Group 20 PPR
From GICLWiki
Contents |
Preliminary Project Review
- The purpose of the Preliminary Project Review is to take a look back at our work and management proposals and see if they are working well, as well as provide a step by step guide for taking apart the HP Printer. The Disassembly Procedure details how the printer was taken apart, the Disassembly Reflection discusses what was found during the dissection, and the Causes For Corrective Action looks back at the initial plan proposed by the group and makes changes to that plan if necessary.
Disassembly Procedure
- The disassembly of our printer took approximately three and a half hours over two separate days. Day one occurred on October 19, 2009, and encompasses steps one through twenty. Day two occurred on October 26, 2009, and encompasses the remaining steps twenty one through thirty three. Total time spent on each day was two and a half hours on day one and one hour on day two. Each step required to disassemble the printer is detailed below in Table 2: Disassembly Procedure, and the difficulty was measured using the following table, Table 1: Disassembly Difficulty Levels.
| Difficulty Level | Description of Level |
|---|---|
| 1 | *Minimal effort needed to complete step, only one attempt necessary. * A person with no knowledge of product could complete step |
| 2 | *Some effort required to complete step, possibly more than one attempt necessary if unfamiliar with product. *A person with little or no knowledge of product could complete step |
| 3 | *Active effort required to complete step, as step may need to be thought through to be performed correctly. *Possibly more than one attempt necessary to complete step if step is not thought through properly or timing of step is incorrect. *Pieces may be hard to remove properly as they were not intended to be taken apart easily. *A person with little knowledge of product could complete step. |
| 4 | *Quite a bit of effort required to complete step, as step requires some thinking and strength to be performed correctly. *Possibly more than one attempt necessary to complete step if step is not thought through properly, timing of step is incorrect, or strength required to complete step is not used on the first attempt. *Pieces may be hard to remove properly as they were not intended to be taken apart easily. * A person with some knowledge of product could complete step. |
| 5 | *Maximum effort required to complete step, as step requires thinking, timing, and strength to be performed correctly. *Possibly more than one attempt necessary to complete step if step is not thought through properly, timing of step is incorrect, or strength required to complete step is not used on the first attempt. *Pieces are difficult to remove properly as they were not intended to be taken apart easily. * A person with some knowledge of product could complete step. |
| Step # | Process | Tools Used | Difficulty | Picture |
|---|---|---|---|---|
| 1 | *Power on the printer *Open lid so print head assembly comes into view *Disconnect power cable so print head assembly does not move back out of view |
None | 1 |  |
| 2 | *Remove both ink cartridges from print head assembly by lifting up teal clips. | None | 1 |  |
| 3 | *Remove two Torx 10 screws on top of printer casing. | Torx 10 Screwdriver | 1 |  |
| 4 | *Turn knob and remove back panel. | None | 1 |  |
| 5 | *Remove paper tray from front. | None | 1 |  |
| 6 | *Reach inside from of printer and disengage clips attaching the top cover to the bottom, then do the same for the back. *Slowly pull cover off of printer, as other parts will still be connected to top cover. |
None | 3 |  |
| 7 | *Disconnect panel with buttons from the case by pulling the clips on either side toward each other. *Rotate the panel with the buttons so the panel can fit through the opening in the case, then seperate the panel from the case. *Wires connected to panel can be disconnected by slowly pulling them away from the panel. |
None | 2 |  |
| 8 | *Lift out parallel port and USB port cover. | None | 1 |  |
| 9 | *Remove two screws holding in silver bar on top of printer. *Lift out the silver bar. |
Torx 10 Screwdriver | 1 |  |
| 10 | *Remove the two screws holding in the large motor on the left side of the printer. *Gently remove the belt and click the motor out from the back. |
Torx 10 Screwdriver | 2 |  |
| 11 | *Remove screw holding on the metal plate near the power adapter. | Torx 10 Screwdriver | 2 |  |
| 12 | *Remove control board next to left motor by removing the screw holding it in place. | Torx 8 Screwdriver | 1 |  |
| 13 | *Remove second motor (also on left side) by removing two screws. *Detach the wires from both motors. *Also remove metal clip with rollers next to motor. |
Torx 8 Screwdriver | 1 |  |
| 14 | *Disconnect ribbon cable on both ends (from print head assembly and circuit board). | None | 3 |  |
| 15 | *Remove screws from silver rod. *Rod and print head assembly can now be lifted out in one piece. |
Torx 10 Screwdriver | 2 |  |
| 15a | The disassembly of the rod and print head can now occur. *Disconnect thin transparent strip by carefully releasing the strip on each end. *Disconnect the silver rod by popping it out from the frame on each side, and slide the rod out from the print head assembly. *Remove the 6 pink screws from the print head assembly. *Remove the 3 pieces of plastic that were released by the screws. *The wires and circuit boards for the print head assembly can now be removed. |
Torx 10 Screwdriver | 3 |  |
| 16 | *Depress two tabs on the bottom of printer (towards the front) in order to remove plastic tray that guides the insertable paper tray. *Remove paper tray. |
None | 2 |  |
| 17 | *Disengage large spring (covered in black plastic) on left side. | None | 2 |  |
| 18 | *Carefully pull wire connector out of the circuit board. Remove the circuit board from the printer. |
None | 1 |  |
| 19 | *Remove roller cover that has four springs on it. | None | 2 |  |
| 20 | *Pull rollers out through the back of the printer. | None | 2 |  |
| 21 | *Pop out lower right corner plastic guard using a flat head screw driver. *Blue and black wires that are not attached to anything will be exposed- these must be slid back through the small hole into the main part of the printer. |
Flat Head Screwdriver | 3 |  |
| 22 | *Two little white plastic clips holding wires must be detached with needle-nose pliers. *One is on the right, in the front behind the plastic door that was just removed, and the other clip is on the left in the very back, between the internal frame and the plastic back wall (holding blue and white wires). |
Needle-nose Pliers | 3 |  |
| 23 | *Remove two screws on top of black box on the right side of the printer. *Once the top part of the box is removed, the roller, ink assembly, and sponge can be removed as well. *The box itself can then be removed by depressing the two tabs holding it in- one on the top left side of the box, the other on the right. *After removal, detach the gray wires from the little motor on the side of the black box. |
Torx 10 Screwdriver | 4 |  |
| 24 | *Remove the small motor from side of black box by removing screw and undoing clip. *Remove the two gears. |
Torx 10 Screwdriver | 1 |  |
| 25 | *Disconnect the yellow and green wires from the small tan circuit board. | None | 1 |  |
| 26 | *Remove the small metal blocks from either side of metal frame by turning them so they fit through the slot on the frame. | None | 1 |  |
| 27 | *Remove black wing with spring from gray plastic piece jutting out on both sides of the printer by pulling the front of the wing through the plastic frame piece that it is attached to. *Be careful not to bend the springs as the wings are taken out. |
None | 2 |  |
| 28 | *Remove the gray plastic pieces that held the wings by disengaging the two clips on the bottom of each piece and sliding the pieces upwards. | None | 4 |  |
| 29 | *Slide out the small black bar in the direction of the plastic pieces that were just removed. *Slide out the main rollers (a loose spring will slide off as well). |
None | 2 |  |
| 30 | *Remove the blue and white gears on the left side of the printer. | None | 1 |  |
| 31 | *There now remains a black strip of plastic in the back of the printer. *Gently pull the strip forward until it pops out. |
None | 2 |  |
| 32 | *Remove black bar with clips that held the black strip of step 31 in place. | None | 1 |  |
| 33 | *The printer is now disassembled, with only the frame remaining. | None | 1 |  |
Disassembly Reflection
Challenges to Disassembly
- Our group had to overcome a few challenges during our dissection process. One of the main challenges was that the printer was not designed to be taken apart. This is due to the fact that the average user of the printer has no reason to disassemble it. The only parts of the printer that are designed to be easily removed are the ink cartridges (step 2), and the back panel (step 4) in case of a paper jam. A second challenge was the removal of some screws and clips that were in hard to reach places, which we overcame by changing the angle at which we were attempting to remove the screws and clips until we found an angle that allowed us to remove said obstruction. A final challenge was keeping track of the amount of small parts that came out of the printer. This challenge was overcome by organizing all of the small parts in a sectioned box so we knew where they came from.
Fasteners used in the Printer
- The printer is filled with many different fasteners, which make parts of the printer tricky to take apart. The fasteners used are Torx 8 and 10 screws, plastic clips on the outside casing and other plastic parts inside the printer, and white plastic clips to keep the wires organized inside. The Torx screws were the least difficult components to unfasten in the printer, followed by the white plastic clips and the general plastic clips on the printer. The Torx screws were used to hold together parts of the printer that were easily accessible to get a screwdriver into on order to undo the parts. The plastic clips, on the other hand, were used to clip parts together that would have been difficult to unscrew because of their position within the printer. Unsnapping these plastic clips on the casing and removing the internal plastic parts that contained clips was an extreme challenge at times. This is due to the fact that the printer is not meant to be taken apart, so many of the clips are in locations that are very hard to get unclipped, but easy to clip back into place during reassembly. The white plastic clips holding some wires in place were also difficult to remove from the printer, again because they were in hard to reach spots. These white plastic clips were used because, without them, wires would have been scattered throughout the printer with the potential to get caught in moving parts.
Special Tools Required
- The tools required to disassemble the printer are all fairly common tools. Out of the three tools necessary to disassemble the printer, only the Torx 10 Screwdriver may not be readily available at one's home or office. The needle-nose pliers and flat head screwdriver, however, are both very commonly found. Due to the required tools prevalence, we were able to disassemble our printer out of the lab, which gave our group the benefit of not having to schedule the disassembly during lab hours.
Causes For Corrective Action
Schedule
- So far, with one exception, our group has managed to remain on schedule. All three elements of the Request For Proposal were completed on time by each member of the group, and all elements of the Preliminary Project Review are expected to be completed well before the due date in order to assure proper time for the elements to be incorporated into the wiki. We deviated from our schedule only in the product dissection- we had expected to complete dissecting our product on October 19th, but due to unforeseen circumstances (detailed under ”Estimated Duration of Disassembly”) we were not able to finish during our meeting that night and the task was not completed until our next meeting on October 26th.
- Though we have been meeting our targets, we plan to re-evaluate our planned schedule of meetings, as attendance at the previous two meetings has been only three members. Our original plan was to meet each Monday at eight PM in Capen Library- we have since decided that it is more convenient for us to meet in a Governors lounge where we have more freedom to work at any noise level we choose.
Estimated Duration of Disassembly
- Originally, our group anticipated that our product disassembly would take less than three hours. In the end, the actual length of disassembly was closer to three and a half hours due to many problems, some unexpected and some anticipated. We did not expect the printer to contain nearly as many parts as it did in actuality. There were many small electronic components that we did not expect, and even one more motor that we would have ventured to guess. We were correct in our assumption, however, that as the printer was not intended to be taken apart, there were many screws in “inconvenient or hard to reach locations” and plastic snaps that were difficult to disengage. Many plastic pieces had multiple tabs that had to be pressed at the same time or in a certain order if the piece was to be freed.
Tools
- When we began dissection, we used a set of small electronics screwdrivers (Torx 5 through 10) that we had originally intended to use for that purpose. Some of the screws, however, were too tight for the somewhat delicate screwdriver to be effective. We were forced to switch to a much larger screwdriver set which ranged from Torx 10 through 40. Our belief that we had stripped a few screws proved baseless after we began using the tools that better suited our needs.
Group Member Responsibilities
- To date, work has been distributed unevenly between group members. Some of this is due to which skills are needed for the current part of the project- for example, our three-dimensional model designer has little to complete for Gate Two but will have much more work than anyone else during Gate Three. While Group 20 acknowledges this problem, we do not plan on addressing it unless the situation worsens as the workload should begin to balance out by the end of the project. Problems were also encountered due to the lackluster attendance at group meetings- those not present could not be assigned wiki content creation (most of which is done separately by group members and not at group meetings) as they did not have the necessary knowledge or information. Our group hopes to resolve this issue by adopting a more convenient meeting time that all group members will be able to attend.
