Group 16 - DeWalt 4 1/2 in Angle Grinder Gate 4
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<td>Challenging</td> | <td>Challenging</td> | ||
<td>A machine would have fit through the holes and pulled the wires out while a press simultaneously forced the magnet into the housing.</td> | <td>A machine would have fit through the holes and pulled the wires out while a press simultaneously forced the magnet into the housing.</td> | ||
| − | <td>This will be the reverse of the disassembly process, however feeding the wires through the two holes will be a challenge that was not present before. This will significantly increase the difficulty, because the wires must be controlled while the magnet is being pressed in.</td> | + | <td>This will be the reverse of the disassembly process, however feeding the wires through the two holes will be a challenge that was not present before. This will significantly increase the difficulty, because the wires must be controlled while the magnet is being pressed in. </td> |
<td>[[File:Step1.jpg|100px|thumb]]</td> | <td>[[File:Step1.jpg|100px|thumb]]</td> | ||
| + | </tr> | ||
| + | <tr> | ||
| + | <td>2</td> | ||
| + | <td>Needle Nose Pliers</td> | ||
| + | <td>Use the needle nose pliers to take the shorter of the two wires from each electromagnet side and connect them to the lead above the brush spring.</td> | ||
| + | <td>Easy</td> | ||
| + | <td>This step would have been done by hand, the same way in the factory.</td> | ||
| + | <td>This is the reverse of disassembly. No significant deviations.</td> | ||
| + | <td>[[File:Step2.jpg|100px|thumb]]</td> | ||
| + | </tr> | ||
| + | <tr> | ||
| + | <td>3</td> | ||
| + | <td>10 mm Socket, Hammer</td> | ||
| + | <td>Take the bottom shaft bearing (it has a slightly larger interior hole than the top shaft bearing) and replace the rubber coating. Then force the bearing onto the metal nub at the bottom of the drive shaft. It must be forced all the way down (not just to the nub). To do this, place the bearing over the nub, and then place the socket on the bearing, with the drive shaft firmly secured. Then use the hammer to tap the socket until the bearing is pressed onto the nub.</td> | ||
| + | <td>Challenging</td> | ||
| + | <td>This part was shrink fitted on in the factory</td> | ||
| + | <td>This is the reverse of disassembly but will be more difficult because a instead of just forcing the bearing off, it must be controlled and the drive shaft must be stabilized as it is forced back down.</td> | ||
| + | <td>[[File:Step3.jpg|100px|thumb]]</td> | ||
| + | </tr> | ||
| + | <tr> | ||
| + | <td>4</td> | ||
| + | <td>T-5 Torx Driver, Needle Nose Pliers</td> | ||
| + | <td>Realign the plastic brush support over its hole, and screw the Torx screw in to secure it. Now pull the spring back and place it on the plastic ledge of the housing. Then insert the brush into its holder, sliding the wire through its hole. Use needle nosed pliers to connect the lead to the nearest metal slot. Repeat for other side.</td> | ||
| + | <td>Moderate</td> | ||
| + | <td>A machine would have moved the pre-assembled brush into position and then screwed it down. The leads would then be connected by hand at a later point. (All wires would be connected at once)</td> | ||
| + | <td>This is the reverse of disassembly. No significant deviations</td> | ||
| + | <td>[[File:Step4.jpg|100px|thumb]]</td> | ||
</tr> | </tr> | ||
</table> | </table> | ||
Revision as of 16:31, 28 November 2012
Contents |
Introduction
In this phase of the project our group completed our reverse engineering process by reassembling our product and gathering information from the reassembly process. In Project Management our group describes how we have worked through the challenge presented in Gate 3, as well as discussing why our current group structure has prevented further challenges from arising. Once this had been completed our group did the reassembly and created a step-by-step process so that our product could be reassembled without significant prior knowledge of the product. After this our group analyzed the helical bevel gear, one of the primary mechanisms in our product, and considered both its purpose and the equations governing its motion. Our group then recommended three system level design revisions that would improve the overall functionality of the product. All of these can be found under Product Archaeology. Lastly, in Conclusions our group considered all of the information we have gathered over the course of this project in order to make detailed conclusions about the original design of our product.
Project Management
As described in Gate 3, our group's last remaining issue is the attendance of one group member. This member did not attend for the meeting where we divided the assignments for this gate, thereby preventing him from taking on or contributing to any of the gate components. Several times now he has been told when and where the group will be meeting, but he has failed to attend or give a valid reason for missing. Our group divided the work in such a way that we will still complete this gate efficiently, even without this member's help. For Gate 3 this method proved workable, as the workload was not too severe for four people to complete. We therefore have avoided assigning this member important tasks (or any tasks in this case) and will be mitigating the problem through the same means used before. This solution has been an effective method of preserving the overall project quality without severely impacting any of the other members.
Besides this attendance problem, our group has no remaining internal problems. All of the solutions provided since Gate 2 (and listed below) have been effective:
- Not knowing how to use the wiki: Our group's functional knowledge of the wiki has been enough to allow effective technical communication because of the previous steps taken to learn how the wiki works.
- No out of class meetings: While our group does not have regularly scheduled meeting time, we have done well at getting most of the group together when the Project Manager gives a couple days' notice. This has allowed our group to adapt and function in a way that would not be possible if all communication was via email.
- An unevenly distributed workload: With the exception of the aforementioned member, the work has been divided as fairly as possible, with considerations for the amount of work involved in any part taken into consideration. For this gate, the instructor provided a breakdown of the point allotments for each section, which aided our group in assessing how much time each part would entail. We thus were able to come up with a fair distribution of work.
Product Archaeology
Product Reassembly
Product Reassembly
Difficulty Scale
In order to describe the difficulty of each step during the reassembly process our group will use the classifications outlined in Table 1. These classifications don't just consider the time involved in any given step, but also take into account the tools required, accessibility of the parts, required force, and overall intuitiveness. In addition, some of the steps may have required creative approaches as all of the factory tools and machines would not have been accessible when reassembling by hand. Any of these creative approaches are listed under the Challenges section, as they would be necessary for an average user to reassemble the product while only using household tools.
| Difficulty | Description | Example |
|---|---|---|
| Easy | This step was completely intuitive, required minimal skill, involved no excessive force, and took a small amount of time. The average user would not need detailed instructions to perform this step. | Screwing a nut or screw back into its original location |
| Moderate | This step required some planning to perform, involved a difficult hand or tool positioning, needed some force but could still be done by the average person by hand, and/or took a greater amount of time than an Easy Step. A description of the step would be very helpful for a person who had no prior knowledge of the product. | Forcing a series of parts onto a shaft in the correct order. |
| Challenging | These steps were very difficult to perform, either requiring fine work in a hard to reach place, large amounts of force that cannot easily be applied by hand, and/or requiring a creative approach in order to reassemble the part. In addition to a general description of the step in Table 2, Challenging steps will be described in greater detail in the Challenges section. | Replacing a part that was originally shrink fitted on |
Reassembly Instructions
The information in Table 2, in combination with the Challenges section, is intended to give a set of full instructions so that a user not familiar with the product could easily reassemble it. In addition, the original factory methods for assembly are described, as well as comparisons to the disassembly process. These are intended to highlight the ideal methods for reassembly and point out key deviations from the disassembly process for individuals who have greater resources or completed the disassembly themselves respectively. Lastly, pictures of the product at the end of each step are provided so the user can check their work and make sure they have connected the right parts.
- Before beginning reassembly, the following tools will be needed
- Phillips-head Screwdriver
- Torx Drivers:T-5, T-10, T-15
- Needle-nose Pliers
- 3/8" Crescent Wrench
- 10 mm Socket
- Hammer
| Step | Tools | Description | Difficulty | Original Assembly | Disassembly Comparison | Image |
|---|---|---|---|---|---|---|
| 1 | None | Slide the electromagnet into the main housing with the wires towards the bottom. Each wire must go through one of the holes at the bottom of the housing along with the wire nearest to it. The electromagnet will be a very tight fit, and will require a lot of pressure. | Challenging | A machine would have fit through the holes and pulled the wires out while a press simultaneously forced the magnet into the housing. | This will be the reverse of the disassembly process, however feeding the wires through the two holes will be a challenge that was not present before. This will significantly increase the difficulty, because the wires must be controlled while the magnet is being pressed in. |  |
| 2 | Needle Nose Pliers | Use the needle nose pliers to take the shorter of the two wires from each electromagnet side and connect them to the lead above the brush spring. | Easy | This step would have been done by hand, the same way in the factory. | This is the reverse of disassembly. No significant deviations. |  |
| 3 | 10 mm Socket, Hammer | Take the bottom shaft bearing (it has a slightly larger interior hole than the top shaft bearing) and replace the rubber coating. Then force the bearing onto the metal nub at the bottom of the drive shaft. It must be forced all the way down (not just to the nub). To do this, place the bearing over the nub, and then place the socket on the bearing, with the drive shaft firmly secured. Then use the hammer to tap the socket until the bearing is pressed onto the nub. | Challenging | This part was shrink fitted on in the factory | This is the reverse of disassembly but will be more difficult because a instead of just forcing the bearing off, it must be controlled and the drive shaft must be stabilized as it is forced back down. |  |
| 4 | T-5 Torx Driver, Needle Nose Pliers | Realign the plastic brush support over its hole, and screw the Torx screw in to secure it. Now pull the spring back and place it on the plastic ledge of the housing. Then insert the brush into its holder, sliding the wire through its hole. Use needle nosed pliers to connect the lead to the nearest metal slot. Repeat for other side. | Moderate | A machine would have moved the pre-assembled brush into position and then screwed it down. The leads would then be connected by hand at a later point. (All wires would be connected at once) | This is the reverse of disassembly. No significant deviations |  |
