Gate 3 Content

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Contents

Purpose

After Completing our dissection of the Toro CCR 1000 snow thrower, we were able to study our machine on a components and subsystem level. With further examination we were able to determine the size (L,W,H), weight, materials make up and manufacturing process behind each components design.

Product Management: Coordination Review

With only a month left in the semester there has been much more additional stress and conflicts in scheduling due to exams, papers, and final exam preparation. With this being said, we as a group are definitely struggling to complete the gates with the level of complexity in which we are being graded upon, in addition to have already lost 2 group members. The matter in which we are dealing with these issues are breaking the gates up into sub gates to allow for less rush and panic as the gates due date’s approx. The loss of the two group members has really set us back a great deal; we have lost the only member who knew how to use wiki, and our technical writer. These were two very big components to the group’s overall success. But as in the working world you must push on and develop solutions, which is one of the reasons we have all chosen engineering, we are problem solvers.


Gate three also consisted of the three dimensional design components. Josh has added onto his already difficult workload and decided to learn how to use Autodesk Inventor, a software package, well enough to do these three component renderings for our group.


Finally, with our worldly knowledge of materials and their properties, it was very difficult to find the type of specific material that Toro has used in their product. We have attempted to contact Toro on two separate occasions for specific questions on the exact materials, and have had the door closed on us by them. Apparently they keep their product information, and processes very secretive.

Product Archaeology: Product Evaluation

Sand Casting

Sand Casting- is a casting process that takes a formed mold and presses a sand mixture around it, after the molten liquid metal is poured into the cavity of the mold, it is cooled and sand shell is broken off to reveal final product.

Surface Finish- the green sand that is used in the process imparts a rough texture to the surface of the cast product; the product however can be ground and polished to desirable finish.

Design Requirements- A taper, or draft must be used so no orthogonal corners can skew the mold when removing the cast part from the mold, and provides proper flow through the piece.

Obstacles in determining Sand Castings- as mentioned earlier the product will have a rough finish, but can be polished and ground to provide ideal finish. Finally the process is relatively cheap with influences the Economical factor, as well as the sand being able to be reused after proper cooling which makes it ideal for Environmental, and Societal, with the big hype on conserving resources.

Stamping

Stamping- can include a vary vast array of terms and process inside of it, such as, punching, machine press, banking, embossing, bending, flanging, and coining. This is why a general term stamping is being used in this scenario, the process can be done using a piece of sheet steel and stamp its desired shape, and can be followed by bending to desirable shapes and edges.

Surface Finish- Will have the surface finish that of the material it is stamped from, but can later be painted, heat treated, quenched and annealed, or other processes to give it a desired finish.

Design Requirements- the design requirements are much lower than that of other Manufacturing Processes, but much upfront design work will be taken into account to factor in yield, and ultimate strength of the material being used in its desired shape and loading scenario. Due to the bending of the material it will cause recrystallization of the material which can affect its final strength.

Obstacles in determining the Process- We used assumption to predict the process being used for that of stamping due to many other additional processes that could have been used, but based on future research we found that it is very common in automotive and highly reproduced products. Which we figured could very well be the snow blower made by Toro, a large company. The process has a high upfront cost of design and integrating of the machining process but can be done via full automation once properly set up.

Vacuum Forming

Vacuum forming- it is a thermoforming process which takes sheet plastic and heated to forming temperature independent of the type of plastic, and then is stretched over a surface mold. The vacuum is then applied to press the liquidous plastic against the mold to form its desired shape. Draft angles like that in investment, and sand cast must be taken into consideration.

Surface Finish- due to the thermoforming nature of the process it will have a naturally smooth finish as long as proper heating and cooling is done to the product.

Design Requirements- Normally shallow and thin walled thermoplastics are desired for vacuum forming.

Obstacles in Determining Process- after researching the difference types of plastic processesing we had ruled out blow molding, which is normally reserved to bottles. The process is very common, and relatively quick and affective.

Wire Drawing

Wire Drawing- is a process which reduces a cross section of wire through multiple dies, very commonly used to produce, electrical wire, cables, springs, spokes, and musical strings for instruments. Drawing is considered a cold work process due to the nature at which it is performed at, the room temperature process adds additional strengthening to the product when finished.

Surface Finish- the finish is smooth, due to the cold working process which stretches the material and doesn’t allow any liquidous material to form to skew the shape.

Design Requirements- The dies used to reduce the size of the metal is a very expensive part of the process; it is typically made from tungsten carbides, or diamond.

Obstacles in Determining Process- it was fairly easy to determine that our springs were done via wire drawing, since its only competitor is extrusion, but that is a process where the material is being pushed rather than pulled through the dies.


Complexity Scale

1- Highly ductile material with no surface finish, and no signs of heat treatment to the component

2- Highly ductile/formable material with surface finish, and possible heat treatment

3- Intricate mold pattern with no finish, but involved a specialized process such as investment, or sand casting

4- Multiple step process for manufacturing the component has signs of finishing, and machining.

5- Highly complex product with all four influences involved in the selection process, and involves complex mold, or processes, typical for highly in depth 3D designs.

The complexity scale was established to allow for a means of determining how intricate the process being used to manufacture the final product will entail. The dimensions of the product will establish a means of determining what type of casting process could have been used, if the product is large we know investment or lost wax casting will not be used, it would typically be sand casting. Furthermore, processes such as plastic vacuum molding, and the weaves for the cloths used were not elaborated on in class, so we did external research to try to give the best estimate possible in our findings. Finally, some of the engine components seem to be cast but can not tell without looking at the grains of the metal, the grains would appear like Styrofoam balls if it were cast, and more compressed if it were stamped and heat treated.

Model number- the only component that has a model number on it was that of the spark plug, which is listed under its detailed analysis of the component. Please refer to that section for the information.

Numbers of times the Component used- due to the motor being only a single piston, and only having one rotor, the only components that are used in multiples are the wheels (2), this is due to the straight forward design of the product.

Functions & Flows- Please refer to the functional model for the following flows, interactions and functions that are to be illustrated, the components will be described, flows illustrated.

Table 8a: Components
Component Discharge Chute
DischargeChute.jpg
Rotor Housing
RotorHousing.jpg
Chute Retainer
ChuteRetainer.jpg
Chute Detent
ChuteDetent.jpg
Detent Spring
DetentSpring.jpg
Chute Handle
ChuteHandle.jpg
Dimensions

(LxWxH) inches

13x7x5 12x19x10 8.5 diameter 8.5 diameter ring 1.5 16x7x9
Weight >1lb ~1.5lb ~1lb ~1lb >1lb 1.5lb
Materials Used Sheet Steel Plastic Steel Steel Steel Plastic
Color Black Black Black Black Black Black
Surface Finish

(Functional or aesthetic)

Paint, possibly heat treated or annealed and quenched Smooth finish, sanding (Aesthetic) Paint, possible heat treatment,(Aesthetic) Paint, possible heat treatment,(Aesthetic) Paint, possible heat treatment,(Aesthetic) Paint,(Aesthetic)
Manufacturing Process Rolled Sheet Press or Vacuum Forming Stamped Stamped Wire Drawn Press or Vacuum Forming
Was Material Selected for a specific reason? Strength, deflection resistance Cheap, complex mold structural strength, deflection resistance structural strength, deflection resistance high yield strength, and recovery strength Cheap in cost, and complex 3 Dimensional Design
Manufacturing Complexity 2 1 2 2 2 3
Societal Influences nonlead based for health safety Plastics are socially exceptable due to their reformability and recycling processes Non-lead based for health safety, and possibility to be recycled Non-lead based for health safety, and possibility to be recycled Reused recycled products Sand is reusable for cast
Economical Influences Steel alloys can be cheap and good ductility for the forming of the cylinder Cheap, societal-easily found, enviornmental-recycled, no oar extracted from the earth Additional cost for paint, but will provide rust resistance Low cost, through recrystallization the steel will become stronger Plastic is low cost and able to be melted down from previously recycled products Plastic is low cost and able to be melted down from previously recycled products
Environmental Influences Possibility to be recycled Possibility to be recycled Possibility to be recycled, High availability Possibility to be recycled, High availability Possibility to be recycled, High availability Possibility to be recycled, High availability
Global Influences Steel refineries are common in the USA, and able to get product easily. Many companies can make product Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily.


Table 8b: Components
Component Chute Deflector
ChuteDefloctor.jpg
Chute Crank Support (Not on our product) Handle Assembly
HandleAssembly.jpg
Chute Seal Retainer
ChuteSealRetainer.jpg
Chute Seal
ChuteSeal.jpg
Upper Shroud
UpperShroud.jpg
Gas Cap
GasCap.jpg
Dimensions

(LxWxH) inches

6x7x6 NA 1" Diameter Tube 8.5 Diameter 8.5 Diameter 12x19x10 2" Diameter
Weight 1lb NA ~5lb ~1lb ~1lb ~1.5lb ~.5lb
Materials Used Plastic NA Steel Steel Steel Plastic Plastic
Color Black NA Black Black Black Black Black
Surface Finish

(Functional or aesthetic)

Paint,(Aesthetic) NA Paint, possible heat treatment,(Aesthetic) Paint, possible heat treatment,(Aesthetic) Paint, possible heat treatment,(Aesthetic) Smooth finish, sanding (Functional) Paint,(Aesthetic)
Manufacturing Process Plastic investment mold NA Drawn and Welded Stamped Stamped Press or Vacuum forming Press or vacuum forming
Was Material Selected for a specific reason? Cheap in cost, and complex 3 Dimensional Design NA Cheap in cost, good resisdual strength, and torsionally strong structural strength, deflection resistance structural strength, deflection resistance Cheap, complex mold Cheap, complex mold
Manufacturing Complexity 2 NA 3 2 3 1 2
Societal Influences Sand is reusable for the cast NA Able to be found in many countries, in common stock sizes Nonlead based for health safety, and metals can possibility to be recycled Nonlead based for health safety, and metals can possibility to be recycled Easily found in many countries Easily found in many countries
Economical Influences Plastic is low cost and able to be melted down from previously recycled products NA Is made in bulk, and stocked by many companies, it is used in multiple applications which makes it relatively cheap to stock, and manufacture High production rate, with full automation possibility which will allow for inexpensive manufacturing High production rate, with full automation possibility which will allow for inexpensive manufacturing Plastic is low cost and able to be melted down from previously recycled products Plastic is low cost and able to be melted down from previously recycled products
Environmental Influences Possibility to be recycled, High availability NA Possibility to be recycled, High availability Possibility to be recycled, High availability Possibility to be recycled, High availability Possibility to be recycled, High availability Possibility to be recycled, High availability
Global Influences Plastics shouldn’t be an issue in foreign countries, other than the possible need to import the products NA Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Plastics shouldn’t be an issue in foreign countries, other than the possible need to import the products Plastics shouldn’t be an issue in foreign countries, other than the possible need to import the products


Table 8c: Components
Component Idler Spring
SpringG24.jpg
Idler Pulley
IdlerPulley.jpg
Idler Arm
IdlerArm.jpg
Cable
CableG24.jpg
Brake Spring
BrakeSpring.jpg
Glow Plug (or Spark Plug)
SparkPlug.jpg
Dimensions

(LxWxH) inches

1.5" 1.5" Diameter 7x3x.2 1/16" Diameter x 3ft 1" Diameter x 7" (At idle compression 1" part # CJ8Y


Weight >1lb >.5lb ~1lb ~.5lb ~.5lb ~.5lb
Materials Used Steel Aluminum Steel Cording, cloth exterior Steel Copper, Aluminum
Color Black Silver Silver Black Black Silver
Surface Finish

(Functional or aesthetic)

Paint, possible heat treatment (Aesthetic) None None None Paint, possible heat treatment (Aesthetic) None
Manufacturing Process Wire drawn Sand cast Sheet rolled and shaped Weave Wire drawn Unknown
Was Material Selected for a specific reason? High yield strength, and recovery strength Cheap, high level of Ductility Cheap, high torsional resistance High level of axial strength High yield strength, and recovery strength High electrical conductivity
Manufacturing Complexity 2 1 2 2 2 3
Societal Influences Nonlead based for health safety, and metals can possibility to be recycled Aluminum is widely found and doesn’t cross any religious boundaries Sheet metal is easily manufactured in many countries Can be made from nylons, carbon fiber weaves, and is socially exceptable in many countries Nonlead based for health safety, and metals can possibility to be recycled Aluminum is widely found and doesn’t cross any religious boundries
Economical Influences Many companies draw wire springs, most likely Toro does not do their own drawing, rather probably subcontract the products out, or use common springs Due to the reusability of sand, and having low cost molds made make the process very economical High production rate, with full automation possibility which will allow for inexpensive manufacturing Can be made specially for a process or can bought in bulk for this application due to the simplicity Many companies draw wire springs, most likely Toro does not do their own drawing, rather probably subcontract the products out, or use common springs Due to the reusability of sand, and having low cost molds made make the process very economical
Environmental Influences Possibility to be recycled , High availability Possibility to be recycled , High availability Possibility to be recycled , High availability Nylons are very commonly used, and never spoken bad of to the enviornment, the resons used however need to be watched for their impact Possibility to be recycled , High availability The sparkplug involves many different materials, and interactions. Injury is possible from ill treatment of the component
Global Influences Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Different types of cordage is found all over the world, however with the technology of our planet any product can be brought to you Steel refineries are common in the USA, and able to get product easily. If a car, lawnmower, snow blower, or weed waker is found in your country sparkplugs will be available


Table 8d: Components
Component Cylinder Head
CylinderHeadG24.jpg
Piston
PistonG24.png
Crankshaft
CrankShaftG24.jpg
Rotor
RotorG24.jpg
Wheels
WheelsG24.jpg
Dimensions

(LxWxH) inches

7x6x6 3x8x3 9x3x3 20x8x8 4.5"Diameter
Weight 2lb 2lb 4lb 8lb 1lb
Materials Used Aluminum Steel Alloy Steel Alloy Rubber, some Aluminum braiding reinforcement Rubber,Aluminum
Color Silver Silver Silver Black Black and White
Surface Finish

(Functional or aesthetic)

None Heat Treated,(Functional) Heat Treated,(Functional) Paint (Aethetic) Paint (Aethetic)
Manufacturing Process Casting Process (Either investment or sand) Die Casting Drawn and Welded Vulcanization Cast/Rubber-Vulcanization
Was Material Selected for a specific reason? Good heat resistance, and friction wear High heat resistance to yield and torsional resistance High heat resistance to yield and torsional resistance Cheap low wear resistance Low Cost
Manufacturing Complexity 5 4 4 2 2
Societal Influences Aluminum is widely found and doesn’t cross any religious boundaries Provides a very strong material and very resistant to impact loading Is widely found in many countries and doesn’t discriminate any religious views Is widely found in many countries and doesn’t discriminate any religious views Is widely found in many countries and doesn’t discriminate any religious views
Economical Influences Due to the reusability of sand, and having low cost molds made make the process very economical Very expensive process due to the upfront engineering involved in processing the dies Most likely was bought from a company that draws steel pipe, and then was bend to desired shape Rubber and Aluminum are relatively cheap and widely found Rubber and Aluminum are relatively cheap and widely found
Environmental Influences Possibility to be recycled , High availability Possibility to be recycled , High availability Possibility to be recycled , High availability The processing of rubber can be very hazardous to the enviornment if certain percaustions are not met The processing of rubber can be very hazardous to the enviornment if certain percaustions are not met
Global Influences Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. Steel refineries are common in the USA, and able to get product easily. International countries don’t have as many emission codes as the USA, which could be very possiblely outsourced International countries don’t have as many emission codes as the USA, which could be very possiblely outsourced

3D Modeling

In this Gate we were assigned to make 3-5 solid models of different components. As a small group our knowledge of this topic was limited which forced one of our members to step up and learn a CAD package.



Piston Arm
Figure # 1
Piston Arm
we decided to choose this object due to its crucial application in the process of powering our system.


Exhaust Housing1
Figure # 2
Exhaust Housing 1
The exhaust housing was chosen due to the process in which it is manufactured, it is a two part component that is then pressed together to form the housing. The application we concluded was used was that of molding and stamping.


Exhaust Housing2
Figure # 3
Exhaust Housing 2
This is another view of the Exhaust Housing


Pulley 1
Figure # 4
Pulley 1
This three part system illustrates the pull cord pulley assembly, we chose this component to show how complex we were able to adapt and learn a 3D modeling program, Josh excelled quickly and was able to break components up even further than we expected.


Pulley 2
Figure # 5
Pulley 2



Pulley 3
Figure # 6
Pulley 3

Design Revisions

1. The center bracket for the starter pulley can be improved upon by changing the material it is made out of from its current material to aluminum. Aluminum is light and in comparison, easy to manipulate. it is also rather strong for its weight. Because of its ease of manufacturability, it is a fairly cheep material to use. The currant weight of the component is 2.5 Oz, or .1563 lb where this same part out of aluminum would weigh .0914 lb. This is about a 42% weight drop, and that will make pull starting the engine just that much easier.

2. The pulley itself could have the same revisions done to it. the pulley currently weighs 15.5 Oz, or 0.9688 lb where the aluminum version would weigh ~ .554 lbs this is about a 43% drop in weight. The combined weight of the two components is currently 1.125 lb, when changed to aluminum they weigh .645 lbs and have an overall drop in mass of 43%. This machine is not only for able bodied people but it is more likely being marketed to the elderly, or a person living in the suburbs with a small area needing to be cleared of snow. Therefore it is sensible for the machine to be light overall and for the pull start mechanism to be as easy to use as possible.

3. The current muffler seems to be made by stamping out the two separate shapes from sheet metal and then when the two components are put face to face the edges are crimped over, connecting the two components. I think that this component could be improved upon by eliminating the excess from the edges that gets crimped and instead lay one sold bead of weld down the seam. This will eliminate the ability of road salts and water from getting into the joint between the components, therefore limiting the amount of rust and corrosion that will form on the muffler, and extending the life of the machine.

Engineering Analysis

The auger on a snow blower is perhaps the most important component to the function of the snow blower. For this reason the material used for its construction must be carefully considered for a few reasons. First and foremost, the material that the auger is constructed of must be able to perform the intended task, which in the case of a snow blower is to jettison snow out of the chute. While the function of the material used to construct the auger is of utmost importance, it is also imperative that the material is able to withstand the wear and tear that the auger will undergo, while performing the intended task. There are many things that must be considered to ensure that the material used for a specific task will be the best choice, and in the case of the auger on a snow blower, but two very important things to consider are the amount of friction the material encounters with both the ground and the snow, the amount of flex and torsion the material can withstand. In the particular case of the Toro snow blower, the material that was determined to suit the job best was a hard rubber. The engineers who determined the material used for the auger needed to use many equations to figure out which material would work best. The following equations can be used to help determine the right material for the task:

Ffriction=μFnormal

μ is the friction constant

J=βab²

a is the length of the long side of the beam

b is the length of the short side of the beam

β is found using the table such as:

Table 9
a/b β
1.0 0.141
1.5 0.196
2.0 0.229
2.5 0.249
3.0 0.263
4.0 0.281
5.0 0.291
6.0 0.299
10.0 0.312
0.333