Group 8 Gate 4
Project Management: Cause for Corrective Action
For the previous submission, the project team decided to put an emphasis on individual effort rather than working together as a team. This was done in order to adequately complete all the work required. Normally it would be more beneficial to work more as a team rather than individually. However the group has significant conflicting class schedules and there are only three group members completing the vast requirements each gate requires. As a result, the individual efforts of each group member during their personal availability proved to be more productive than trying to work together during a small window of time. Group collaboration still continued directly after class on Mondays, Wednesdays, and Fridays to keep communication amongst the group strong.
The main issue during that arose during the process of completing gate four was when the group had to present product revisions to the class on Friday, December 2nd. A presentation for Friday Failure was also required. As a result, the group had to adjust their schedules in order to adequately put together two presentations. Besides the extra work that was required to complete the presentations, the completion of gate four was executed relatively effectively. The group plans to complete gate five in the same manner as previous gates. This will be essential due to the groups conflicting exam schedules during finals week as well.
Product Archaeology: Product Explanation
During reassembly, the same process of dissection can be used in reverse to put the product back together. There are minor differences in the ways it can be dissected for example, the chain brake and chain brake lever can be put on before or after the clutch is put into place. As long as the chain brake is open before either way. In general however, after taking apart and reassembling the chainsaw several time over the course of the semester, the same process is used for both assembly and reassembly.
Many characteristics of how the chainsaw is structured gives clues as to how it was manufactured. For the most part, the product was manufactured the same way as the reassembly. The carburetor and adpater for example shows that they can not be attached to the engine before it is installed because there wouldn't be room to insert the fuel tubes on the bottom of the carburetor and the kill switch lines and choke lever must be installed before the the carburetor and air filter casing go in.
|Step #||Pictures of Parts Needed||Description||Challenges (If Any)||Tools Used and How||Difficulty|
|1||Reattaching the engine block to the chainsaw body. First slide in the piston plates inside the engine block and hold them in by hand while simultaneously sliding in the piston and pushing the engine block down into the body. Flipping the chainsaw body upside down while holding the engine block in place reveals four holes where the four largest screws are screwed in to secure the engine block down to the chainsaw body.||A major challenge of this was trying to keep the piston plates in while sliding the block over the piston. Several times the plates fell out resulting in starting from the beginning. Also the piston must be in axial symmetry with the piston hole in order to get it in smoothly.||Screw driver. The screw driver was used to screw the screws into place. The rest is done by hand.||3|
|2||Muffler Assembly. First place the muffler spacer against the inside of the muffler then place the muffler shield against the muffler spacer. Aligning the two screw holes the two half inch star screws can be screwed in because the muffler shield is slightly threaded. This keeps those three parts together for attaching the muffler assembly to the engine block.||A small challenge arises when trying to keep the muffler plates in line while putting in the screw. One screw must be put in first then rotating the plates in the right position the second screw can be screwed in.||A star screw driver must be used for the screws.||2|
|3||Muffler attachment. This step is attaching the muffler assembly to the engine block on the side opposite of the handle using the same screws used in the muffler assembly. To avoid twisting the structure of the muffler or screws you must alternate between the two screws every few turns until the muffler assembly is securely attached to the engine block.||No challenges presented themselves in this step.||The same star screw diver used in the last step must be used in this step as well because the screws being used are the same as the last step.||1|
|4||Spark Arrestor. This step is completed by taking the small metal spark arrestor screen over the muffler where the exhaust come out over the extruding bolt. Then place the exhaust directer plate over that and secure these two parts down with the small brass muffler nut.||No challenges presented themselves in this step.||A 3/8 inch socket wrench is used to secure the brass nut down onto the bolt extruding from the muffler.||1|
|5||Reattaching the flywheel. In this step the flywheel must be screwed clockwise back onto the crankshaft. Then the large steel flywheel nut must be screwed on over that to secure it down onto the crankshaft.||This step involved no chanllenges.||The flywheel is screwed on by hand but the flywheel nut required a 1/2 socket wrench to screw it down.||1|
|6||Reattaching the ignition mechanism. The ignition mechanism is screwed down to the chainsaw body using two of the common 1 inch screws on the lower left side to the flywheel. The screw holes through the ignition mechanism are elongated to allow for placement adjustment of the mechanism. This allows for the metal arms to be as close to the flywheel's magnets as possible without touching.||The only challenge of this step is securing the mechanism in the right place (as close as possible to the flywheel without touching). This took about three tries of loosening and tightening the screws, a minor inconvenience.||A screw driver is required to screw and unscrew the two screws.||1|
|7||Securing the wires. There is a channel on the side of the engine block, the side where the ignition mechanism is attached, to insert the wires coming out of the ignition mechanism. The wire guard wrapped around the two smaller wires should be centered to provide maximum protection form the engine block. The wire clip is then clipped on to the channel over the three wires, including the one that goes to the spark plug.||No challenges were involved in this step.||No tools were required for this step.||1|
|8||Reattaching the spark plug and spark plug wire. The spark plug must be screw into the top of the engine using a spark plug socket and wrench. Then the spark plug wire is pushed onto the top of the spark plug by hand.||No challenges were involved in this step.||A spark plug socket and wrench are required to screw the spark plug wire down.||1|
|9||Attaching carburetor adapter. The carburetor adapter is attached to the engine block opposite of the muffler by four 1.5 inch star head screws. Before screwing the part down it can be put in place by hand and holds by itself with a built in rubber gasket around the adapter which pressed against the chainsaw body. A small break in the gasket allows the two smaller wire from the ignition mechanism to pass by. Then the four screws can be screwed in.||A challenge in this step is screwing in the screws. The chainsaw body is in the way when screwing the two bottom screws which results in an awkward time securing those two bottom screws.||Star screw driver to screw in the screws.||2|
|10||Reattaching the carburetor. The two fuel lines must be pushed back on the two brass tubes on the carburetor. With the chainsaw aligned so the handle is pointing at you, the fuel line from the primer is connected to the left side brass tube on the carburetor. The fuel line coming from the gas tank is connected to the right side of the carburetor. The carburetor is now slide down onto the adapter over the two bolts extending from the adapter and pushed down against the adapter. The carburetor is later secured down by the air filter casing. The choke lever is then inserted onto the lever controlling the bottom airflow channel.||No challenges were involved in this step.||No tools were involved in this step.||1|
|11||The primer can now be snapped back into place by hand.||No challenges were involved in this step.||No tools were required for this step.||1|
|12||Reattaching the trigger bar. The trigger bar is inserted into the lever controlling the top airflow channel of the carburetor. Then pulling down on the throttle exposes the hole where the the other end of the trigger bar slides into place. The trigger bar holds itself in place.||No challenges were involved in this step.||No tools were involved in this step.||1|
|13||Reattaching the kill switch wires. The end of the black wire is inserted into the bottom part of the kill switch mechanism on the air filter casing into a small hole. The yellow wire is pushed onto a metal male receiver on top of the kill switch mechanism.||No challenges were involved in this step.||No tools were required for this step.||1|
|14||Reattaching air filter casing and securing the carburetor. With the kill switch wires in place the air filter casing can be placed over the carburetor with the bolts of the carburetor adapter passing through the respected holes in the air filter casing. Two small steel nuts are then screwed onto the two bolts coming from the adapter, through the carburetor and through the air filter casing and a small 3/4 inch star head screw is screwed through a hole in the top right of the air filter casing and into the carburetor. This attached air filter casing also pins down the choke lever allowing it to move in only it's intended direction.||No challenges were involved in this step.||A 3/16 socket and wrench is required for the steel nut and a star screw driver is required for the screw.||1|
|15||Air filter reassembly. The air filter mesh can now be placed into the air filter casing and the air filter cover can be snapped onto the air filter casing which holds down the air filter mesh.||No challenges were involved in this step.||No tools were required for this step.||1|
|16||Reattach clutch. The centripetal clutch screws onto the crank shaft counter-clockwise and is only further secured by running the chain saw which tightens the clutch down.||No challenges were involved in this step||No tools were needed for this step.||1|
|17||Reattaching the chain brake lever. By pulling apart the two bottom arms of the lever, it can be placed over two plastic cylinders extruding form the chain saw body which also holds the lever in place.||The force required to pull the arms apart to fit over the cylinders is rather high and presents a minor inconvenience.||No tools were required for this step.||2|
|18||Reattaching the chain brake. By moving the chain brake lever to the right position the chain brake can be pushed into place and secured down by four of the common 1 inch screws.||No challenges were involved in this step.||A star screw driver is required to screw in the four screws.||1|
|19||Reattaching the clutch drum. With the chain brake in place the clutch drum slides smoothly onto the crankshaft over the clutch and inside the chain brake. The larger steel chain washer is slide onto the crank shaft edge in, then the smaller steel washer, then the C-clip is clipped into the groove on the crankshaft holding down the clutch drum and washers.||Pushing the C-clip into place requires excessive force placed in two very specific places at the same time. This took several minutes to perfect before the C-clip was successfully in place.||Two screw drivers were used to apply the force needed to push the C-clip into place.||3|
|20||Reattaching the pull start mechanism. The pull start mechanism is placed over the flywheel and is secured by four common 1 inch screws.||No challenges were involved in this step.||A star screw driver is required to screw down the four screws.||1|
|21||Reattaching the top casing. The top casing is placed on top of the chainsaw and is secured down by three 2 inch partially threaded screws.||No challenges were involved in this step.||A star screw driver is required to screw down the four screws.||1|
|22||Reattaching the chain bar and chain. The chain bar spacer is placed over the two chain bar bolts extruding from the chainsaw body. The chain bar is then placed over the chain bar spacer over the same bolts. Looking at the chainsaw with the handle to the left, move the chain bar as far left as possible. Now the chain can be placed over the chain bar and drive gear. Move the chain bar as far right as possible fixing the chain as necessary inside the channel of the chain bar.||No challenges were involved in this step.||No tools were required for this step.||1|
|23||Reattaching the chain bar tightener. With the chain bar as far right as possible the chain bar tightener can by put in place over the two chain bar bolts. The small hole on the bottom of the chain bar must line up with the tightener tooth sticking out from the chain bar tightener. The chain bar tightener can now be screwed down by two common 1 inch screws.||No challenges were involved in this step.||A star screw driver is required to screw down the two screws.||1|
|24||Securing chain bar knob. The chain bar knob can now be screwed down by hand which holds the chain bar in place after tightening the chain bar.||No challenges were involved in this step.||No tools were required for this step.||1|
|25||Reattaching handle. After putting the handle in place it can be secured down by four common 1 inch screws.||No challenges were involved in this step.||A star screw driver is required to screw down the four screws.||1|
The chainsaw services the home user exceptionally well in its current condition. After a thorough analysis, a few design revisions to the chainsaw as a whole have been suggested to improve the overall functionality of the product. Design revisions were determined with global, societal, economic, and environmental factors taken into consideration.
Design Revision 1: Addition of user warning panel
With societal factors taken into consideration, it is suggested that a notification panel is added to the top of the exterior housing on the chainsaw. This is the optimal position for the panel to be placed due to the fact that minimal debris will come in contact with the panel. Ideally, the panel would be able to run off power generated by the motor. However if necessary, a 9-volt battery can be added to supply the necessary power.
This panel would alert the user if the chainsaw is low on fuel, if the chain bar oil is low, if the chain break is engaged, and if the tension in the chain is inadequate through the use of computer gauges. This is important because it aids the user during operation to ensure optimal performance. If the user is not aware that they are not low on fuel or chain oil, then they risk running out of fuel during operation or damage to the chainsaw as a result of improper lubrication. The low tension notification serves the same purpose because if the chain is too loose, it will not cut properly and can potentially damage the chainsaw as well. The purpose of the chain break alert is to notify the user whether or not the safety is engaged. It is not easy to determine from just looking at the position of the hand guard. So instead of the user fully engaging the engine while the clutch is locked and risking damaging the engine, a notification on the panel can alert the user if the safety is engaged.
- Makes operation easier for user
- Prevents damage to the product
- Increase in cost for redesign and production
- If a 9 volt battery is needed, then an increase in waste will occur from when the battery dies.
Design Revision 2: Production of Left-Handed Version of product
During the analysis, two group members found the current design of the chainsaw to be comfortable to handle. The other group member, found it awkward to handle. It turns out this members issues with the handling were a result of him being left-handed. From these observations, it was determined that a line of this chainsaw could be developed specifically designed for left-handed users. Although the current design is functional for left handed users, its awkwardness makes it uncomfortable to use. This in result raises safety concerns for left handed users. This revision essentially involves reversing everything on the chainsaw. The chain bar would be on the left side as opposed to the right. The top handle would be spun around as well. Since there are more right handed people in the world compared to left handed, the production of the left-handed version would be significantly less.
- Increases safety for left handed users by minimizing awkward handling situations
- Increased production costs for redesign and assembly of left handed version.
Design Revision 3: Addition of LED lights
Although it is not recommended that this product is used at night, there are situations that the user could be in that the lighting is not optimal. It is recommended that two LED lights are added to the top front of the chainsaw. Although no cut is ever so precise that absolute lighting is needed, optimal lighting would increase safety by Allowing the user to clearly see what they are cutting regardless of the lighting situation around them. Ideally, the light would be able to run off power generated by the motor. However if necessary, a 9-volt battery can be added to supply the necessary power.
- User is able to cut wood in various lighting conditions safely
- 9-volt battery needs to be replaced overtime. This increases user operation costs and increases waste from the dead batteries.