Gate 1 - Group 15 - 2012

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Contents

Introduction

The product that we have chosen to work with this semester is the Skil 7 1/4" Circular Saw. It is tool designed for use in construction and home environments and performs the basic task of cutting materials in a linear fashion. The tool performs this task by rotating a circular saw blade at high speeds in order to subtract material until a complete cut through the medium is created. This project will span over the course of fifteen weeks and will include a complete disassembly, reassembly, and analysis of all the components of the product.

The purpose of this gate was to make an initial assessment of the product and the group members. A work proposal was created and outlines how the group plans to disassemble and reassemble the product in addition to predicting what tools will be necessary in order to perform these tasks. A summary of the capabilities of the group members was made in addition to the shortcomings that they possess. This was important because it would allow the group to pinpoint what would need to be improved in the group members over the course of the semester in order to be successful. A management proposal was also created and lists the names and contact information for each group member. In addition, a plan for group meetings was made which addresses where they will take place, when they will happen, and how they will be managed. Roles for each member were assigned in order to split up responsibilities. A thorough analysis of the product was made without any dissection in order to familiarize the group with the product. In addition, the product was researched in order to point out the normal uses and purposes of the product.

Project Management

Work Proposal

In order to reverse engineer the circular saw, there are several important factors and requirements that must take into consideration. First and foremost, we must have a decisive plan of action to determine exactly how we approach each problem. In order to provide a solid foundation for the rest of the project, this proposal will aim to create a general outline for the procedures we will follow throughout the reverse engineering process.

Disassembly

The dis-assembly of the circular saw will be difficult and our group must proceed with caution in order to make sure that everything goes as planned without any problems. In not, several issues may arise which could jeopardize the success of our project and prevent us from having the capacity to reassemble the saw. Overall, the major steps we will take during the reverse engineering process of our circular saw are as follows:
1. Determine which component to disassemble
Within the outer and inner workings of a circular saw are many different pieces that compose the main structure. Looking from the outside in, we will analyze the structure to determine which parts are the easiest to access. From there, we will decide as a group which piece to remove from the structure. Our decision will be based off an evaluation of the difficulty it will take to remove the part, and how its removal will affect the rest of the system. This stage is expected to take one to three minutes per step depending on complexity of each move. Actions such as removing screws or nuts will take seconds to decide on, where removing the inner workings of the saw will take longer because we must make careful considerations on how each action will effect our ability to remove further parts.
2. Remove the part with the appropriate tool
Although removing a component of a circular saw may sound like a simple task, there are many complications that are involved. In the interest of correctly removing each piece, the proper tool must also be selected to complete the job. After researching the structure of a circular saw, it has become apparent that a variety of wrenches and screwdrivers will be sufficient. Until we actually begin to take apart the circular saw, we can’t be certain of exactly what types we will need. This stage is expected to range between seconds for each step and several minutes for more complicated actions. For example; screws may take seconds on remove, but removing the inner workings of the saw could take several minutes if they are hard to remove or are complex in nature. Some of tools that are expected to be utilized during this step include
Tool Table15.jpeg
Figure 1. Table of Tools
3. Document any vital information
At this point, all that is left is to catalog the part that has been removed. This step is extremely important, because without an accurate account of the part’s characteristics and its relationship with the rest of the circular saw, the assembly stage would be near impossible. Some examples of important documentation are a brief description of the component’s purpose along with pictures that show exactly where it was used. Information such as this will allow us to document exactly how each part is used in a clear and logical manner. As every component is removed, all of this information will be recorded in chronological order and the component will be labeled to ensure optimum organization. This entire process ranges in the amount of time it will take to accomplish. Recording steps of disassembly will take minutes to write down, but compiling all of the information into a form of technical communication could take a long time because many tables and pictures will be needed in order to convey information to the reader.

Assembly

For the most part, the assembly process will follow the reverse order of the process for the disassembly of the circular saw.
1. Examine all documented information
The group will make sure that all of our information from the disassembly is organized in the reverse order so that we can begin to reassemble the circular saw.
2. Connect the part with the rest of the assembly
As we piece the saw back together part by part, it is important to make sure that each part is placed back in its proper position. Using the same tools we used to take the circular saw apart, our group will begin to re-build the structure.
3. Continuously compare system to the original documentation
This final step is basically the solution check to our assembly. Without references back to our original notes and pictures there would be no definitive way to tell whether or not the circular saw has been assembled correctly.

Challenges

Due to the immense complexity of this project, there are many challenges that we will face throughout our project. Unfortunately, there is no way to tell exactly what problems we will face so this will have to serve as a general statement to improve our awareness of potential hazards. One of the most obvious limitations every group will face is time. After analyzing the amount of work and extensive detail required throughout every step, it has become clear that there is no way to set a specific time limit on any aspect of the project. As a group, our best bet is to determine certain time windows within which different aspects must be completed to maintain our punctuality.
It is very important to create a schedule in order to meet all of our deadlines with ease. Furthermore, a circular saw can become very complicated very quickly as the amount of parts being removed builds up. Keeping all of these small components organized and accounted for will certainly be difficult. In addition, there will be a large amount of data to manage and organize considering each part will need a description as well as a photo to sufficiently describe it. Lastly, the fact that our group’s product is a circular saw poses immediate safety risks. This machine is designed to cut through several dense materials with ease and we must not take our safety precautions lightly. Although the power will not be on while we are examining the structure, it is still vital to keep in mind that the blade is very sharp and that we must demonstrate extreme caution as we proceed.

Group Personnel Evaluation

Personnel Evaluation15.jpeg

Figure 2. Personnel Evaluation Table
In order for the group to be successful, some of the skills possessed by group members will need to be developed. In addition, some shortcomings will need to be addressed before the semester continues to ensure that the group operates as best as possible. Firstly, members who are skilled with CAD may wish to review how to perform basic commands so that they will be ready to create models when the time comes. This is critical so that time will not be spent trying to re-learn material while it needs to be immediately applied. Apart from that, the best that the group members can do is to make sure that they stay organized and continue to perform well in technical communication. An apparent difficulty present in the group is that roughly half of the group members commute and the remainder do not live near each other on campus. This will be challenging because it will not allow the group to meet whenever we need to at our convenience, and so attendance will be a critical factor that needs to be improved among group members who skip classes. Attendance is critical because it will be used to plan the group's next moves and coordinate efforts. Members with heavy course loads will manage their time effectively so that they have time to study and do well in other classes and perform their duties in this class.

Timeline Plan

Timeline Plan.jpeg

Figure 3. Timeline Plan Table
Though each gate has two weeks in between each due date (with exception to gate 3), there will be a predetermined due date for each group member to have their work completely done by. This will typically be two or three days before each due date. This will be done so that the person compiling all of the information into the wiki will have enough time to perform their task and edit any work. This will ensure that the work will be presented as best as it possibly can. These dates have not been predetermined yet because the group will need to meet and discuss when the work will be due by taking into consideration the amount of material that must be completed. This information hasn't been released yet, so it is not possible to determined due dates yet.

Management Proposal

Work Division

Each week the group work will be divided based on a point system. Higher priority and more involved tasks will receive more points than less demanding assignments. A single task can receive no more than five points, with one point being the minimum. The total number of assignment points for the week are summed and divided by five. This gives the approximate number of points that each person will receive for that week. Group members are allowed to volunteer for any task. Priority is given to those that have knowledge in that particular field or are willing to put in the time to learn and do it correctly. Also each week a compiler will be assigned based on a rotating schedule. The compiler for that week/assignment is in charge of collecting all of the individual assignments from the other group members and putting them together. The compiler is also in charge of the initial quality control check by making sure that each assignment is followed correctly. Any minor mistakes the compiler is obligated to fix themselves, however major errors allow the compiler to return the assignment to the corresponding group member for a redo. A pre-deadline for every assignment will be set a few days before the actual due date so that any errors can be properly fixed. Conflicts will be resolved by discussing them as a group and deciding on an appropriate course of action.

Meeting Times

The purpose of each meeting will vary. After gates are assigned, meetings will be held in order to split up work and to discuss when dates for working in the dissection lab will take place. In addition, group members will discuss parts of each gate and decide on what kind of material will need to be included in them. Goals will be outlined at the beginning of each meeting so that they will stay on track and ultimately accomplish something. In addition, tasks will be outlined for each group member at the end of every meeting so that they will have something to contribute at the next one. Activities will be managed by running down a list of what needs to be accomplished at each meeting. Every group member is free at 5:00 p.m. (directly after class) Monday and Wednesday. General/emergency meetings will be held in the government documents section of Lockwood Library. These meetings are expected to last from at least fifteen minutes to possibly hours depending on the amount of material that needs to be discussed. Technical/work sessions will be held in the dissection lab. Each group member has been assigned a specific title to help with the ease of communication and lessen confusion throughout the course of the project. Every group member is expected to attend unless a legitimate excuse is given. Decisions will be made by group discussion and compromises will be made if needed in order to arrive at a conclusive plan of action. In the event that there is conflict, the group will meet and discuss the problem at hand and possible solutions. Ultimately, group conflict will be emailed to the professor so that there is a record of behavior for the offending party. This is necessary in case a group member(s) proves to be detrimental to the group later in the semester. If you need to get in contact with our group please contact the Manager, Nicholas Grieco, at nlgrieco@buffalo.edu.

Group Roles

Group Manager/Supervisor: Nicholas Grieco (nlgrieco@buffalo.edu)
• In charge of final quality check for all assignments
• Will assign tasks to those that do not show up to class/meetings
• Regularly check progress with all group members
• Emergency point of contact for all group members if they encounter any problems
Co-manager/Documenter/Wiki Technician: Theodore Nalesnik (trnalesn@buffalo.edu)
• Will document and outline the group’s progress and findings during the project (in depth).
• Will be responsible for editing and putting information into the wiki page.
• Log group ideas and activity during meetings for future reference
• Can take responsibility for one or all of the Manager’s tasks if needed for whatever reason (like an illness)
Modeling Expert: Joshua Beres (jjberes2@buffalo.edu)
• Responsible for the majority of the CAD modeling assignments
• Will also assist with other parts of project that need to be completed.
Dissection Technician: James Pullano (jamespul@buffalo.edu)
• In charge of proper storage/dissection of the hand saw. Including any research that might be needed for complete dissection (how to access welded or permanently molded seems)
• Required to document non text progress during the dissection process. (Making quick sketch models, pictures, videos, animations, flow charts, etc)
Communication Director: Colin Mutton (colinmut@buffalo.edu)
• First point of contact for all group members
• Responsible for group wide email communication
• Will facilitate the distribution of important documents to other group members, via hardcopy or electronically.
• Checks to make sure everyone will be on time for group meetings/ any auxiliary problems.

Product Archaeology: Preparation and Initial Assessment

Development Profile

The Skilsaw is a handheld circular saw manufactured by Skilsaw Inc [3]. Its design is similar to that of the first worm-drive portable circular saw which was developed in 1923 by Edmond Michel, who later went on to form Skilsaw Inc [3]. During this time, the key economic concerns were being able to offer an affordable, yet powerful tool with a long product life. The tool was relatively new during that time period and the common person only had so much money to spend on buying a cutting tool. It was necessary for the circular saw to be affordable if there was a plan to expand so that it could be used by the common person. In addition, the global concerns at the time were being able to find materials to construct the Skilsaw and finding a region to distribute in where many consumers could have access to it. Since the objective was to expand the market, the only way to bring the product to the customer was to make it accessible in places like hardware stores or stores specializing in construction. The Skilsaw was intended to be sold in the United States and Canada [3]. Its development and distribution impacted the consumer by allowing the everyday person to have access to a powerful tool that could make precision cuts at different angles. The size of the Skilsaw also enabled the home owner to be able to use a powerful saw in a location such as a garage without having to need access to a machine shop. In addition, it impacted society by offering an ergonomic power saw as an alternative to a handsaw. The Skilsaw also features a guard to protect the user from its blade and a trigger that will cancel power in the event that the user loses control of it.

Usage Profile

The intended use of the Skilsaw is to make precision cuts at various angles in different materials [1]. The circular saw would be required where there are long and straight cuts that need to be made on an object within a space that may not be accessible to something such as a table saw[1]. For example, a long and wide board of wood needing to be cut down the middle at a construction site would require a circular saw because it is powerful enough to cut and portable enough to carry in that type of environment. It may be used in a home setting or for professional use [1]. The common person may find this tool to be invaluable because it is a small, affordable, and maneuverable tool that can make powerful cuts. It may also be used professionally by users such as construction workers because it is designed to make cuts with better precision than another product such as a handsaw. In addition, both home and professional users may benefit from the portable nature of the saw. It only requires that the user have an outlet nearby to draw power from and may be displaced as far the power cord will reach [1].

Energy Profile

The Skilsaw powered by electricity in the form of a 120V alternating current and has a 13 amp motor that generates 2.3HP [3]. Electrical energy is imported into the system by a cord which connects from an electrical outlet to the back of the Skilsaw. These electrical outlets are typically found in residential and construction settings wherever there is access to power lines. In this process, the electrical energy is converted into mechanical energy through the motor, which is used to rotate the blade. There are also other forms of energy expressed during this process such as thermal energy from the friction of the blade and acoustic energy from the sound of the blade cutting through material and the internal parts operating.

Complexity Profile

Complexity Profile15.jpeg
Figure 3. Circular Saw Complexity Profile

Material Profile

There is a hard plastic found on the handle, which is shaped in such a way that the human hand can grab and guide the tool. The plastic is also shaped in a cylindrical way around the back of the tool, which houses the motor and the inner workings of the saw. Various metal torx screws can be seen along with a foot that is flat on the bottom to allow the user to slide the product across the surface of the material that the user is cutting. There also is a cord to bring an electrical current to the product which is assumed to be metal on the inside to conduct electricity and is covered in plastic in order to insulate it from its operating environment.

Plasticg15.jpg

Figure 4. Plastic on Circular Saw
Materials that are present but not currently visible would be the motor and the internal gears which are used to convert electrical to mechanical energy and ultimately spin the saw blade. Electrical wire must be present inside of the hand saw to transfer electrical energy to the motor where it will then be converted to mechanical energy. It is expected that these materials are metal in order to be able to conduct electricity.

User Interaction Profile

To use the product one adjusts the plane to the type of cutting necessary, holds down the safety lock button and depresses the lever to turn on the saw [2]. The interfaces on the saw are intuitive, easy to use, manipulate, and understand. The product is, with basic knowledge of intended purpose, very easy to use. The product only requires that the user keep the trigger pressed to allow power to be delivered to the saw and that they guide it correctly alone the cutting path. Regular maintenance is required for safety reasons. A majority of the maintenance concerns making sure the saw blade is regularly replaced (as teeth fade, making for poor and dangerous cutting potential) that all electrical cords are functional and without short (to avoid saw uncontrollably starting or stopping) and to make sure the safety measures (safety lock, as well as guards) are functional and in place [2]. Maintenance is, again, very easy with basic knowledge of the products intended purpose. If the saw becomes dull, the user will need to replace it or take it to be sharpened. In the event that a power cord becomes damaged, the user will either need to patch the breach or have the manufacturer replace it. In addition, lubrication may be needed to be added to the point where the saw rotates in order to keep it operating with minimal friction.

Product Alternative Profile

Alternatives to the Skilsaw include, but aren't limited to, hand saws (hack saws primarily), table saws, and miter saws. These are all rough alternatives, as a circular saw is designed for a specific range of utility. The aforementioned other saws can do some of the things circular saws are intended for, but none do all. The advantages are, relating to the previously stipulated point, based on what sort of utility you expect out of the saw. Miter and table saws offer more precision in the sense of straight cuts but at the drawback of mobility. Advantages of a hand saw would be increased precision in sharp angled cuts with a severe drawback in cutting time. Disadvantages of miter and table saws include large size, lack of mobility, and the inability to do curved or angled cuts easily. The main disadvantage of handsaws includes time consumption as well as less clean cuts. The alternatives are not worth it as a circular saw is designed for a specific range of cutting utility, and excels in doing so, while other saws are meant for other ranges of use. Table and miter saws tend to be significantly more expensive than a circular saw. Hand saws are purchasable for less than the cost of a circular saw.
Tool Advantages Disadvantages Picture
Circular Saw Fast and powerful cutting, low cost, and very portable. Not as precise, only cuts straight lines, and limited to reach of user Circsawg15.jpg
Miter Saw Greater precision and cuts in a much straighter line Inability to do curved cuts, large size, lack of mobility, and cut is not as clean Mitersawg15.jpg
Table Saw Greater precision,cuts in a much straighter line, and can produce much cleaner cuts. Inability to do curved cuts, very large size, lack of mobility Tablesawg15.jpg
Figure 5. Tool Comparison Table

Citations