Gate 1

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Product Management

Work Proposal:

Our group will work collectively to achieve the goals we set; in addition to working as a group there will be individual assignments as well as assignments requiring two or more members to work together towards completing that assignment.

For the disassembly stage of our project our Chief Mechanic, Communications Leader, and Researcher will work together in disassembling the line trimmer while organizing the parts and taking photographs of each part of the disassembly process. The Project Manager and the Record Keeper will carefully record the steps of the process while cataloging all parts relevant information. The assembly process will be very similar to the disassembly process regarding the roles of each member.

After our cosmetic inspection of the line trimmer it has become apparent that the sizes for all fasteners follow the English system. Judging solely from the exterior of the line trimmer the tools required for the dissection will be: socket set, allen keys, and phillips/flat head screw driver. For organization and cleanup detail our group will need a magnetic tray, zip lock bags, markers, a cleaning solution, and paper towels. We estimate the disassembly will take about 3 to 4 hours, and the reassembly will take about 6 to 7 hours. These time estimates take into account physical all processes such as, disassembly, and reassembly, work such as ,cataloging, organizing, and photographing each step.

Upon receiving our product we had been notified by the previous owner that it did not start. The reason it is non-operational is unknown, and our group was unable to identify the reason simply by inspecting the external features of the line trimmer. If the line trimmer is damaged significantly internally this may complicate the dissection and reassembly significantly. Also another factor is the age of the product, we have found that the line trimmer was manufactured in 2003 and had been sitting unused at Hector’s Hardware (previous owner) since May 2012. This may have resulted in corrosion of the line trimmer's internal components. Summary of capabilities:

All of our group members have experience with lawn equipment, basic hand held tools, and reading technical drawings and instructions. However our group only has several members with significant experience working with complex systems such as cars, RC cars, or computer hardware and not all of our members have extensive analytical skills that technical courses such as Statics, Dynamics, and Mechanics of Materials provides. Another shortcoming is our groups ability to create technical reports, this course is the first course which required the utilization of technical writing skills.

Management Proposal:

Our group plans on managing the work by:

•Meeting as a group several times per week.

•Delegating individual work to be completed before meetings.

•Creating/revising outlines and drafts as a group prior to submitting a final copy.

•Leveraging wireless instant messaging via smart phone (whatsapp group chat).

Our group plans to successfully complete the project requirements by:

•Planning scheduled meetings that will be held several times per week.

•Effectively using the time during meetings to be productive.

•Assigning an even share of individual work to each group member.

•Setting due dates for group and individual assignments that must be met.

Point of Contact

Jon Roche – Communications Leader – Email:

Group Meeting Schedule

Day Time Place
Tuesday 5:30-7:30 Dissection Lab or Greiner
Thursday 5:30-7:30 Dissection Lab or Greiner
Saturday/Sunday TBD Greiner Hall

Group Members:

Member Strengths Weaknesses
Courtney Scott -Good managing skills

-Task oriented


-Never used wiki before

-Technical writing


George Melero -Machining experience

-Extensive experience with tools-Extensive work on SolidWorks

-Material analysis


-Basic Math Skills


-Never used wiki before

-Time Management

Jonathan Roche -Experience with tools

-Research analysis

-Never used wiki before

-Technical communication

Behzad Rustemi -Organization

-Time management

-No prior experience with disassembly

-Never used wiki before

-Basic Math Skills

Matthew Hervan -Basic analytic skills

- Good with computers

-Never used wiki before

-Time management

Gate 1 – Project Planning:

The group will be working together during the initial product inspection to gather the necessary information relating to the product archaeology. After the initial inspection each member will be assigned a specific section from the product archaeology to add to the wiki page.

Gate 2 - Product Dissection:

For Gate 2 our group will be split into two sub groups where the Chief Mechanic, Record Keeper and Communications Leader will work together to dissect, catalogue, document and photograph each step. The Project Manager, and Researcher will work together to create the wiki page’s step by step guide on the disassembly of the line trimmer. After the dissection the Chief Mechanic and Researcher will work together on the “Ease of Disassembly” section of table 1 and the Communications Leader, Record Keeper, and Project Manager will work together on the “Document the connection of subsystems” portion of table 1.

Gate 3 – Product Analysis:

In Gate 3 the workload will be mainly an individual effort where each member will focus on a specific section of the product archaeology and eventually compile this information into the wiki page. The roles of the members will be as followed:

•Chief Mechanic – Component Summary

•Record Keeper – Product Analysis

•Communications Leader – Engineering Analysis

•Researcher – Table 1 questions

•Project Manager - Table 1 questions

Gate 4 – Product Reassembly:

Similar to Gate 2 the group will be split into two sub groups where the focus of one subgroup is to reassemble the line trimmer, document the reassembly, and photograph each step. The focus of the other subgroup will be to work on the “Mechanisms” and “Design Revision” portion of Gate 4.

In the even that there is a discrepancy within the group the group member(s) are encouraged to discuss their issue with the rest of the group during meetings or in group chat. If necessary the matter will be settled by process of voting, the side with the majority of the votes will ultimately have the power to make or not make a decision regarding the issue.

Product Archaeology

Development Profile

Economic Concerns


-Correlation of affordability with the quality of the product.

-Average user should be able to afford the product.


-String Trimmer must be costly enough for Craftsmen to make a profit.

-Correlation between Cost of Materials vs. Sale Price.


-People won’t want to buy a product that requires a lot of maintenance

-This includes changing the blade/nylon string and fuel consumption.

Fuel Efficiency

-Gas is expensive.

-More people would buy the product if it didn’t use a lot of fuel.

Global Concerns


-What type of consumer is targeted?

-Urban vs. Suburban consumer.

-Gas String Trimmer is more convenient in a very large yard.

Fuel Emissions

-Emission standards will be different in different areas.

-California and China may have two completely different emission standards.

-Product will need to be more environmentally friendly in areas like china due to high pollution rates.

Compactness of Design

-Must be compact enough so consumer doesn't have trouble storing it.

-Consumers who live in China will have much less space to store string trimmer than someone who lives in Georgia.

Noise Volume

-Consumers who live in tighter areas will require to the string trimmer to be less loud than consumers who live in open areas.

According to the owner’s manual, the product contains United States/California emissions standards. Therefore, the Craftsmen 358.791580 was meant to be sold in the United States. The Craftsmen 358.791580 is intended to shape the edges of the consumer’s lawn. It is meant to make one’s neighborhood look clean and tidy while not causing a large disturbance noise wise and environmentally. The product is not only made to give the consumer aesthetic pleasure while looking at their lawn, but also the surrounding society to give them a sense of comfort. It was intended for ease of use so that the consumer could be proficient with minimal prior experience. Also, safe enough so that any consumer above a certain age limit would be able to use it without hurting themselves.

Usage Profile

The Craftsman Weedwacker 32cc gas line trimmer is a handheld power tool intended for the use of lawn care. This product was designed for the average individual to use for their personal home. “For occasional use only,” is clearly printed on the front of the line trimmer’s owner’s manual. Craftsman’s objective of printing this on the front is to inform the purchaser of this product that it is not meant for continuous use, as for example, a landscaping company may need.

The Craftsman Weedwacker 32cc gas line trimmer was designed to tackle several different tasks. The line trimmer is a complement to a conventional lawnmower, because their main objective is to do the jobs that the conventional mower cannot reach. Such jobs are listed in List 1. An additional job that the line trimmer can accomplish is to act as a sweeper. Using the rotating line as a fan, the trimmer can sweep away small debris. Even with all the different jobs this line trimmer can do, no additional steps have to be taken for it to go from one task to the next. All tasks can be performed with its regular setup.

Tasks Preformed by a Craftsman Line Trimmer

1. Trim-To put into a neat and/or orderly condition by means of clipping, pruning, paring, etc.

2.Mow-To cut grass, grain, weeds, etc.

3.Scalp-To cut away or tear the scalp from.

4.Sweep-To clear or clean dirt, litter, or the like.

List 1: Different jobs of the Craftsman Weedwacker 32cc gas line trimmer


Energy Profile

The Craftsman Weedwacker 32cc gas line trimmer uses three types of energy to accomplish its goals. They are mechanical energy, thermal energy and internal energy. The mechanical energy is in the form of kinetic energy, which is used for the actual cutting. The thermal energy is the heat created from the operation of the engine, and is used to keep components such as the oil at the proper density. The internal energy is the energy gained from the breaking of the molecular bonds in the gasoline used to power the device.

In order for energy to enter the line trimmer, it must first be put in physically. The first input of energy comes from the user. The second input of energy is chemical, and the user must insert that chemical. The chemicals needed are unleaded gasoline and two-cycle oil must be purchased. The user must mechanically pull the pull cord to send the engine through a combustion cycle. This input of mechanical energy is used to get the gas flowing through the engine, so the internal energy of the gasoline can be used. The internal energy of the gasoline is transformed into mechanical and thermal energy by the engine. The gasoline is mixed with air inside the cylinder. The air/gas mixture is compressed and ignited and, the explosion transforms the internal energy from the gas into thermal energy warming the engine and mechanical kinetic energy that is transferred to the driveshaft. The driveshaft transfers this energy to the prop, which uses the kinetic energy to perform the desired task.

Complexity Profile

Complexity Description
1 Does not have moving parts or complicated manufacturing processes.
2 Does not have moving parts but was complicated to manufacture.
3 Contains a few moving parts and somewhat complicated manufacturing processes.
4 Contains many moving parts and has complicated manufacturing processes where tolerances are not very high
5 Contains many moving parts and has complicated manufacturing processes where precision is necessary for the product to work.
Assumed Part Complexity Description
2 Stroke Engine 5 This is the power source of the trimmer; the engine has a crank shaft, pistons, connecting rod, block and cylinder head. All of these parts are moving very close to each other and the contact surfaces need to be smooth to act as a bearing and the parts have to meat very high tolerances for the engine to work correctly.
Carburetor 4 This is what feeds the engine fuel to get power; it is a non moving block that has a valve to control how much air goes through to the cylinder. The carburetor uses the Venturi effect to draw gas in to the engine this have to be within certain specification for the Venturi effect to work.
Drive Shaft 2 This does not have high tolerances it is composed of a wire with more wires wound around it back and forth multiple times this way when one direction of rotational force some of the wires contract and some expand this cancels out and you are left with rotational force.
Ignition System 3 This is what makes the power for the spark plug to spark, there is a magnet on the fly wheel that is in line with top dead center of the engine and it passes by the magneto which is a coil of wires this causes a current that is sent to the spark plug that ignites the gas.
Clutch 5 This part is how the engine engages the drive shaft; it has shoes on pivot points that are held down with springs. At a certain RPM the centrifugal force is grater then the spring force so the shoes go out wards and contact the clutch bell this friction connects the crank shaft to the drive shaft.
Cutter Head 4 This is where all the energy made is used to perform the desired task; the rotational force from the drive shaft is put through a set of tapered gears in order to get the actual cutting head at the right angle to cut grass comfortably.
Safety Guards 1 These are protective plastic parts that cover the dangerous components to keep them away from the user.

Material Profile

Visible materials- From what we can see the string trimmer is made up of plastic for the handle, covers and guards. The long tube that connects the engine to the cutting head is made of steel and the engine is made of aluminum.

Assumed materials- From the parts that we assumed in the quality profile we can expect to find steel for the internal parts brass for the small components in the carburetor, other than those parts the rest of the materials are visible from the outside.

User Interaction Profile

The user interfaces with the product by using it to trim the edges of a lawn. Pulling on the starter rope so that the engine may begin starts it. The user would then grip it and can begin trimming the edges of the lawn.

The interfaces of the string trimmer are very intuitive for the user. The product was designed by Craftsmen taking into mind ease of use for the consumer. A starter rope consists of a handle to let the user know that they must pull it in order to start the engine. The design of the string trimmer is made to be held away from oneself, so the user would automatically know that they could stand back and let the string trimmer take care of the distance. The two handles are made to provide different uses. The handle at the top of the string trimmer can be more for grip while the handle towards the middle can act as more of a guide. Both of these handles provide great stability for the user and would make it very hard for the user to drop the string trimmer while in use. Once the starter rope is pulled, the string will start spinning rapidly. The user can then intuitively realize that it is now time to start trimming edges. This specific model contains a power switch, so once the user is finished using it, they can flip the clearly labeled switch off.

The Craftsmen 358.791580 is very easy to use from a consumer standpoint. Once the starter rope is pulled, the string trimmer is used in more of a “point-and-shoot” type of fashion. The consumer would basically aim the trimmer towards the desired edges, which would not be difficult due to great stability from the two handles, and the string trimmer can take care of the rest. The trimmer is also easily able to be turned off at any point. All the user must do is flip the switch off. The user may then easily store the string trimmer once completely finished with it due to the thin and compact design.

Regular maintenance is required for this string trimmer. This includes changing the gas in the fuel tank, and changing the nylon string in the bottom. Both of these are very easy for a basic user to do. Changing the gas in the fuel tank is extremely intuitive for the user to be able to do. Changing the nylon string can also be intuitive. However, the user may look in the owner’s manual for instructions if they would like to. The cleaning of this product could also be an issue, as it can get very dirty from the lawn excess and gas. However, this is also a very basic maintenance factor for the average consumer. Some of the maintenance factors that could be slightly more difficult for the average user would be changing the air filter. A specific type of air filter would need to be purchased. It could be found inside the owner’s manual along with instructions on how to change it. Overall, the maintenance required for the Craftsmen 358.791580 is not very difficult for the average user, and more on the easier side of the spectrum.

Product Alternative Profile

There are many products which can perform the task of a weed whacker but the question of whether or not they are a suitable alternative depends on the amount of time you can spend and how meticulous you are when using an alternative. Some of these alternatives are shears, scissors, and a lawn mower.

Scissors and shears are a common place item which most homeowners own which allows for a savings in time and cost. Most homeowners own a lawnmower if they considered buying a weed whacker so cost would be less of an issue. If using one of these alternatives the time to complete a simple task would be exponentially higher and the cut would most likely be much more ragged. The other issue is that an edger and lawn mower don’t always fit into the places that a weed whacker does which creates issues. While these alternatives can perform the same job as a weed whacker, they do not compare well. Scissors and shears are a household item which can be used to cut things. They are not a specialized tool that is used to cut a specific type of grass. The lawnmower and edger are specialized tools which can be used in certain cases where space allows. When comparing these alternatives the lawn mower would be able to cut grass at a much higher rate and have a much more even cut. Its main problems come in when discussing cost and size, it will not be able to cut in some situations. Scissors and shears would never be used as an alternative unless it were completely necessary. They would take huge amounts of time to perform a task which should take a few minutes. The only advantage they hold is their size and cost which are both extremely small. The difference in cost is high when comparing scissors and a weed whacker but the amount of time could make up for this drastic change quickly. The lawnmower would be more expensive than the weed whacker but that is because it is also a specialized tool but on a larger scale for a larger task.

The only factors that would play into a case where you needed to use one of these alternatives economic and global. If a person was unable to afford a weed whacker or its up keep than they would be forced to use something else. Also you environment lays out the path for what you need to properly maintain your land. In some cases a weed whacker is unneeded and other tools are.