Group 17 - For Kawasaki® KFX® Power Wheels: Gate 3

Purpose

With the product dissected, complete the detailed analysis of the product. In this stage we will examine the product at the component and subsystem level, gathering detailed information and will present the information in form of a technical report.

Project Management: Coordination Review

As the group finishes the third gate it is important to once again assess how the group has worked together. The group continues to follow the management plan that was set up in the 1st gate. Gate 3 was completed without any conflicts.

The group was able to meet at its scheduled times, and everything that needed to be completed was finished on time. At the end of each meeting, a list of tasks were given out to each member to complete before the next meeting.

A minor change was made in the work proposal. Parth and Dhruv took over the responsibility of 3D modleing. Isaac worked on the project management and product archaeology with Sam. These changes allowed the group to complete the gate faster and at a higher level.

One way the group can improve report quality is to upload the report to the wiki earlier. For the previous gates the report was uploaded the day it was due. If the report is uploaded a day or two before tits due, the group will have the opportunity to revise and add material if needed.

Looking forward to the next gate, Parth and Dhruv will get ready to reassemble the product, while Sam and Isaac will work on the Design revisions.

Product Archaeology: Product Evaluation

Component Summary

Part	Quantity	Component Function	Materials Used	Manufacturing Process used	Model Number	Picture
Body	1	Structural support, aesthetical appeal of real motorcycle body	Silver plastic (melamine)	Injection molding	n/a
Brush Guard	1	Acts as a bumper. Aesthetic appeal of a motorcycle front plate component	Silver plastic (melamine)	Injection molding	n/a
Black Front Wheel Attachment	2	-	black plastic (nylon)	Injection molding	n/a
Seat	1	Serves as an interface between the passenger and the body of the bike	black plastic (nylon)	Injecting molding, sand blasting for texture	n/a
Right Foot Pedal	1	serves as an interface between the passenger’s physical signal and the internal motor to accelerate the bike	black and gray plastic (polypropylene)	Injecting molding	n/a
Steering Column Cap	1	Aesthetic appeal mimicking the front plate of a motorcycle	Black plastic (melamine)	Injecting molding	n/a
Front Plate	1	structural support. Aesthetical appeal of a motorcycle front plate.	Black plastic (melamine)	injection molding, sand blasting (for texture)	Q505-2349-01
Wheel Cover	4	protect the outside of the wheels from environmental damage	silver plastic (polypropylene)	injection molding	B9272-Q504-01-8
Battery Retainer	1	holds the battery in place inside the bike.	white plastic (nylon)	injection molding	n/a
Battery wires	1	connects the battery to the accelerator to send signals from the passenger.	Copper wire, insulating casing (polyvinylcholoride; PVC)	-	n/a
Motor Component	1	The motor converts electrical energy to mechanical energy to generate the overall acceleration of the bike.	plastic (polypropylene), wire, insulating casing for wires (polyvinylchloride), metal connections	injection molding (plastic), die casting (metal)	2949-Q1
Left Foot Rest	1	for the passenger to place their left foot (ergonomics)	plastic (polypropylene)	injection molding	B9272-Q506-01-1
Steering Column	1	Connects the handlebar component to the body of the bike. Structural integrity.	Metal	Die casting	n/a
Switch Component	1	The switches themselves are used to determine how fast or slow the bike will accelerate. The black box is used to encase the switches and hold them to the body of the bike, while the metal linkages serve as connections to internal electrical components.	metal and plastic (polypropylene)	die casting (metal) and injection molding (plastic)	B9272-Q514-01-1
Hand Grip	2	Provide friction on handlebars for passenger’s physical grip on the bike	Black rubber-like plastic (elastomer)	Injecting molding	J8427-Q504-0141
Circulor Motor Support	2	protective barrier for the motor, connected to the rear wheel drivers	black plastic (polypropylene)	Injecting molding	B9272-Q510-01-3 & B9272-Q510-01-4
Left Spring Cover/Right Spring Cover	1 each	The shape is to mimic the aesthetic similarity of motorcycle light covers. Physical function is to act as a side bumper.	white plastic (polypropylene)	Injecting molding	J8472-Q506-01-1
Back Axle	1	holds together motor gear box, gear box component, driver component, and both rear wheel components	metal	die casting	n/a
Front axle	2	holds together steering linkage to both front wheel components	metal	die casting	n/a
Wheel(Front and Rear)	2 Front, 2 Rear	Provide rotational motion for bike	Black plastic (ABS)	Blow molding	80272-0801-01-3
White rear wheel attachment	2	Connection support for front wheels	White plastic (nylon)	Injection molding	n/a
Rear Wheel Driver	2	Aids in the rotation of the wheels. Connected to a circular motor support and the wheel bushing	black plastic (polypropylene)	Injection molding	# 3, #4
Battery Circuit	1	Converts chemical energy to electrical energy	Epoxy, fiberglass	Drilling, etching, sodering	n/a
12V Battery Box	1	power source for the bike	The casing of the box is a black plastic (polypropylene), while the battery itself is made up of chemicals (potentially a nickel-cadmium battery)	injection molding (plastic), the chemical component could be a series of cells connected in series to achieve a voltage of 12V.	1839LC2
Screw(2.6cm)	57	Holds components together	Metal	Die casting	n/a
Screw(1.2cm)	2	Holds components together	Metal	Die casting	n/a
Metal Washer	2	Holds components together	Metal	Die casting	n/a
Metal Nut	3	Holds components together	metal, nylon plastic interior	Die casting	n/a
Body Part	1	structural support, aesthetic functionality to appear like a motorcycle	red plastic (epoxy resin)	injection molding	n/a
Hubcaps	4	Aesthetics. Mimics the functionality of hubcaps on a real motorcycle, which would be to protect the lug nuts from the environment.	silver plastic (polypropylene)	injection molding	n/a
Handle Bar component	1	Connects the hand grips and steering column, has the physical structure necessary for the action of physically steering the bike	metal	Die casting	n/a
Front Cap	1	Asthetics, covers welding of the steering column and handlebar component	Red plastic (polypropylene)	Injection molding	J8472-Q502-01-1

Product Analysis

Front plate:

Functions:
Serves as a protective boundary between the main body of the bike and the environment. The plate also has aesthetic purposes, to mimic the frontal design of a real Kawasaki. The front plate functions in all environments.

Form:
The front plate is shaped like a rectangle. The front plate is symmetrical in the y-axis. The part is primarily three dimensional. The front plate is about 12x6x1 inches. The part is shaped like this so it can perform the task it was designed to perform. It is big enough to create a boundary between the bike and the environment. Roughly the component weighs 1 pound. The plate also has aesthetic purposes, to mimic the frontal design of a real Kawasaki. The color of the front plate is black, this is to match the rest of the bike. It has a smooth surface finish, this is for aesthetic purposes.

Manufacturing Number:
Q505-2349-01
Manufacturing methods

Manufacturing methods used to make this part:

- Injection molding

• Material choice highly impacted the manufacturing method because the front plate is made entirely of a hard, glossy plastic called melamine. Injection molding is an ideal manufacturing method for the commercial production of plastic components.

• The shape of the front plate is relatively complex, in order to effectively mimic the realistic motorcycle elements. The plate is not just a solid shape; it also contains openings that are thinly connected to the rest of the component. Molding allows for more complex geometry to be created.

• Parting lines and ejector pin marks are present on the front plate, which are common indentifying characteristics of the injection molding process.

• Economically, there is an added cost to individually make each front plate component by injection molding. Molding is an efficient way to be able to mass produce a particular plastic component.

• The environment is relatively unaffected by the injection molding process, because the mold can be reused. This reduces the amount of excess waste material that could be released into the environment.

- Sand blasting (beat blasting)

• Sand blasting is appropriate for hard materials, such as the melamine plastic the front plate is made from. It is mainly used for decorative purposes. In the case of the front plate, sand blasting was used to add texture to the surface of the plate.

• The underside of the front plate represents the original condition a smooth plastic, while the middle section of the plate on the reverse side is rough. Unless a manufacturing method like sand blasting was used to give rise to such texture, the front and back of the plate would both be a smooth plastic.

• Societal factors influenced the decision to use sand blasting on a portion of the front plate. The Kawasaki KFX bike is meant for a child, but it is designed to mimic an actual metal motorcycle. The textured section of the front plate is an attempt to add aesthetic similarity to the front plate engine component of a motorcycle.

• Economically, it would cost the company more to take this additional step and sand blast the plate, instead of just leaving it as a smooth plastic.

Material Choice

Impact of the Material Choice:

- Manufacturing Decisions

• Plastic can easily be molded to fit a variety of geometries, so it is ideal for creating a medium-sized component with relatively complex geometry. It is also a lightweight material with a decent degree of strength. Plastic is economically cheap to obtain and manufacture commercially.

• The specific chemical properties of the plastic melamine make it a decent type of plastic to be used for the front plate of the bike. Melamine (melamine formaldehyde) is a thermoset plastic typically used for its strength. It creates a glossy finish, which is evident in the front plate component. A strong plastic is needed for the front plate because the plate acts as a protective boundary between the body of the bike and the environment.

• It is evident that the company does not take into account the effects of plastic on the environment. Plastic is not easily recyclable, yet it is widely used in the production of fisher price components. The front plate is mass produced as a necessary component to the Kawasaki KFX, being made completely out of non-degradable plastic.

• Globally, plastic is an easily accessible and widely used resource. It is not difficult to get enough plastic to be able to commercially distribute the components of the Kawasaki KFX.

• Economically, plastic is cheap. Specific types of plastic are more expensive to create than others because of their chemical makeup and strength to weight ratio, but melamine plastic is relatively inexpensive. This also allows for the overall consumer price of the product to be lower.

• Socially, fisher prices needs to make sure they are creating their product component within manufacturing safety regulations, like the amount of lead that is present in the plastic.

Wheels

Functions: Provide rotational motion. Gives the bike added height and ground support. It does this by being turned by the axle. The wheels will function on a flat dry surface.

Form:
The general shape of the wheels are circular. The wheels are axis-symmetric. The wheels are primarily three dimensional. Each wheel is roughly 8x8x3 inches. The wheels are round so the bike will be able to move. Each wheel roughly weighs one pound. The aesthetic properties of the component are to look like real Kawasaki wheels, which tie into the rest of the bike. The color of the wheels are black, and have a smooth surface finish, these are both for aesthetic purposes.

Manufacturing Numbers:
80272-0801-01-3
80272-0801-01-3
80272-0801-02-3
80272-0801-02-3

Manufacturing methods

Manufacturing methods used to make this part:

- Blow injection molding

• Material choice highly impacted the manufacturing method because the wheels are made entirely out of ABS plastic. Blow molding is an ideal manufacturing method for the commercial production of hallow plastic parts.

• The round shape of the wheels is not just a simple circle. The ridges on the wheels make the spherical geometry slightly complex. A more complex geometry would require a method like injection molding that allows for a more flexible geometric component. Blow molding would be used instead of a process like turning because blow molding is more efficient and commercially friendly.

• Parting lines and ejector pin marks are present on the wheels, which are common indentifying characteristics of the injection molding process. There are also holes present on the top of each wheel that indicate blow molding was used. The holes on the wheel are where compressed air passed through during the molding process.

• Economically, there is an added cost to individually make each wheel by blow molding. Molding is an efficient way to be able to mass produce a particular plastic component.

• For societal purposes it is necessary to create wheels that are geometrically similar to those on real motor vehicles. If the Kawasaki KFX is going to look like a legitimate bike, specific geometries and details must be added to the wheels. Injection molding allows for a more complex geometry to be created.

• The environment is relatively unaffected by the injection molding process, because the mold can be reused. This reduces the amount of excess waste material that could be released into the environment.

Material Choice

Impact of the Material Choice:

- Manufacturing Decisions

• Plastic can easily be molded to fit a variety of geometries, so it is ideal for creating a medium-sized component with relatively complex geometry. It is also a lightweight material with a decent degree of strength. Plastic is economically cheap to obtain and manufacture commercially.

• The specific chemical properties of the plastic ABS gives the bike the structural support it needs. ABS plastic is a terpolymer plastic made from acrylonitrile, butadiene, and styrene monomers. Acrylonitrile and styrene provide adequate chemical resistance while butadiene adds impact resistance. Since the wheels will be coming into contact with a variety of rough surfaces (along with general environmental conditions), they need to be strong. The wheels will also be handling a lot of load, so impact resistance is essential.

• It is evident that the company does not take into account the effects of plastic on the environment. Plastic is not easily recyclable, yet it is widely used in the production of fisher price components. The front plate is mass produced as a necessary component to the Kawasaki KFX, being made completely out of non-degradable plastic.

• Globally, plastic is an easily accessible and widely used resource. It is not difficult to get enough plastic to be able to commercially distribute the components of the Kawasaki KFX.

• Economically, plastic is cheap. Specific types of plastic are more expensive to create than others because of their chemical makeup and strength to weight ratio, but melamine plastic is relatively inexpensive. This also allows for the overall consumer price of the product to be lower.

• Socially, fisher prices needs to make sure they are creating their product component within manufacturing safety regulations, like the amount of lead that is present in the plastic.

Nylon Lock Nut

Functions: Holds components together, by locking components together. The nut will function in every environment the Kawasaki will.

Form:
The lock nut is shaped like a hexagon, and because of this, is axis-symmetric. The lock nut is primarily three dimensional. It is roughly 1x1x.5 inches. The lock nut is shaped like a hexagon so it can screw together and lock parts together. The part roughly weighs 4 ounces. This part has no aesthetic properties, as the part was not meant to be seen by the user. The component is a silver color, and has a smooth surface finish, this is for neither aesthetic or functional reasons.

Manufacturing methods

Manufacturing methods used to make this part:

- Die Casting

• Material choice highly impacted the manufacturing method since the nut is made from stainless steel. Die casting is a method specific to metals. Die casting allows for specific geometric shapes to be created, which is essential for the nylon lock nut. If the geometry of the metal nut is not correct, it may lose functionality when the nylon is inserted.

• Die casting is typically good for small and medium sized parts, and a more complex geometry can be obtained. While a nylon lock nut does not have a very complex geometry, it is an essential component that needs to be manufactured at a high volume. A nut is typically used more than once in a product, and the Kawasaki KFX has 3 lock nuts alone.

• If observed closely, parting lines can be seen on the nut. Parting lines are characteristic of die casting. The nut itself also has a good surface finish, which is one advantage and mark of die casting.

• Economically, there is a general large initial cost to make a die. But since metal nuts are a common component of countless products, they are easily mass produced. Metal nuts are inexpensive to make because they can be produced at such high rates via die casting.

• The environment is relatively unaffected by die casting, because the mold can be reused. This reduces the amount of excess waste material that could be released into the environment.

Material Choice

Impact of the Material Choice:

- Manufacturing Decisions

• Metal for commercial purposes is easily available, at a relatively cheap cost. The stainless steel that is used for a nylon lock nut is strong enough to hold individual components together and maintain functionality despite loads.

• The properties of stainless steel and nylon are needed for this small component to function. Stainless steel is an alloy of steel, making it rust and corrode less easily than regular steel. Resistance to corrosion is necessary for general purpose of a metal nut, because it is essential that everything is continuously held in place for the duration of a product’s lifetime. The nylon segment of a nylon lock nut gives the nut a strong resistance to vibration. Nylon plastic is made of polyamides, which makes a very strong, durable plastic. Since the nuts are placed under the load of the bike and are subjected to continuous movement, a resistance to vibration is also necessary.

• Although nylon plastic is not easily recyclable, stainless steel is. The mass production of stainless steel nuts takes the environment into account by having a recyclable quality.

• Globally, steel is an easily accessible resource. Because it is such a highly mass produced metal, companies tend to use steel in a variety of components (like nuts). Nylon plastic is also found in abundance.

• Since steel is produced so frequently and in great quantity, it is very cheap. The manufacturing of nylon lock nuts is relatively inexpensive due to the fact that both steel and nylon are cheap materials.

• Socially, fisher prices needs to make sure they are creating their product component within manufacturing safety regulations.

Steering Column

Functions: Connects the handlebar component to the body of the bike. The steering column also adds structural integrity to the bike. It acts as an interface between the passenger and the desired directional motion of the wheels. It does this by turning the wheels when the user turns the column. This component functions in all environments that the bike would.

Form:
The steering column is generally shaped like the letter T. The column is axis-symmetric. It is roughly 3x2x(1/12) feet. The steering column is primarily three dimensional. This component is shaped like the letter T so the user can easily turn the bike. The steering column roughly weighs 3 pounds. An aesthetic purpose of the steering column is to look like a real steering column from a real Kawasaki. The steering column is silver, and has a smooth surface finish. Both are for aesthetic reason, to make the power wheel look like a real Kawasaki. Manufacturing Number: J8472-Q505-01-1

Manufacturing methods

Manufacturing methods used to make this part:

- Injection molding

• Material choice highly impacted the manufacturing method because the front cap is made entirely of a hard, glossy plastic called polypropylene. Injection molding is an ideal manufacturing method for the commercial production of plastic components.

• The shape of the front cap is relatively complex, in order to effectively mimic the realistic motorcycle elements. Molding allows for more complex geometry to be created.

• Parting lines and ejector pin marks are present on the front cap, which are common indentifying characteristics of the injection molding process.

• Economically, there is an added cost to individually make each front plate component by injection molding. Molding is an efficient way to be able to mass produce a particular plastic component.

• The environment is relatively unaffected by the injection molding process, because the mold can be reused. This reduces the amount of excess waste material that could be released into the environment.

- Die Casting (extrusion)

• Material choice highly impacted the manufacturing method since the actual handlebar component is made from steel. Die casting is a method specific to metals. Because both the handlebar component and steering column do not have highly complex geometries, the extrusion process was used to form the bar.

• Die casting is typically good for small and medium sized parts, and a more complex geometry can be obtained. Although the handlebar does not have a very complex geometry, it does need to be widely produced in an efficient amount of time. Die casting metals with simple geometries is a relatively fast and simple process. Extrusion is used to create objects with a fixed cross sectional profile, which would be the diameter of the handlebar component and steering column.

• Economically, there is a general large initial cost to make a die. But because of the simple geometry of the steering components, these parts are continuously in demand, and the benefits will eventually outweigh the startup cost.

• The environment is relatively unaffected by die casting, because the mold can be reused. This reduces the amount of excess waste material that could be released into the environment.

Material Choice

Impact of the Material Choice:

- Manufacturing Decisions

• Plastic can easily be molded to fit a variety of geometries, so it is ideal for creating a medium-sized component with relatively complex geometry. It is also a lightweight material with a decent degree of strength. Plastic is economically cheap to obtain and manufacture. The steel that is used for the bars is also commercially cheap and easy to manufacture.

• The specific chemical properties of the plastic melamine make it a decent type of plastic to be used for the front plate of the bike. Polypropylene is a thermoplastic polymerized from porpene, making it a very strong, dense, plastic. A strong plastic is needed for the front cap component because the cap covers the welding section of the steering column and handlebar component. Polypropylene is one plastic that fisher price distinctively uses throughout their lines of products. Steel provided a good strength to weight ratio, allowing the handlebars to withstand physical environmental constraints while still being relatively lightweight.

• It is evident that the company does not take into account the effects of plastic on the environment. Plastic is not easily recyclable, yet it is widely used in the production of fisher price components. The front plate is mass produced as a necessary component to the Kawasaki KFX, being made completely out of non-degradable plastic. Steel, however, is a highly recyclable metal.

• Globally, polypropylene plastic is an easily accessible and widely used resource. It is not difficult to get enough plastic to be able to commercially distribute the components of the Kawasaki KFX. Steel is also mass produced worldwide and is very easy to incorporate into a product that is intended to be widely manufactured.

• Economically, plastic and steel are cheap. Specific types of plastic are more expensive to create than others because of their chemical makeup and strength to weight ratio, but polypropylene plastic is relatively inexpensive. This also allows for the overall consumer price of the product to be lower.

• Socially, fisher prices needs to make sure they are creating their product component within manufacturing safety regulations, like the amount of lead that is present in the plastic.

Battery Circuit

Functions: converts chemical energy to electrical energy, by producing electrochemical reactions. The battery circuit can perform in most environments, unless the environment is too hot or too cold.

Form:
The general shape the the battery circuit is a rectangle. It does not have any notable properties, and is not axis-symmetric. It is primarily three dimensional. The battery circuit is roughly 4x3x1 inches. The components shape is connected to the function it needs to perform. It has to be the right size to fit in the bike, and has to be the right shape to convert energy. The component roughly weighs 6 ounces. The battery circuit is black, tan, and green, and has a smooth surface finish. Both are because of the way they were made, and not for any functional or aesthetic purposes.

Manufacturing Number: 74287

Manufacturing methods

Manufacturing methods used to make this part:

- Drilling

• Material choice did not have a major impact on the manufacturing process. In this case fiberglass was the material that was drilled into. If the material was plastic, wood or even metal, drilling could still have been used
• The shape of the battery circuit does not have a major impact on the manufacturing process. The component could have been drilled even if the battery circuit was a circle instead of a rectangle.
• There are four holes, one at each corner of the battery circuit which suggests that the component was drilled into.
• Economically, drilling is relatively inexpensive. Because drilling is a fast process, each part can be drilled without costing a company valuable time. The drill bits used in this process eventually need to be replaced, but only after a great amount of use.

- Etching

• Material choice had a major impact on the manufacturing process. When the circuit board is dipped in the corrosive solution, the exposed copper dissolves, and the copper that was protected by the resist pattern remains. So this type of manufacturing process will only work when copper is used.
• Shapes did not have an impact on the manufacturing process. In this case the circuit board is a rectangle; any other shape would not have a major impact on the process used.
• The shiny copper pattern on the circuit board is evidence that this component used etching.
• Economically etching is the cheapest way to achieve this desired result. Other methods can not only cost more, but also take more time. This is why etching is the most common method
• Etching has an effect on the environment. The solution that dissolves the copper is harmful to the environment. If the solution is not properly disposed of it will have a negative effect on the environment.

- Soldering

• Material choice had an impact on the manufacturing process. The solder applied to the circuit board must be a certain material for the circuit board to work properly.
• Shape did not influence the manufacturing process used. In this case there was only one way to manufacture this part, so shape had no effect on the decision.
• The method of soldering used is the cheapest way the part could have been manufactured. Therefore the manufacturing process was largely impacted by economic factors.

Material Choice

(epoxy, fiberglass) Impact of the Material Choice:

- Manufacturing Decisions

• The fiberglass used in the circuit board can be formed into any design or shape. Fiberglass is ideal for creating a flat rectangular board. It is strong and lightweight. Fiberglass is relatively inexpensive and easy to obtain.
• Fiberglass is made up of many extremely small fibers of glass. It is commonly used in circuit boards for two major properties. Fiberglass makes a good thermal insulator, which is important in circuit boards. Fiberglass also has a large tensile strength, which is important so the circuit board does not break.
• Since society discovered that asbestos causes cancer, fiberglass has been a popular alternative. Because of this discovery, society has used fiberglass at much greater volume. The safety of fiberglass had a major influence on the material choice.
• Globally, fiberglass is an easily accessible and widely used resource. It is not difficult to obtain enough fiberglass to make a small circuit board.
• Economically fiberglass inexpensive compared to other materials of the same strength. If the fiberglass makes the power wheel cheaper to make then the company can sell the product at a lower price.
• Manufacturers of fiberglass can use recycled glass, which makes the fiberglass in the circuit board more environmentally friendly. Which, in a larger scheme, makes the entire product more environmentally friendly.

Component Complexity

Complexity of each Component:

Complexity of the component interactions:

For the complexity of component interactions, the scale is designated as follows:

Low complexity: the component does not interact with more than one other component on the bike, or it does not interact with anything other than the bike and the environment.

Medium complexity: the component interacts with 2-3 other components of the bike, or is interacts with both the environment and bike simultaneously.

High complexity: the component interacts with 3+ components of the bike and responds to the environmental interactions.

Solid Modeled Assembly

For the Solid Modeling, we used the CAD package named "Solid Works". The very first reason to choose this software is because its easiness in using it and moreover, its great features. Apart from other CAD packages like Auto CAD, and Pro-E, Solid Works leads in the user-friendliness.

For the 3D modeling, we chose the Front Wheel assembly which include the wheel, front axles, and washer. The Front wheel assemble is the main part of the bike which maintains the direction of the bike. The assemble is connected with the two wheels with the axles and the washer.

The 3D model of the components can be seen in the figure below:-

Assembled Model:

Engineering Analysis

Engineering analysis is a method by which engineers to analyze key components of a product. Engineering analysis can be used in the design or testing stages of the design process. Like the process below engineers use a mathematical approach to determine the likelihood of failure in a component. Engineering analysis is one of the most important parts of the design process, as it saves time and money.

Problem Statement
The rear axle of the Kawasaki KFX holds together the motor gear box, gear box component, driver component, and both rear wheel components. If the rear axle is bent enough the power will no longer work. It is important to know how much force will bend the rod, if the force required is too small then the axle needs to be built stronger. We will figure out how much force will cause the back axle to bend.

Diagram for the System

Assumptions

The rear axle is made from steel
The young’s modulus of elasticity (E) for steel is 200 Gpa
The axle is 0.25 kg (approximate value from picking it up)
The axle is 0.635 m (L)
A 1 cm deflection (φ) will cause the power wheel to fail.

Governing Equations
F = 48EIφ/L^3 I =1/12mL^2

Discussion

The axle in this problem was not attached to the power wheel. So the force needed to bend the axle is the maximum force the axle can take. However when the axle is attached to the power wheel, other components will take some of the force off of the axle. This means the axle would be able to take a greater force than the one that would be calculated in this experiment. Therefore the estimate for force would be a liberal one. To get a more conservative answer, one would have to repeat the calculations with all of the power wheels components in the equations. To determine axle geometry, engineering analysis can be used. One can set up a problem and use calculations to determine what geometries will work. Engineering analysis can also be used to determine the material choice of the axle. Because different materials have different modulus of elasticity, the final answer will be dependent on the material choice.

Design Revisions

Wheel Material
Plastic Wheels have been used in Kawasaki KFX to mainly lower the cost of production of the product. Since plastic is cheap worldwide, it is easy to manufacture the wheels from plastic. However, with the wheels made of plastic, the bike loses its grip on a wide variety of surfaces. Mud can get stuck in between the wheels, which stops the vehicle from moving forward. The tires can become damaged if the rider continuously accelerates on uneven surfaces. While ABS plastic is the ideal type of plastic to be used for the wheels, plastic itself gives the product functionality limitations. An alternative to using plastic for the wheels would be rubber. Rubber wheels would be most costly to produce but they would have a broader social impact on the rider. The product would be able to travel on a more extensive range of surfaces, rather than just an even paved road. By using either rubber or plastic, the environment is taken into little consideration. Plastic is a difficult material to recycle, and the unique properties of rubber make it difficult to recycle as well. Changing the material of the wheels to rubber would have a positive social impact on the user, but the environmental impact remains unchanged. Economically rubber wheels would cost more than plastic wheels, because plastic is easier to produce. Rubber wheels would create a better friction interface between the bike and the ground, making it easier for the bike to stop in an emergency. Plastic wheels do not provide as much friction and have the possibility of slipping on certain surfaces. Rubber wheels would increase the overall safety rating of the bike.

Addition of an On-Off Switch
An on-off switch will increase the functionality and safety of the bike. The bike only has an accelerator, which also functions as a type of break pedal when lifted. If an on-off switch is added, it would provide an additional means to ensure the bike can easily accelerate or stop. This would be useful in the event that the acceleration pedal remains stuck while riding. Instead of not being able to safely stop the bike, an off switch could act as an alternate breaking system. This design revision has an essential social impact, involving the safety of the child using the bike. An on-off switch could be added to the design of the handlbar component where it would be easily accessible in case the break pedal malfunctions.

Addition of a Battery Meter
The Kawasaki KFX has a 12V battery, which means that the bike can easily run for about 3-4 hours before the battery needs to be recharged. Since this is a children's toy, 3-4 hours of battery life is enough for a child to get a reasonable amount of enjoyment out of the bike. But it would helpful to have a meter that displays how much batter life is left, similar to a gas gauge. Adding a battery meter to the bike would require additional electrical components at a cost to the manufacturer and company, but it will be socially beneficial. If the user is aware of how much battery power remains, they will be able to accurately charge the battery when necessary and potentially extend the battery life. Extending the life of the battery would give the product a greater usable lifetime, and there is less of a possibility that the consumer would need to buy a replacement battery in order to extend the life of the product.

References

1. http://www.electric-scooter.ca/atv/affordable-power-wheels-kawasaki-kfx-ninja-ultimate-terrain-traction.html
2. http://www.howstuffworks.com
3. http://www.fisher-price.com/us/powerwheels/product.aspx?pid=38097