Gate 2 - Product Dissection (Group 24)
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[[Group 24 - Cyclo HBB Parallel Shaft Helical Gearbox with Cyclo Reducer Input]]
[[Group 24 - Cyclo HBB Parallel Shaft Helical Gearbox with Cyclo Reducer Input]]
==Project Management: Preliminary Project Review==
==Project Management: Preliminary Project Review==
Revision as of 03:16, 26 October 2012
Project Management: Preliminary Project Review
Our original work plan was not as effective as we thought. At the onset of the dissection we severely underestimated to complications that we would run into. Our plan was to all remove the external bolts in order to remove the casing cap that housed the love joy connection and the reducer, remove the casing cap, and simply slide the bushing out of the shaft. However, we were unaware that the bushing was threaded into the shaft. After applying quite a bit of force we determined that it must be threaded and we came up with a new plan of action. We did not have access to the proper tools in order to do this, so we improvised by clamping the bushing in place and spinning the reducer so that it would unscrew itself. At that point in the project we were not aware that the machine shop was even an option at our disposal. After a long, frustrating, and brutal hour we were able to unthread the bushing from the shaft.
Once we managed to remove the bushing we began running into even more problems. Based on documentation that we found from the manufacturer, we expected that the rest of the shaft assembly would just side out once the bushing was removed. This was not case. After hammering it with a rubber mallet and getting absolutely no results we realized that we needed to try something else. Next, after contacting our Professor we determined, with guidance, that we needed access to a press to make any progress. We then scheduled and appointment to use the machine shop the following Monday. Using the machine press made the whole process got much more simple. We pressed the shaft out of the gear which removed the top bearing from the shaft as well. Once this was done we were able to slide the gear right out of the casing and begin removing the reducer input mechanism.
We used the press one more time to remove the reducer input mechanism, but it quickly became apparent that, once again, we didn’t know how to move forward. We needed to remove a bearing that had been pressed into place and we could not use the press to remove it. With the help of our professor we were able to remove the bearings using a bearing puller, a tool that we had never even heard of before. Without the help of these tools we would have injured someone in a hopeless effort to finish our dissection.
Work Plan Assessment
It was amazing how simple it was to finish taking apart the Helical Buddybox (HBB) once we started using the correct tools. As the dissection trudged forward it quickly became apparent that our original dissection plan underestimated the amount of time, the amount of work, and the overall complexity of the product. Our initial assessment didn’t even include the possibility of using a press or a bearing puller, both of which were integral to the products dissection. We credit our obstacles to our own ignorance about tools and our lack of knowledge about machinery. During the first gate we predicted that it would take about six hours to dissect our project. It turned out to take eleven hours in total, something that we were not expecting but we had enough for site to plan accordingly. This left us with amble room to take into account the error in our judgment. Furthermore, none of us had ever used a press or even heard of a bearing puller before we started work on this project. Without these tools we would never been able to dissect the product.
Originally we did not lay out our group responsibilities in an effective manner. At the start of the dissection process there was a lot of confusion about what needed to be done, when it needed to be done, and who would do it. We resolved this issue by having a group meeting and laying out, exactly, what we would each be responsible for in the lab. We concluded that, as the lab manager, Yuri would be responsible for the documentation and organization of all of the parts. This included taking photos, laying out the parts in an orderly manner, storing the parts in separate organized bags, and listing the parts that were removed. Next, as someone with more tool knowledge than the rest of us, we concluded that Jason F. would be responsible for cleanup and tool management during the dissection. This proved to be incredibly helpful because we ended up using a lot of tools and we created quite a mess. Having somebody responsible for this not only lead to an orderly, clean dissection, but it also benefited the other groups using the lab. In retrospect this was one of our strongest accomplishments, considering that it was often difficult to find the tools that we needed. We always made sure to leave the lab in a better state than we found it. Finally, Hao, Patrick, and Jason D. were responsible for the majority of the actual dissection with help and guidance from Yuri and Jason F. However, this process did not account for time management issues that we faced.
Seeing as though our meetings were restricted to lab time, we needed to communicate regularly and discuss who could meet when. We soon discovered that everybody would not always be available during lab openings. This was one of the major issues that we faced In order to resolve this, while getting the work done at the same time, we came to the conclusion that we would do a revolving dissection in which we would meet on alternating lab days to account for the days that different people could not show up. This proved to be very effective because it made it easier for everybody to get involved without getting in the way of one and other.
Moving forward it is apparent that our schedules will continue to conflict with one and other. We plan to lay out specific times that we can all meet to get work done, well in advance. By doing this we hope to increasing the transparency of the group thought process, decreases the amount of times that group members need to miss, and alleviate most of pressure put on group members during the scramble the night before a gate is due. Our goal is to make sure that no one group member suffers unjustified workloads at any time, especially considering that we each have other pressures coming from different courses and outside sources.
Product Archeology: Product Dissection Step-By-Step Process
In this section we will clearly explain the step-by-step process used to take apart the HBB. The reader must keep in mind that certain components of this module were not meant to be taken apart (contrary to manufacturer documentation), that is they were either permanently pressed or fixed onto a certain component. Also, some manual hand operations and common knowledge of tools will be necessary.
The HBB is a subsystem to a larger system of components used to run conveyors for at least 20 hours a day. This unit requires maintenance between 500-1000 hours of use that mainly consists of draining and lubricating the two sections of the HBB, the gearbox and the reducer. Due to this design the removal of seals had to be improvised with tools that were used to either pry or puncture the seals for removal.
Before disassembling our product we were informed that a seal had broken within the gearbox, so proper procedures were taken in order to minimize mess/oil spillage and protection of our hands from oil and burs. Paper towels and gloves were used to handle and clean all parts.
Part 1: Casing Disassembly
Step 1: Cast Iron Guide
- By using a 13mm wrench we removed eight (8) bolts and washers that secured the guide to the high-speed end shield. These were difficult to be remove, but with enough force the bolts finally rotated. The bolts and washers were placed aside on a piece of paper and marked step 1. The guide was then removed from the gear box by raising it up vertically off of the gearbox.
Step 2: Draining Oil
- The oil plugs can be easily identified by their yellow tips. We first removed the plug from the gear box with a 22mm socket wrench, placed the plug on a sheet of paper marked
- We then inverted the module to drain as much oil as possible into a bottle for proper disposal. This was difficult only because the product is heavy and awkward to use.
- This process is then repeated for the oil plug located beneath the reducer, also easily identified by its yellow tip.
- Two (2) lock tight screws that were used as an input for re-lubrication were also removed with a 5mm Allen Key(2-2A) and a 7mm(2-2B) and used to drain oil as well. Both lock tight screws were placed onto the sheet of paper marked Step 2.
Step 3: Side Plate
- Now that the oil has been drained the side plate to the gear box assembly can be removed. Using a 6mm Allen Key we removed the eight (8) bolts and washers that held the side plate to the gear box. The side plate was then placed along with the 8 bolts and washers on a sheet of paper marked Step 3.
- We noticed at this step that there was still an excessive amount of oil within the unit and at this point we once again tipped and drained as much of the oil as we could from the side.
Step 4: Taper Bushing
- Six(6) thumb tightening screws were then removed from the bushing and placed on a sheet of paper marked Step 4.
- After initially trying to rotate the bushing with a vice grip clock-wise, counter-clockwise, pulling the bushing vertically out of the gear box and removing the seal underneath the gear box by first puncturing it with a flat head screw driver and then prying it off to get a better idea of how the parts were assembled, we referred to an instillation guide provided by SM Cyclo on how to properly install the bushing. We then followed that step by step guide in reverse to remove it.
(SOURCE: Taper Grip Bushing Installation Guide)
- The installation guide did not address our problem. We finally decided to use the torque from the machine to unscrew the bushing by applying a vice grip to the reducer and another to the bushing. By rotating the reducer in one direction and the bushing in the opposite direction the threading to the bushing finally gave way and removal became easy by unscrewing the bushing, by hand, from the gear box in a counter clock wise motion. The bushing was then placed on the sheet of paper marked Step 4.
Step 5: Cyclo Reducer Input Section
- The reducer input section was easily removed by lifting it off of its support rods that were attached to the gear box. Further dissasembly of this component is needed and thus was placed on the side on a sheet of paper marked Step 5.
Step 6: Shaft
- In this step our objective was to remove the centrally located shaft that supported the main gear within the gear box. To do this we had to remove the seals from the bottom of the housing that would allow the slotted shaft to be removed from the bottom. By again, using a flat head screw driver we pried the initial seal. After this was removed, we found that the second seal was already broken and fragmented within the ball bearing casings. These fragments were set aside for further analysis inside of a plastic zipper bag marked seal fragments.
- We then removed the ball bearing from the casing around the shaft underneath and above the gear. We believe that some of the ball bearing broke apart as well due to the ease of removal. We will analyze this further this in a later section. The ball bearings were placed in a separate plastic zipper bag and marked bearings.
- We then proceeded to use a mallet to remove the shaft from the gear box. The mallet did not supply enough force for the shaft to be removed from the bottom of the casing. A machine press was then used by propping the gearbox on top of two(2) steel plates and applying the press to the shaft. The cylinder then slid out of the bottom along with an inner ball bearing casing. Both the shaft an casing were brought back to the lab and placed separately on a sheet of paper marked Step 6.
Step 7: Gear
- After the shaft was removed the gear slid out of the side plate. We then wiped down the gear of all oil and placed it on the side on a sheet labeled Step 7.
Step 8: Pinion
- To remove the pinion from the pinion shaft, which is located underneath the reducer fitting, we first removed the seal underneath the gearbox housing which then exposed the shaft that is fixed to the pinion. Using a machine press we pressed the helix shaped pinion out of the pinion shaft. The ball bearing casing underneath the pinion gear also came out. This casing was then pulled off of the pinion shaft and both components were placed on a sheet of paper marked Step 8.
Part 2: Reducer Disassembly
Step 1: High-Speed Shield
- To detach the shield from the reducer housing we used a machine press to press out the shaft through the Lovejoy jaw coupling. Once the shaft was pressed out the shield, its housing ring, the Lovejoy, and the shaft with gears and bearings were all separated and placed on a sheet of paper marked Step 9.
Step 2: Ball Bearing Casing
- To remove the ball bearing casing, a ball bearing puller was used to pull the casing up the shaft opposite of the gears. Consequently the lower bearing casing also came off the shaft. The two(2) gears remaining on the shaft also came apart after the initial ball bearing case was removed. All components on the high speed shaft were held in place by a key slot. These pieces were set aside onto a sheet of paper marked Step 10.