Group 3 - Kawasaki Compressor - Gate 4

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Figure 1: Kawasaki Compressor [2]


Contents

Project Management


At this point in the project, all five group members have learned each other\'s strengths. This has been helpful in time management and productivity. We can assign certain assignments to certain members based on their abilities. One of the struggles our group had through the entire semester was finding a time where all five members could be together. Based on life\'s circumstances and conflicting schedules, we have only been able to meet a couple times. However we have started to become more productive during those meetings with equal contribution from each member. Our "contact" plan we established before helped us to make solve any problems we may have had with scheduling or misunderstandings with meeting times and places. We had to initiate the plan a couple times and that resolved the problem of members being uninformed about scheduled meetings. In initiating the plan, we made sure that each member was made sure of the scheduled meeting taking place by having our project leader contact each member at the time that we decided to meet, and then also having a reminder sent out shortly before the actual meeting to assure that everyone would be at the meeting. By having so many checks in our contact plan, we are able to make sure that each person gets the message about the meeting from more than one source, so that each member is sure that there is a meeting taking place. By doing this, there was less time wasted trying to contact each member so that more time could be spent on actually working on the project.

Being more careful with meeting times though did not necessarily help with the actual work our group had when we came together. At times during meetings, we would become distracted or disorganized as to what each member should really be working on and the amount of time that should be spent doing such a task. We were not always on the same page as a group, which would potentially make the meetings more disorganized and unproductive. As time went on though, we started to be able to work together more efficiently, as we all began to focus more on the task at hand so that we could reach our goal quicker. At times, we would have to remind each other to continue to stay focused on the project and make sure that we all get our work done as efficiently as possible. Checking in on each other\'s progress and making sure that everyone stayed on task was important because of the fact that it was hard to find time to meet as a full group. So while at times we may have become a little more disorganized, we were able to come together as a group and work towards our common goal in helping to complete this project as efficiently as possible.

Product Archaeology


The product archaeology is a complete overview of the process involved in assembly, its comparison to the disassembly process, as well as a complexity rating and explanation for each step within in the process.

Reassembly Overview


During the product reassembly, all group members were present. The assembly itself took roughly 2 hours. During the cold winters of December, we took our compressor into one of the member\'s garage to reassemble. Using numerous tools and various methods, we were able to assemble our compressor back to the condition from which we took it apart. The reassembly was followed in the exact opposite order of the disassembly. In disassembly, we begun by removing the air filter and the motor shroud and ended by removing the electric motor. When reassembling, we started with the electric motor and ended with the shroud and air filter assembly. Many of the systems required a specific order of disassembly/reassembly in that a part could not be removed unless its precursor part was removed. The piston, for example, could not be removed until the cylinder was taken off and the expansion ring and wrist pin were removed. Reversely, the piston needed to be installed in the exact opposite way, in which the wrist pin and expansion ring were placed on, and the cylinder after. The compressor has a fairly simplistic design, but complex enough that its disassembly/reassembly order has few options to choose from.

A step by step process on how the compressor was reassembled is located below. Also provided in the description are the difficulties of assembling each component and the tool(s) used.

Product Reassembly Difficulty Scale


During the reassembly process, we found that some components did not go back together with as much ease as others. For this variable difficulty, we defined a quantitative scale to rate the difficulty of each components reassembly. This scale is based on a point system. These points were given to each component based on specific parameters given to accurately judge the difficulty of the components reassembly.

The scale is based on a point system where;

  • 1 point is given per number of tools used to fasten/ tighten the component.
  • 1 point is given per number of alignments the component requires to properly attach.
  • 1 point is given per every extra group members needed to properly reassemble the component when more than one person is needed.
  • 1 point is given per extra force one group member applied to properly reassemble the component.
  • 1 point is given if there are wire connections that need to be made.

The max amount of points a complexity rating can reach is ten, because at that point it is easy to see quantitatively that it is a much more complex part to assemble than a different part which might only have a rating of a two or three. Each rating can be distinguishable from each other because it is easy to see at a lower rating of a two or three, there are less parts to align and connect, so there is therefore a lot less finesse or power which would be needed to put it together compared to a assembly process which has a higher rating of a seven or eight. Those processes which have higher ratings do take a little more time to reassemble. They take some more skill in making sure each connecting part is lined up the way it should be so that the compressor assembles correctly and can therefore function when fully reassembled.

Product Reassembly Process


For each step of the reassembly, a picture or diagram,

Table 1:Product Reassembly
Step Number Our Assembly/Complexity Rating Original Assembly Picture/Diagram


#1 Align the motor with the crank case. The motor bracket needed to be aligned to allow the bolts to pass next to the motor and into the crank case. The wires also need to pass through to reach circuit breaker. The bearings require force to fit into the bracket. Then bolt the motor to the crankcase using 8mm socket.


\'\'Complexity:\'\'
The total complexity for the step is 8. There is a point for extra force, one for aligning the motor and casing, one for the wire attachment, four for each of the bolts, and one for the wrench to attach the bolts.

The bearings were pressed onto the shaft and then pressed into the crank case housing. The coils of wires are then slid onto the magnet. Then the motor bracket was bolted to the crank casing. The entire motor bracket assembly was most likely assembled at another ocmpany and then shipped to where the compressor itself was being assembled.
#2 Attach the fan to motor shaft. Fit the expansion ring around the shaft with pliers, then tighten the screw using a hex head screwdriver connecting the fan to the shaft.


\'\'Complexity:\'\'
The total complexity rating for this step is 3. There is one for aligning the fan correctly, one for the pliers for the expansions ring, and one for the screwdriver for the hex screw.

The fan was slid onto the motor shaft but making sure to gap it enough that it will still spin. The screw was tightened to hold the fan in place and an expansion ring was installed as well.
#3 Attach the circuit breaker to the crank case. Attach the circuit breaker by sliding on the wires. The nut was attached using a 14mm open ended wrench to lock the breaker into place.


\'\'Complexity:\'\'
The total complexity rating for this step is 3. There is one point for aligning the circuit breaker through the hole, one point for the wrench used to attach it, and one point for attaching the wires.

The circuit breaker was most likely manufactured and assembled itself at a separate company. It was then fastened onto the compressor using a nut. The wires were then attached to the circuit breaker accordingly.
#4 Connect the capacitor to the plastic guard by inserting the threaded screw on capacitor into the center hole of the plastic guard. Then screw the capacitor to the crank case tab manually.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is one point for the alignment of the thread on the capacitor through the guard and one for the alignment on the crankcase.

The capacitor was most likely manufactured and assembled itself at a separate company, then being shipped to wherever the compressor was assembled. The capacitor is slid through a hole in the plastic housing. It was a threaded into the aluminum bracket to fasten it manually.
#5 Attach the wires to the capacitor using needle-nose pliers and a screwdriver.


\'\'Complexity:\'\'
The total complexity rating for this step is 5. There is a point for the pliers, one for the screwdriver, two for attaching each wire, and two for aligning each wires with the holes of the capacitor.

Small screws and nuts were used to attach wires to the tabs on the capacitor.
#6 Slide the rod onto the crank shaft through the top end of the crankcase.


\'\'Complexity:\'\'
The total complexity rating for this step is 1 for aligning the hole of the rod with the crank.

The rod was slid into the crank shaft manually with one end through the top of the crankcase.
#7 The gasket is placed on the crankcase manually.


\'\'Complexity:\'\'
The total complexity rating for this step is 4 for aligning each hole of the gasket on the crankcase.

The gasket was placed on the crankcase manually.
#8 Assemble the piston: First slide the wrist pin through the piston and connecting rod. Then insert the expansion ring in the hole using needle nose pliers.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is one point for aligning the wrist pin with the piston and rod, and one for the pliers used for the expansion ring.

The piston was held in place while the wrist pin slid through the rod and piston to hold it into place. The expansion rings were installed to keep the wrist pin from falling out, using pliers to properly secure the expansion rings.
#9 Place the small, thin plate on top of the cylinder, aligning the two small holes on the plate with the two pins on the cylinder.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is one point for aligning the plate with each of the small pins.

The thin plate was attached to enclose the piston.
#10 Attach the two U-valves to the valve seat by attaching the screws with a philip\'s head screwdriver, having the part that is bent upward on top. Then place the valve seat and gasket on top of the small plate, being sure to align the large, outer holes with the holes on the cylinder head.


\'\'Complexity:\'\'
The total complexity rating for this step is 7. There are two points for aligning each U-valve, four points for aligning the holes on the plate with the holes on the cylinder, and one for the screwdriver used to attach the U-valves.

Attach the sheet metal U-shaped part bent downward and the constrictor plate on top of the cylinder. The valve seat and gasket are aligned with the cylinder head for connection.
#11 Intake Manifold then placed on top of cylinder head, being sure to align the four outer holes. Then thread the 4 bolts through the cylinder head, cylinder, and crankcase.


\'\'Complexity:\'\'
The total complexity rating for this step is 5. There are 4 points for aligning each hole of the intake manifold and 1 for the wrench used to tighten the four bolts.

The intake manifold is bolted through the cylinder head into the crank case connecting all 3.
#12 Fit the gasket into the crankcase cover. Then fit the cover onto the crankcase being sure the holes are aligned. Then attach the 4mm allen screws using a 4mm allen wrench. Then place the oil fill plug into the hole cover.


\'\'Complexity:\'\'
The total complexity rating for this step is 8. There is one point for fitting the gasket in the cover, six points for aligning each of the holes on the cover with the case, and one for aligning the oil plug.

Placed the crank case gasket on the crank casing and installed the crank case cover. Tightened bolts down and installed the plastic oil fill plug.
#13 Pressure gauges are threaded into the pressure switch by manually turning them.


\'\'Complexity:\'\'
The total complexity rating for this step is 1. There is one point for aligning the gauges with the switch.

Pressure gauges are then threaded into the pressure switch manually by turning them.
#14 Align the pressure switch and the thread on the tank and attach the switch to the tank. Because the cord was still attached to the motor, it was required that one person hold the motor and spin around the tank so that the cord would not become twisted and tangled.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is a point for aligning the switch with the tank and one point for the extra person needed to help attach the switch.

Thread on the pressure switch to tank and then the wires were installed afterwards.
#15 Rubber feet attached to the bottom of the crank case. Then align the crank case so that the holes on the crankcase and the holes on the tank align. Bolt the crankcase to the tank with 4-12mm bolts and 4-12mm locking nuts.


\'\'Complexity:\'\'
The total complexity rating for this step is 5. There are 4 points for aligning each of the crankcase feet to the tank and one for the wrench to attach them.

Rubber feet are put at the bottom of the crank case and then bolted down to the tank for support.
#16 Attach the small copper tube by using the attached bolt and threading it onto the pressure switch and then to the tank.


\'\'Complexity:\'\'
The total complexity rating for this step is 3. There are two points for aligning each of the copper tubing ends and one for the wrench used to tighten the nuts.

Install both nuts and flange both ends and bend the copper tubing while securing one end to the tank and the other to the pressue switch.
#17 The heat exchanger/fill line was then connected from the head to the tank, again using the attached bolts and using a crescent wrench to then tighten the bolts.


\'\'Complexity:\'\'
The total complexity rating for this step is 3. There are two points for aligning each end of the tube and one point for the wrench used to tighten it.

For the heat exchanger fill line, install a nut, flange the end and install the cooling coil fins. Install the other nut and flange the end. Connect the heat exchanger from the intake manifold to the tank by threading both ends.
#18 The oil drain plug is attached to the tank using a crescent wrench.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is one point for aligning the plug and one for the wrench to tighten it.

Thread in the oil drain plug using a wrench.
#19 The safety valve was installed into the pressure switch using a 14mm wrench.


\'\'Complexity:\'\'
The total complexity rating for this step is 2. There is one point for aligning the valve and one for using a wrench to tighten it.

Thread the safety valve release plug into tank using a wrench.
#20 Zip ties were attached to bundle the wires connecting to the circuit breaker.


\'\'Complexity:\'\'
The total complexity rating for this step is 0 because this step does not relate to any of the criteria and it is a very simple step.

Zip tie the wires together so they don\'t clip the air fan as it spins and to keep the wires separate and organized.
#21 Plastic fillers placed on the side of the crankcase using philip\'s head screws and screwdriver.


\'\'Complexity:\'\'
The total complexity rating for this step is 3. There are two points for aligning each of the fillers and one point for using the screwdriver to tighten the fillers.

Screw in the plastic fillers onto the side of the crankcase to support the motor shroud.
#22 The motor shroud was placed over and attached to the crank case using a number 2 philip\'s screwdriver.


\'\'Complexity:\'\'
The total complexity rating for this step is 5. There are four points for aligning the shroud with the screw holes and one point for using the screwdriver to tighten the screws.

Snap the plastic motor shroud into the respective holes and screw on the motor shroud.
#23 The air filter was assembled by twisting the casings together with the filter inside and thread it into the cylinder head.


\'\'Complexity:\'\'
The total complexity rating for this step is 1. There is one point for aligning the thread of the air filter with the cylinder head.

Twist the two air filter casings together to fasten the air filter assembly. Thread the air filter into the cylinder head.
#24 The handle was then added to the tank attaching 2-4mm hex screws using an allen wrench, being sure that the handle is oriented so that it is bent upwards on the tank.


\'\'Complexity:\'\'
The total complexity rating for this step is 7. There are two points for aligning the handle into the two holes, four for aligning the screw holes, and one for using the allen wrench.

The handle was inserted into the two holes and four hex screws were installed to hold it in place but not threaded.
#25 The hose was then attached using the quick connect.


\'\'Complexity:\'\'
The total complexity rating for this step is 1. There was one point for aligning the hose with the pressure switch.

The hose was included in the box where the product is sold.
#26 The two rubber feet were attached by aligning the feet with the washers then the nuts and then the bolts go through the two of those and screw into the tank. The wheels were then attached by first aligning the wheels to the tank and then aligning the washers with nuts and the attaching it with the bolts. Be sure not to attach the bolts too tightly so that the wheels can still turn.


\'\'Complexity:\'\'
The total complexity rating for this feet is 4. Two for aligning each of the feet and two for using two wrenches to tighten the bolts. The total complexity rating for the wheels is 4. Two for aligning each of the wheels and two for using two wrenches to tighten the bolts.

The wheels were installed along with the rubber feet to the tank with bolts.


Design Revisions


Throughout the course of the semester and during the reassembly process, a number of ideas about design revision presented themselves. These ideas include ways to address revisions in ergonomics, performance, product safety, and economic cost/maintenance.

Initial Design


Figure 72: Kawasaki Compressor

The initial design of the Kawasaki 8 gallon air compressor combines mobility and performance in order to give clients the ability to move the compressor easily and have a stable, high performing air compressor at their work site. The design took into account the four factors: Global, Societal, Economic and Environmental.

  • Global: Common materials were incorporated into the design, the use of steel, cast iron, aluminum and various plastics were used. These materials are readily available world wide. The compressor manual also included instructions in French and Spanish. This allows for a multi-national target audience.
  • Societal: The compressor was built to be portable and provide a power source for tools, allowing the compressor to be used by contractors and individuals not associated with construction. The lighter weight allows people of varying strength the ability to move the compressor.
  • Economic: The air compressor was designed more for home use, as it is not as portable as the double stack designed air compressors. The single tank allowed it to be cheaper and be portable enough to move into a vehicle or around a work site.
  • Environmental: Most likely environmental factors were not taken into consideration, as the product was designed to be portable and able to provide a sufficient power source.

The audience targeted for this product seems to be an individual doing light work or work at home that needs to be semi portable. This targeting window limits the sales of this compressor. The compressor could be of comparable costs and performance, while also being more portable and user friendly. A few design revisions have been developed which are included below.

Double Stack Design


Figure 73: Double Stacked Tank Design [2]

The use of a double stack design would increase the portability of the air compressor without hindering performance. The double stack design is more portable for several reasons. By stacking two four gallon tanks on top of each other, there is a smaller moment in which the user would have to lift the tank in order to move it on the wheels to transport. This is turn makes it easier for the user to transport the compressor because it requires less force for the user to lift the compressor onto its wheels to move around. This design changes the storage and transport system of the air compressor on the system level, while taking into consideration the four factors.

  • Global: The change of the tank geometry does not change its ability to be used globally, and is made of similar materials that are available everywhere.
  • Societal: The design allows increased portability, which allows a greater number of people to use the products for working at home or at their place of occupation.
  • Economical: The design includes optimizing volume in respect to material, which keeps the cost of the double tank design close to the original price for a single tank because we will be using either less material or the same amount as was used for the single 8 gallon tank.
  • Environmental: The use of optimization will will allow the design to use less material which could help the environment because there would be less needed to be created, as well as the possibility of having less material needed to be recycled.

\'\'Calculations for the optimum design of each cylinder/tank:\'\'

  • 4 gallons = 924 cubic inches
  • Constraint: volume = π(r^2)h=924 cubic inches
  • Minimize: surface area = 2πrh+2π(r^2)


\'\'Solution:\'\'

  • \'\'Solve for h in the constraint:\'\' h ⋍ 924/(π(r^2))
  • \'\'Plug h into the surface area function:\'\' SA = 2πr[924/(πr^20]+2πr^2
  • \'\'Take the derivative of the surface area function:\'\' SA\'=(4πr^3-924)/r^2
  • \'\'Find critical points:\'\' The critical points are r=0 and r=4.189 inches. The radius must be greater than zero, therefore the optimized internal radius of the tank is r=4.189 inches\'\'
  • \'\'Solve for height:\'\' h=924/(π(4.189^2)) = 16.76 inches
  • \'\'Check volume:\'\' π(4.189^2)(16.76) ⋍ 924 cubic inches = 4 gallons.


From our optimization calculations, in order to have the least amount of material for a 4 gallon tank, we would need to make the internal radius of the tank 4.189 inches and the height of the tank to be 16.76 inches. The change in tank geometry do not necessarily require the need to produce a different electric motor, crank case, cooling fan, pressure switch, or pressure gauges, and the only change that would need to be made is where they are placed in relation to the compressor. These parts though would not need to be altered during manufacturing , so this revision would not change a majority of the components used in the air compressor. While the amount of material being used to make the compressor will still end up increasing because of the fact that we are using two tanks instead of one, by optimizing the size of our tanks, we can still assure to use as little extra material as possible so that the product is still affordable for the consumer.

Additional Improvement Revision

An additional improvement due to the double tank design would involve the option to change the effective tank volume. To achieve this, a ball valve would be placed in between the tanks. This valve will be able to easily be turned on and off through the use of a small lever located where the valve is placed on the compressor. This would allow the operator the option of only filling one tanks instead of both at the same time. The required pressure for one tank could be achieved much quicker than having to fill both tanks. This would be useful for short jobs in which the tank would only be needed for a short amount of time, as well as making it more convenient for the user. This also takes into account some of the four factors:

  • Societal: This feature changes the volume of the storage system, allowing the compressor to be faster to fill which makes it easier for people to use at home for smaller projects/ jobs.
  • Global: This design would incorporate a label using universal symbols, allowing users of different locations and cultures to understand how to change the tank volume.
  • Economic: The cost of the valve needed for this revision would be negligible compared to the overall cost of the compressor. The valves are readily available, and increase the usability of the compressor without significantly increasing cost would be greatly beneficial to the user.
  • Environmental: The addition of the valve allows the compressor to use less energy for smaller jobs, which prevents the user from having to fill the whole tank to full pressure for small jobs, which would waste more electricity.

Change Piston Size


Figure 74: A picture of the cylinder, marked to show how the bore would be changed.

We have also decided to make a revision to help with the overall performance of the compressor. If we were to increase the bore size of the cylinder, it would allow more air to be compressed during each revolution of the crank. The compressor\'s current motor may be powerful enough to run at a higher load, and at a reasonable efficiency, so there would be no need to change the motor to suit this new sized cylinder and piston size. The cost of this improvement would also be negligible compared to the overall cost of the compressor, therefore there would be little to no change from the targeted price point at which the compressor would be placed in. The connecting rod may need to be slightly strengthened to withstand the force from the piston, as well as increasing the size of the piston in order for it to fit correctly within the cylinder. The manufacturing processes would not change much though as there would only need to be some different sized molds for the piston, cylinder, and connecting rod. Only a couple of the four factors were taken into consideration for this design revision:

  • Societal: Increase in performance allows customers use the compressor faster because the fill rate would increase, allowing for the tank to fill faster and giving the user more time to complete jobs/ hobbies.
  • Economic: By making this change, the performance of the compressor increases while not affecting the cost much, making this compressor more appealing than other competing compressors at the same price point.
  • Global: Increasing piston size and bore size does not change how it is used and manufactured globally.
  • Environmental: This change may increase power consumption slightly, as there is a higher load on the motor.


Frame Addition


Figure 75: An example of an air compressor with a frame built around it. [1]

With the change in the tank geometry, a new frame could be manufactured to help improve user interaction with the air compressor. The frame would have several features available to the user. One example would include a place tools on the compressor. The steel frame would have another steel, table like piece with a rubber covering which would stretch across the top and front of the compressor, by connecting it with the steel tubing frame. By including this, there would then be a spot for users to place their tools while not using them. This steel piece would also include a front display to aesthetically mount the gauges and quick disconnect. By including a place for the gauges and quick disconnect to be displayed, user interaction would be more pleasing because it is easier to see the gauges as well as the the whole product becoming more aesthetically pleasing instead of just having the gauges randomly placed on the compressor. Another feature of the steel frame is that it prevents the user from becoming injured by the heat exchanging surfaces of the cylinder and motor. The frame could be built around the other components, allowing components of the previous design to be used, while also protecting the user from some of the possibly harmful components of the compressor. Steel tubing is easy to manipulate into shape and is a relatively low cost material to work with, so it would therefore be fairly cheap to implement onto the compressor. This revision also took some of the four factors into consideration.

  • Societal: The addition of a frame will allow the compressor to be picked up easier, by a larger range of people. The table would make the compressor more aesthetically pleasing as well as being more user friendly. It will also prevent burn injuries to the operators.
  • Economic: Steel tubing was chose as a strong material was needed. At less than 3 dollars per foot, steel tubing is an economical choice.
  • Global: The addition of a frame around the compressor will not change how it is manufactured globally or used by people of different cultures and geographic location.
  • Environmental: Environmental considerations were not taken into account during this design revision.



\'\'References\'\'


[1]EveryAirCompressor.com. Web. 9 Dec 2010. <http://www.everyaircompressor.com/Grip-Rite-GR2540-GRT1021.html>.

[2]Buzzillions.com. Web. 9 Dec 2010. <http://images.buzzillions.com/images_products/05/90/2629741_raw.jpg>.