNet: c2009 [cited 2010 Oct 18].Available from: http://www.custompartnet.com/

(9) ―D.C. Motor Torque/Speed Curve Tutorial:: Understanding Motor Characteristics." Lancet

WWW Server . Web. 20 Oct. 2010. <http://lancet.mit.edu/motors/motors3.html>.

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