Group 7 - Black & Decker Jigsaw Gate 4
As the due date for the last gate approaches so does the date for the final submission. As a group it is crunch time. We took a well deserved break over thanksgiving and have to jump right back into the heat of moment and finish up this project. This is the time where our group will either soar magnificently to success our spiral downwards towards mediocrity. Group 7 has shown that we can work well together in the past and we plan on continuing this trend right up to the last day. Our flight to success hasn’t been all first class and we had our fare share of turbulence and delays. The challenges that our group experienced are listed below.
- Managing Gate 3- The week ahead of Gate 3 was one of the busiest of the semesters for everyone in our group. Each of us had multiple exams leading up to the day the gate was due but we didn’t want the gate to be pushed to the side until late Tuesday night. To compensate with this we decided to have our own due date a day before the Gate was due. This would ensure that the project was completed on schedule and we still had time to put it on the wiki page. Each person pulled their own weight and if someone was struggling, other members would step in. For instance, our product controller was in charge of one part of the gate and when he finished, he realized that our head wiki constructor needed help so he uploaded his part for the head wiki constructor. This saved everybody time and effort.
- Jigsaw Location- To complete Gate 3 different members of the group needed different parts of the Jigsaw at different locations. This created a conundrum because we didn’t want to lose any parts of the Jigsaw. To combat this dilemma, our group decided to keep the Jigsaw at one central location in the Ellicot dorm complex and as members needed parts they could come over and essentially sign the part out. We now have the Jigsaw completed and back in the capable hands of the product controller.
- Work Load Distribution- As the project progresses, it is becoming harder to fairly break up the workload without disrupting the efficiency of the group. The first gate was easy to separate into 5 different parts but the third gate was tougher to do so. For instance, the product analysis from the gate 3 was hard to break up. Once one person did one analysis, it becomes easier for him to do another. Also, this Corrective Action part of Gate 4 is a good example. It would make sense for the same person to do this part who also did the Corrective Action from the last gate. We were able to successfully break up Gate 3. Gate 4 is challenging to break up fairly because there are really only a couple tasks necessary. To combat this we will be working essentially in pairs and people that do less work for this gate will pull more weight in revising the old gates for the final assessment. Only time will tell if this is an effective solution.
- Project Presentation- As a group, we have yet to decide on who will be presenting. With our presentation day set in stone, we know the timetable that we have to work with. There are some obvious choices as to who will be considered to present but we have not held a meeting and actually decided yet. The meeting to decide who will present will occur over the weekend of 12/4-12-5 and we will solidify who and what will be presented. Creating the presentation will be a group effort but it is up to the individual presenters to astound the audience with their knowledge and stylish outfits.
Difficulty Scale Explanation
The complexity rating of each component can be found in the product reassembly table within the reassembly process, also known as Table 4-1. This table provides a complete step by step list of how to reassemble the Black and Decker Jigsaw including a detailed description as to how to correctly input every component so that the whole system flows, what tools are needed to attach each component into or onto the jigsaw, a photograph of said component being attached into the jigsaw, and a difficulty scale rating the difficulty of each reassembly step. The defined scale to each components reassembly is a factor of how complex the reassembly process is, how much time and effort is required to correctly input said components, if or how many tools are required. Our scale was based on a rating from 1 to 10. The rating of 1 being the lowest and therefore a very simple reassembly process, and 10 being intensely complex to reassembly and extremely time consuming. The majority of the component reassembly for the jigsaw was extremely simple, which can be seen as reassembly steps 1, 4, 5, 6, 7, 8, 9, 10, 11 all received a difficulty rating of a three or less. These steps deal with the main components including the motor, wires, trigger, power cord guard, blade guard, grip, gears, housing, and lastly the screws. The reassembly of these components were extremely easy as they were all easily assembled with little time, effort, and force and did not require any tools other than a pair of hands or a number 2 Phillips head screwdriver. Steps 3 and 12 were moderately difficult to reassemble as they both received ratings of 6. Step 3 is the assembly of the moving parts, and must be assembled with more attention to detail, as the slight misplacement of any part will make the whole system flow less smoothly. Step 12 is also moderately difficult as attaching the base plate is the last step in the reassembly process making precision a must, and it is rather time consuming and confusing to attach correctly. Lastly step 2 received the highest difficulty rating of the process as the reattachment of the transmission received a rating of a 9. No tool was needed for this step, it was all done by hand, but it was extremely difficult to gain the necessary access to space within the jigsaw to correctly attach the transmission. All of the gears must be lined up perfectly with the main drive shaft, and multiple components must come together as one functioning unit.
|Step||Description||Tool Required||Estimated Time Required||Difficulty (1-10)||Photograph of Parts Involved|
|1||The motor assembly can be put together very easily, using only your hands. Simply slide the cylinder with the transmission attachment into the hollow cylinder, and they are ready to be placed into the housing.||Hands||0:10||1|
|2||After the motor assembly is placed in the housing, the next subsystem, the transmission, is ready to be attached. First you must lift the smaller end of the motor out of the housing in order to slide the smaller of the two plates onto the drive shaft, followed by the larger. Once this is completed you must slide the offset gear into the larger plate so that the gears line up with the main drive shaft. After this step is completed you may place the motor as well as the transmission back into the housing as one unit.||Hands||2:10||9|
|3||The next step of this process will complete the assembly of the moving parts (except for the trigger). Like before the smaller end of the motor must be lifted to gain necessary access, but after that is done, the blade assembly can be attached. The largest oval on the blade assembly must slide onto the offset gear of the transmission, then the “slides” must be placed into the housing along with the motor and transmission assembly. The slides will fit into the designated openings located near the front of the housing.||Hands||2:30||6|
|4||Make sure all wires are untangled and distinguishable before performing the next few steps. Coming off of the motor are two wires attached to small black boxes. These boxes need to be placed in the square openings towards the rear of the motor, with the larger side of the box facing outward.||Hands||0:35||2|
|5||Next the trigger can be put in place on the handle of the case. Make sure the wires connecting the trigger follow along the inside of the case in order to provide an easier final step.||Hands||0:20||2|
|6||After this, the white and black wires coming out of the trigger assembly must be run along the inside of the housing until the semicircle on the housing is reached. The power cord guard can be placed in this semicircle to hold it in place.||Hands||0:25||2|
|7||Next, the blade guard can be put in front of the housing. Make sure it is oriented the correct way (facing downward).||Hands||0:15||1|
|8||The grip can also be put in place now, on the top of the saw. It fits in similarly to the blade guard.||Hands||0:10||1|
|9||On the bottom of the saw housing are openings for the two plastic gears. Place them in the corresponding openings.||Hands||0:20||3|
|10||Now, all of the internal components of the saw are in the correct positions. Lay the saw on the side, and place the other half of the housing on top. You may have to apply some force, but not too much.||Hands||1:30||3|
|11||There are seven screw holes on the newly affixed housing. Using a number 2 Phillips head screwdriver, screw the two halves together.||Hands, #2 Phillips Head Screwdriver||0:50||2|
|12||The base plate is the last part needed to be attached. This is done by first placing the large rectangle in place, with the larger opening right under the blade guard. Next the smaller rectangle with the wheel must be put in place. The wheel must be above the first rectangle, with the end under it. There is an offsetting in the base plate so this is possible. After these are in place, the screw must be fed into the hole. Using the exposed plastic gear, tighten the screw into place. This is done by twisting the gear in a counter clockwise direction.||Hands||2:45||6|
When the product was originally manufactured it was done in mass production in a factory. We reassembled the jigsaw using our hands and hand tools (No. 2 Phillips screwdriver). We can only hypothesize how the product was originally assembled based on our previous knowledge and research on the internet. First all the parts are manufactured separately. Next all the parts are placed into the plastic shell in a similar way we described in our reassembly process. Then only difference now is that robotic arms are programmed to complete the assembly process using an efficient process to save money and time.
- The first revision our group recommends for the Black and Decker jigsaw is a vacuum intake for saw dust with a bag to store the dust in. This change would add another system to the jigsaw and also consequently cause other components to change also. The input energy to the vacuum would be supplied from the shaft of the motor, utilizing some of its mechanical energy to rotate the fan. There will also have to be some changes made to the shell to accommodate the intake of the dust collector, the vacuum and also an exit for the dust with a way to fasten the bag to the jigsaw. There will be an extra gear transfer from the shaft of the motor to transfer the rotational mechanical energy to the fan that will create suction for the vacuum.
- When considering the four factors in this design revision, there are positives and negatives to this change. First economically the change in design and the added materials will affect the manufacturing cost. This change will be costly, but once the change is made and the jigsaw is manufactured on a large scale the added cost will be from the extra vacuum system which won’t be too costly. The consumer price for the jigsaw, but the positives created from the other factors will increase its appeal to the consumer.
- The change will affect the societal concerns by increasing its ergonomics and safety. The jigsaws added vacuum feature will make cleaning up after use easier and more efficient. Also the respiratory concerns of sawdust inhalation will be decreased from the dust collector. These added features might increase popularity in the market even though the price will be higher.
- Environmentally the this design revision will not change the existing environmental factors of the original design. The production of the jigsaw will have approximately the same carbon emission and the power requirements of the jigsaw will be about the same for the new design.
- The jigsaw can be revised to be battery powered instead of being a corded tool. This revision would lead to numerous improvements and a few setbacks but overall the improvement would be significant enough to outweigh the negatives. In order for this change to be possible the shell of the jigsaw must be modified to have a battery attachment. Also the battery will lower the voltage available for the electric motor so the motor must be modified to have comparable outputs with a battery as with the power outlet.
- The corded jigsaw makes a good power tool because it is cheaper and is able to run longer. The advantage of having a battery powered drill is obviously the portability. Even if electricity is accessible, a cordless drill is more convenient. Having two batteries allows one battery to be kept in the charger at all times, making battery life less of an issue. Removing the cords makes room for a more versatile device that can be used anywhere or at anytime the user chooses. When using a power tool the last thing that the user would want is an accident, a cordless jigsaw eliminate the threat of tripping over the cord and managing high voltage which overall improve the ergonomics. Cordless drills are a good tool to keep around the house for small household jobs. And seeing that this jigsaw is meant to be used mostly in the house a battery would be more suitable. The weight of the saw will be increased but the saw will be resting on a material when in use so the weight is mostly supported by the material.
- Economically the battery powered jigsaw will be a little more expensive but will worth it for the added serviceability of the product. Then changes to the original design will have so initial cost to the manufacturing process. During production the only added cost would be from the battery and the new motor. If the consumer’s price point is raised because of the added battery the increased cost of the jigsaw won’t be a factor.
- The battery might be convenient but recycling the battery when it can’t be recharged will be difficult and will have a negative impact on the environment. With improving recycling technologies and programs, this problem will become insignificant and batteries won’t have much of an impact on the environment in the future.
- When looking at the tasks the jigsaw would have to preform for a consumer our group found an improvement to the design. When the user is making angled cuts in the material s/he is cutting, there is no set scale to determine the exact angle the saw cut is making. Unmeasured angled cuts could pose problems to the user when s/he is working on projects involving differently angled cut materials. To fix this problem we revised the base plate to have a scale for the angle the saw blade is relative to the perpendicular axis of the surface. This revision would be simple and add value to the jigsaws usability.
- The added scale component wouldn't affect the overall design too much which means a low economic impact to its manufacturing. The added cost would be from the initial design change to add in the scale and a way to attach it to the base plate. Also the material the scale is made of and the manufacturing cost of die casting the material would increase production cost. These cost are minimal compared to the original manufacturing cost which makes this revision cost efficient.
- The scale will be marked by degree intervals which can be recognized globally a unit measurement for angles. Although the product is really only designed for sales in North America, the scale would be able to be read by most people in the world.
- The added scale for angled cuts would increase the serviceability of the jigsaw greatly. Before this revision all cuts on an angle were pretty much an estimate. The added component makes the product easier to use and increases its versatility as a tool.
Owen, Bill. "Black & Decker JS660 Orbital Jigsaw Review." Case Mod Blog. Web. 08 Dec. 2010. <http://www.casemodblog.com/?p=6718>.
Dynapod. Web. 08 Dec. 2010. <http://www.dynapod.com/dyna-a-prot.html>.