Group 5 - Kawasaki Compressor 2 Gate 4
Contents |
Project Management: Coordination Review
Cause for Corrective Action
The project plan has worked fairly well thus far, but this does not mean that it has been perfect. Part of the problem has been that the plan itself was somewhat vague initially, forcing us to readjust our sub-plans and priorities from time to time. To be fair, it was difficult to outline a very specific plan from the beginning of year without necessarily having an appreciation for what each step would entail. This makes it difficult to define how the plan has necessarily ‘failed,’ since its vague quality ensures that most of the time, it succeeds (which we realize is a bit of a caveat).
A specific example of how the plan has failed (illustrating the point above about not having a real appreciation for each step entails at the beginning of the year) is in regard to the design revisions section of the previous gate submission. Initially, we did not anticipate the design revisions section of the previous gate to take very much time. However, when it came time to complete Gate 3, we realized that since design revisions needed to be made cognizant of the four design factors (global, societal, environmental, and economic) and other considerations, this step required more time and consideration than we otherwise originally thought.
To illustrate how changes have been made to our plans (or need to be made), we examine certain resolved and unresolved challenges. An example of a resolved challenge concerns defining meeting times. It should be noted that in Gate 1, we had defined generally what time of day would be best for meeting (after 5 PM), which has always been agreed upon by all group members. The challenge stemmed from having to define a specific time to meet each week (e.g. 8 PM). This would usually be resolved by email, where the project manager would survey group opinion for the best meeting time (e.g. Wednesday at 7 PM or Thursday at 8 PM). At one point, a meeting time was defined in a previous email, but since it was not finally confirmed by the project manager in a separate email, some group members did not show up to the meeting, despite indicating that they were willing to meet at that time which all other group members agreed upon. This was a misunderstanding which has been ameliorated by defining meeting times farther in advance, along with the project manager sending a final confirmation notice of the meeting time.
A final unresolved challenge which needs to be addressed regards the personal initiative of group members to meet internal deadlines. Essentially, one of our biggest flaws as a group has been that despite defining sub-deadlines in advance of final gate submissions, they have not been frequently met. The only real solution that we can find to this problem is to define even earlier sub-deadlines so that even if they are missed, they may still be completed ahead of when the final gate submission is actually due. This time, we set a goal of completing all parts of this gate 3 days in advance of the final due date, which helped to a certain degree. This gave us more time to do more background research into our respective parts (since with the extra time, we often realized that our original ideas could be improved).
Product Archeology: Product Explanation
Product Reassembly
Having been through the disassembly process, the reassembly of the compressor seemed relatively straight forward. Though it was simpler in that we knew what needed to be done, reassembly and documentation actually consumed more time, about three and a half hours. With reassembly came different complications than were present in disassembly. This necessitated the development of a new difficulty rating scheme. Instead of time being the sole determiner of difficulty, a sliding scale ranging from a minimum of 1 to a maximum of 5 and being dependent upon three variables was devised. The values are determined by evaluating the amount of time consumed, the number of components involved in each step, and the number of operations needed to set the components in place. This system was devised so that no one factor of reassembly could mischaracterize the level of difficulty of a step. Here is an example of the system in use. The reattachment of the air filter assembly is a perfect one. It involves manually aligning and rotating a single entity into place. It takes less than five minutes.
Difficulty Rating Explanation:
1- Entails aligning and executing a function on one to two components in a minimal time span.
2- Only exceeds the minimum by a reasonable increase in no more than two of the factors. (ex. Like a step involving multiple iterations of tasks that would independently be deemed 1's)
3- This step exemplifies the average level of complexity and required effort of the steps in the reassembly process.
4- A step of this rating exceeds a 3 in having no more than two of the variables incapable of being called average. It is taxing but not insurmountable.
5- A step of this difficulty dominates the three and one half hour reassembly time and involves a high number of complex operations that is only rivaled by the number of components involved.
| Picture | Steps | Difficulty Rating |
|---|---|---|
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Step One (Secure Wheels and Rubber Supports to Tank): First, the tank was rotated ninety degrees onto its side so that the rubber supports could be added. The stoppers were secured by aligning the bolt through the rubber supports and continuing through the stabilizing bar that is welded to the tank. A washer was added before the nut was screwed on using a 14 mm wrench. The wheels also were secured by aligning the bolt through the wheel and continuing through the bracket that is welded onto the tank. A washer was added before the nut was screwed on using an 18 mm socket wrench. These parts were most likely originally assembled by a human worker. The reason being is the space limited for a robot to complete the task. |
-(3)While individual assessment of replacement of any one of the four sets of components would have resulted in a 1 rating, the combined level of difficulty in the management of the components and the increase in time spent performing tedious operations increased overall difficulty to a 3. |
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Step Two (Placing Piston with Piston Housing): First, the gasket, plate, and valves were manually replaced between the piston cylinder and the intake/discharge manifold. The piston was then placed into the cylinder by compressing the three o-rings by hand and being forced into the cylinder while being level. The piston and housing were originally assembled by a robot because all of the o-rings need to be compressed for the piston to function. During reassembly, this step took longer than expected because of its tedious manner. This was hard for one person to individually compress the three o-rings while pushing the piston into the cylinder simultaneously. |
-(3)Though the pieces fit together with puzzle piece precision, time and effort was mainly consumed in trying to fit the piston back into the cylinder by manually compressing the o-rings, as we did not have tools for this specific purpose. |
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Step Three (Piston Reattachment to Crankshaft): After the piston was in the cylinder, the connecting rod of the piston was aligned and secured to the crankshaft. Once again, this step was performed by hand. This step of assembling the connecting rod to the crankshaft was most likely done by hand because it is a simple operation. The worker would only need to slide the connecting onto the crankshaft; there is no lock or pin to secure the rod to the crankshaft. |
-(2)Here only two components were immediately involved, however it took time and tricky maneuvering to set the connecting rod in place on the piston. |
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Step Four (Fastening Piston Housing to Crankcase): The piston housing, with the piston and intake/discharge manifold in correct orientation, was aligned and set atop the crankcase. The four bolts were then fed through the manifold, gasket, and cylinder into the crankcase and tightened with a 12 mm socket wrench. The attachment of the piston housing to the crankcase was done by robotically because it has to be secured to ensure all the valves have a proper seal. |
-(2)This is an example of the combination of four level 1 operations amounting to a 2. |
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Step Five (Reattachment of Crankcase Cover): The crankcase cover and rubber lubricant seal were fastened to the crankcase using a 5/32 in Allen wrench to tighten the six screws. The plastic lubricant inlet stopper was then put in its place at the top of the crankcase cover. The completion of the crankcase assembly by adding the cover and gasket was done by a robot because of the need for the gasket to be air tight. Also, hex nuts were used to screw together the cover to the case. Using these hex nuts would allow a robot to work at various angles, where different screws would not give that option. |
-(2)Though a relatively quick step, number of components involved and complexity in the management of the gasket during reattachment warrant a rating of 2. |
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Step Six (Reconnected Stator cover and stator to crankcase): A rubber mallet was used to secure motor cover to stator. Then a 7mm wrench was used to tighten four bolts and a fix the motor to the crankcase. The connection of the stator cover to the stator was done mechanically because of the force needed to fasten the two together. A robot also put the stator into the crankcase for the same reasons. Although a human worker would connecting all the wires in the stator to the capacitor and circuit breaker. |
-(4)This took more time than was expected. Alignment was more difficult as some parts originally imposed pressure on other parts. In reassembly that pressure became present again. |
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Step Seven (Capacitor): Screw capacitor through plastic mount into the crankcase manually and secure in place by tightening nut with 14mm wrench. Then, using a Philips head screwdriver reconnect electrical wires from the motor to the capacitor. The capacitor was probably assembled by a human because it was loosely assembled, an easy piece, and the wires were manually connected. However this part was created by a human, it was only assembled to the air compressor by one. |
-(2)This step was straight forward but was complicated by the clearance between the nut that needed tightened and other parts of the product that impeded our efforts. |
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Step Eight (Circuit Breaker): Manually replaced circuit breaker as well as completing the electrical connections between the circuit breaker and the motor. The circuit breaker was also assembled by a human because of the ease of the task and the wires were also manually connected. However this part was created by a human, it was only assembled to the air compressor by one. |
-(2)The component was put in place relatively easily, but manually adjusting the nut that secured it because of clearance issues proved difficult. |
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Step Nine (Gauges): First, a nut was manually screwed onto threaded valve exit. Then the gauge unit was manually screwed onto the threaded valve following the nut. The gauges were robotic attached because of the seals. This meaning that the gauges cannot leak air while taking readings. |
-(2)This step was executed twice as it was determined that the nut needed to be overtightened to ensure that the gauge assembly was stable. |
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Step Ten (Attachment of Parts to Tank): The previously assembled parts excluding the gauges were lifted onto the top of the tank and the four bolt holes were aligned with the brackets on the tank. Four bolts and nuts were then tightened using a 12mm and a 13mm wrench. This step was done by a robot because this compilation of parts to be in securely in place. The vibrations from the piston will shake the entire unit, but these parts still need to function and being tightly in place will secure their place. |
-(3)Though it seems easy in theory, it took three people. One person held the components, one held the bolt, and one tightened the nut. Given small clearances, tightening the nut was a lengthy process. |
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Step Eleven (Attachment of Hoses and Lines): Manually reconnect the compressed air discharge line between the intake/discharge manifold and the tank. Also reconnect the hose that delivers the compressed air for use to the gauge apparatus. The hoses and lines were assembled by a human because of the simplicity and easy nature of the task. |
-(2)Two of the air transport lines were rigid and gave some resistance to attempts at alignment and reattachment. |
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Step Twelve (Handle Bar): Manually reattach the handlebars to the bracket on the top of the tank. The handle bar was assembled by a human worker as well because the bar needs to be placed in at a certain angle that would be difficult for a robot to accomplish. |
-(1)This step was extremely simplistic only requiring alignment and tightening of few parts. |
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Step Thirteen (Attach Fan to Motor): Fan was manually attached to the back of the motor and secured using a small metal clip as well as a hex nut that was tighten using a 5mm Allen key. This task was performed robotically because it was most likely done right after the stator cover was attached to the stator. This would be the most logically sequence of events. |
-(1)Again a step that was as brief as it was simplistic. |
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Step Fourteen (Replacement of Cover and Air Filter): Replace plastic fan cover by using a flathead screwdriver to tighten the four screws. The air filter was then manually screwed threw the plastic cover into the threads located on the top of the piston housing. The cover of the air filter was put on by human workers because it needs to be manipulated to fit over everything. The air filter was than manually screwed afterwards because it is a matter of being put through the cover to the piston housing. |
-(2)Part of this step was used as an example above. that step plus one of equal difficulty resulted in us rating it a 2. |
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Step Fifteen (Reassembly of Regulator): First we placed two springs inside the plastic mold in the two appropriate locations. Then the black plastic piece was reinserted into its vertical slot. Below this plastic piece a metal connecting plate was tightened in between the plastic and an additional metal cover. The small metal handle was then inserted through the side of the casing and placed under the metal plate. This allows for the handle to turn the regulator from automatic to off. Next, the unit was mounted onto a bracket from the gauge assembly using four Philips head screws. Lastly, a plastic covering was placed over the unit and secured with one spanner drilled tamper proof. The regulator was created and assembled by a robot because of the complexity of its function and where it is placed on the air compressor. |
-(5)This was by far the most difficult step. It took multiple attempts to accomplish. Aside from consuming much time and involving many small components, it tested both mental ability and fine motor skills. |
Assembly vs. Disassembly
Conceptually, assembly and disassembly differ in that one constructively yields a whole that is greater than the sum of the parts within it and the other aims to reduce that whole to its component parts using any necessary means. Ideally they are opposites, reverse operations of each other. This, of course, is not the exact case. Often a different tool set is required to meet the needs specific to either situation, as was the case for us. Disassembly, specifically, risked some minor destruction to part integrity in the name of reducing the product to its component parts. This was partly due to both the use of excessive force needed to achieve disassembly and a lack of initial internal knowledge about the compressor. The concerns behind assembly are much more thoughtful. The aim is to return the product to a state that is as close to the condition in which we received it as is possible. If there were a part that exemplified the differences between assembly and disassembly, it would be the regulator. It came to us as an enigmatic black box. Needle-nose pliers had to be used to loosen the screw holding the cover on because of clearance issues. When the cover was taken off, parts immediately changed orientation. Springs that had been compressed pushed their way straight and plates that had been suspended in place fell to either side. We had essentially opened a new puzzle. When it came time for reassembly, a new approach to the regulator had to be devised. Once the internal structure was forensically derived, parts were fixed in place by hand in a delicate and lengthy process. A Torx screwdriver was used to then fasten the four internal screws that before were removed either with a flat-head or by hand. Finally, the cover was replaced and fixed in position. In short, assembly can possibly be a mirror held to disassembly operations, but it will more likely be two adjacent worlds where each product presents unique problems to either.
Design Revisions
For a second set of design revisions, changes that affect the problem at a system level are proposed. Once again, attention is given to how the proposed changes would address the four fundamental design factors (global, societal, economic, and environmental) in the context of how they apply to the given target audience, which has been determined to be made primarily of private consumers and perhaps some small businesses (refer to the Design Revisions section of the previous gate for further detail).
Air Compressor Mobility: Dolly Setup
The first suggested design revision concerns the physical mobility of the compressor. As many consumers will purchase this product for personal use, it is important that the compressor be fairly portable. Unlike larger air compressors employed in shops and industry that are typically fixed in place and are generally not meant to be moved around, this air compressor needs to be easy to transport around the house, or wherever else the consumer would need it for personal use. This design consideration of mobility addresses the performance and reliability of the compressor, which can be generalized as societal and economic concerns. As the relative ease of mobility of the compressor increases, its perceived reliability as a product increases as well (since the compressor could be applied to a wider range of projects and applications). Ease of mobility also addresses an ease-of-use factor, as creating a product that is hard to transport implies greater difficulty of use. Reliability and ease-of-use are both societal values which American (or more generally, North American) consumers place on and come to expect from their products, and thus this addresses basic societal concerns.† The way economic concerns are addressed goes back to the point about how a more mobile compressor implicitly has a wider range of applications and uses. If the compressor proves difficult to transport, then one would have to purchase other products to complete more specific tasks (i.e. nailing on a house rooftop) that perhaps a more mobile compressor would have been able to handle without much hassle. As such, increased mobility helps the versatility of the product, helping the consumer save money by purchasing one well-rounded appliance instead of several ones that collectively perform the same jobs.
Having discussed how the mobility of the compressor addresses some of the four design factors (and the target audience), it is a good time to examine the specific strengths and weaknesses of the current design, and how it can be improved with this group’s suggested revisions. Refer to Figure 1. Currently, the Kawasaki Air Compressor rests on two large plastic wheels on one end of the tank, and two rubber supports on the other end of the tank. On the side where the two rubber supports are, the handlebar rests on top of the tank, and is angled upward, allowing for the user to grab the bar from a higher vertical height. This is known colloquially as a ‘wheelbarrow’ setup. The advantage of the wheelbarrow setup is that, since the compressor is resting on wheels on one end, the user does not have to physically lift the entire compressor with hands and arms (which even when empty has significant weight), and the user has decent control over turning the compressor left and right when ‘driving’ it, so to speak. The disadvantage is that, although the consumer has less lifting to do when transporting the compressor, he or she still has a vertical load to support. Moreover, one needs to bend over in order to grab the handlebars, forcing one to lift the compressor with his or her back. These weaknesses demonstrate a failure to adequately address the societal concern of the safety and health of the consumer, forcing the user to bend over to support a compressor that is not exactly light.
To address these weaknesses, it is suggested that the manufacturer reconfigure the compressor so that it resembles a ‘dolly’ setup. Refer to Figure 2, which displays an existing air compressor on the market by a competitor that exhibits this design. To make the comparison fair, a compressor that has very similar performance characteristics was chosen to demonstrate this alternative design (i.e. 3.5 HP, electric, 8 gallon capacity compressor). Like a dolly, this setup has a base and handlebars that extend from the base upward in the vertical axis. The motor-piston housing-crankcase assembly on top of the Kawasaki air compressor is kept intact and placed on the base of the dolly in this setup. Also on the base is one of two storage tanks (here the 8 gallon total capacity is split into two tanks, a feature that this group values and is the subject the second system level design revision). One can place the second detachable tank on top of this base to take advantage of the full 8 gallon capacity of the compressor. The only other major rearrangement of parts is the regulator, which, instead of resting on top of the air storage tank like on the Kawasaki air compressor, rests on one of the structural bars on top of the motor-piston housing-crankcase assembly.
This dolly setup yields numerous advantages. First and foremost, it makes transporting the compressor much easier. Unlike with the Kawasaki air compressor, one would not have to bend over and lift to transport the compressor. The handlebars in the design revision should be accessible to the tallest of consumers. A solution for taller consumers is to install handlebars that have steady, securable, reconfigurable heights so that any person of any height can move the compressor without stressing one’s back. A dolly by nature is meant to help transport heavy items without requiring lifting or much effort at all besides the initial effort required to tip the dolly into mobile mode. It should be noted that the weight of this configuration is concentrated near the base (i.e. the motor-piston housing-crankcase assembly and the permanent un-detachable tank), giving the consumer a larger lever arm when pushing down on the handlebars to tip the dolly to begin transporting it. By increasing the ease of mobility, this setup addresses the societal concern of the health and safety of the consumer, in addition to the other societal and economic concerns addressed in the first paragraph of this section (i.e. the societal and economic implications of an easier to use, more versatile product, among other things).
† Note that because of the power input rating for the electric motor and the plug to the compressor, the product is intended for North American markets. For further explanation, refer to Gate 1.
Air Compressor Mobility: Second Detachable Air Storage Tank
When analyzing the Kawasaki Air Compressor, it is clear that the compressor is incapable of producing compressed air when a source of electricity is not available. This could potentially pose a problem for a user who wants to be able to use the product at a remote location such as a log cabin, where the only source of electricity is likely a generator. For the sake of making the compressor more versatile, some changes could be made to the design in order to allow the product to still perform its function in situations such as this, without having to rely on expensive products such as a generator. By addressing the versatility of the product, the economic and societal design factors of the compressor are being considered. As mentioned in the first design revision, the versatility of a product is a societal value that has developed among American consumers. In the example of an air compressor, it is likely that consumers will expect the product that they purchase to address all of their needs for compressed air production, not just some of them. Since making the air compressor more versatile has the potential to allow a consumer to complete more tasks without having to purchase additional products (generator, inverter, power extension cords, etc.) it also creates a great possibility for saving the consumer money, hence the reason why improving versatility involves economic factor consideration.
There are a few of ways that the compressor’s design could be revised in order to accomplish the objective of allowing it to be functional in an environment that lacks an electricity source. First, consider adding a rechargeable battery to the compressor. While this may seem to be a logical solution, a closer look at the design factors indicates otherwise. Because of the high energy demand from the three-horsepower electric engine, a large battery would be necessary to power the compressor, even for a short period of time, especially due to the fact that the compressor’s start-up load is significantly higher than its continuous load. In order to incorporate a battery of this size, the economic, societal, and environmental design factors of this product would all be impacted. In terms of the economic design factors, batteries of this size are expensive and would cause the compressor to move to another price point, making it no longer directly competitive with others that have a similar capacity and motor power. In addition, the size of the battery would create a large increase in the overall weight of the compressor, making it even more difficult to transport, and likely requiring some revisions to the mobility subsystem (the wheelbarrow or dolly setup). The decrease in mobility detrimentally affects societal factors (see the first design revision for details), and the required revisions to the design could potentially result in a higher cost as well. Finally, the inclusion of a battery incorporates a negative environmental affect since they cannot be recycled, decompose extremely slowly, and contain harmful acids.
Next, consider adding a DC to AC inverter to the compressor. This poses many of the same negative design factor effects as the battery, especially in driving up the cost (economic) and increasing the weight, thereby decreasing the ease of mobility (societal). While this would be useful to the consumer by allowing them to power the compressor via their car or truck by plugging the inverter into their car battery connection inside their vehicle, the cost of an inverter that would be capable of supplying the sufficient amount of power to the compressor would be extremely high, and would probably double the overall cost of the product. What makes this revision even more impractical is that it would be more useful for the user to just buy an inverter separately, so that they can use it with other products in addition to the compressor. In retrospect, unless a method of easily switching the engine’s wiring between the current energy input subsystem (AC outlet setup) and the hypothetical battery setup directly was established, an inverter would have to be incorporated as well; further proving why including a battery is not a viable solution.
Since the addition of a battery or inverter has been proven to not be a logical solution to the problem of allowing the compressor to serve its function in an environment without an electricity source, another system level design revision that would be quite advantageous to the Kawasaki Air Compressor should be considered. This revision is the addition of a second air storage tank that is detachable and, therefore, portable. A change such as this extensively increases the versatility of the air compressor for a number of reasons. First and foremost, the consumer now has the ability to produce compressed air and then utilize it wherever necessary without bringing the compressor itself along. As goes without saying, this supply is limited, but in cases where the amount of compressed air needed is smaller, or the compressor cannot be utilized due to lack of a source of electricity, this ability becomes extremely useful. Also, the detachable tank on its own would be much lighter than the compressor in its entirety due to the fact that a large portion of the weight is from the engine and crankshaft. In contrast to the proposed solutions of adding a battery or inverter, the incorporation of a second detachable tank actually has the potential to decrease the amount of weight that a user would have to transport to utilize the compressed air. This revision has positive impacts on the compressor’s economic design factors as well. The second tank allows for the compressor’s overall capacity for compressed air to be increased marginally without significantly increasing the size, weight, or price of the compressor. For example, two horizontal five-gallon tanks mounted vertically on top of one another would only cause a slight increase in the weight and amount of occupied space from a single eight-gallon tank. This increase in storage proposes benefits by means of the compressor’s engine operating in time intervals that are spaced further from one another, which, depending on the rate at which the air is being used, has a potential to cut-down on noise pollution, a societal concern. The larger storage volume would cause a small increase in the amount of time it takes the compressor to fill its tanks, but since the engine’s running power load is substantially less than its start-up load, this revision would actually help to cut down on energy use (a global design factor), which throughout the lifetime of the product, will save the user a notable amount of money. One might argue that the net increase in tank size and the division of the compressed air into two tanks would cause an increase in the users initial investment, which would be true; however, tanks are fairly cheap to manufacture, and the steel alloy of which they are composed is cheap as well, so the compressor price point would be similar, and the numerous benefits that the second, detachable tank poses should more than compensate. In fact, the money that is saved by cutting-down energy usage will more than make up for this increase in initial cost.
As already stated, an increase in the versatility of the product addresses the societal design factor of consumers expecting the products that they purchase to fulfill as many of their needs as possible. The second, detachable tank helps to optimize said versatility.
Piston Setup Revision
(Note: Due to the nature of this design revision, the group feels it is more appropriate to put in this particular gate, since it is concerned with system level changes. This alteration is fairly significant and has several macro-level effects which fit better here than with other component level design revisions. In its formal place in the third gate, the group shall place a forthcoming design revision regarding one of the handles on the air compressor tank, which shall be available with the final project submission. These changes were made with the permission of the instructor.)
The final system design revision considers changing the compressor's current piston setup, which shares the same setup as a typical automobile engine (with a piston that is attached via a wrist pin to the connecting rod, which slips onto the crankshaft) to a setup that uses a one-piece piston/connecting rod. This latter option is described generally as a ‘fixed piston oil-less compressor.’ An article from Popular Mechanics best describes this setup, stating “…Because there is no wrist pin, the piston leans from side to side as [an] eccentric journal on the shaft moves it up and down. A seal around the piston maintains contact with the cylinder walls and prevents air leakage.” [2] Refer to the Figure 3, originally from Popular Mechanics, for a visual representation of this setup relative to the current one.
One may ask what possible advantages the ‘fixed-piston oilless compressor’ has over the ‘automotive-type oil-lube compressor’ that the Kawasaki Air Compressor currently possesses. The key is in the name of the latter option: the fixed-piston system is oil-less.
Having an oil-less air compressor addresses performance concerns which can be generalized as societal and economic concerns. In the automotive-type piston setup, oil splashes through the system, entering the cylinder, ensuring that the piston and cylinder are properly lubricated during operation to help provide for greater operating efficiencies and to allow for the proper maintenance of these parts and others. The oil ring is intended to keep this oil splashing process separate from the air compression process and ultimately the air that it is output by the compressor. Nevertheless, through continued operation, some oil will enter the air transport subsystem (refer to Gate 2 for subsystems descriptions) and will ultimately become saturated in the pressurized air output. In some industrial applications, having some oil in the air output can be tolerated, however for home and small business applications (for which this compressor was designed), having oil in the air output is not a good thing. For instance, one popular use of an air compressor for personal use is to attach it to a paint spray gun that allows the paint to become aerosol, making paint jobs quicker (also a popular application for small businesses). In this example, keeping oil that lubricates the machine separate from paint addresses basic economic concerns of performance. Paint aerosol with oil mixed into it would not be very effective, and more likely than not, one would require more paint and a second paint job to complete the same task that may have been completed in a shorter time period with less expensive paint if oil had not originally compromised the aerosol.
Keeping oil independent from the air output also addresses basic societal concerns of safety and health. Operating an air compressor that puts out air with oil mixed into it would not be safe to breathe in, and as the personal use of a compressor is typically much more casual than any industrial use (industry is required by law to provide workers with safe working environments, which includes proper safety gear for operating machines), it is possible that over the long-term, this could pose a health risk to those who operate a compressor. It is also important to note that a home environment includes children and is not made up of only fully-matured adults (unlike an industrial environment), and if an active air compressor helps distribute oil-permeated air, this could pose an even greater health risk to children whose respiratory systems are still developing. These societal concerns of health can quickly turn into economic concerns due to the potential liabilities of future litigation of these who may claim adverse health effects from operating a compressor that outputs oil saturated air.
Still, the most significant improvement from having an oil-less piston setup is the fact that it would require less regular maintenance, which is a special strength for a product that is intended for personal use. The societal concern of not having to worry about maintaining another appliance is especially important to consumers. In the current setup, one needs to be prudent about making sure the compressor has a proper amount of oil at all times, lest the piston and affiliated components wear out very quickly, leading to an nonfunctional air compressor. By switching to a fixed-piston setup, one does not have to worry about regularly checking oil levels, making the product more attractive to the potential buyer. The drawback is that in the long-run, the fixed-piston setup may require more serious one-time maintenance costs than the current setup precisely due to the fact that it is oil-less. This may appear to be a caveat that is designed to catch the naïve consumer (that not having to perform regular maintenance on an oil-less system means more significant one-time maintenance costs down the road), however it is important to note that the initial cost and maintenance costs of the compressor do not make the majority of its lifetime cost as a product. The reality is most of the lifetime expense of an air compressor goes towards the cost of the energy. Industry experts estimate that energy costs alone can account for 70% - 90% of the total cost of ownership over a ten year span (a typical lifetime for an air compressor). The initial cost and cost of maintenance accounts for the other 10-30%. Putting in this into perspective, variations in maintenance costs would, on a relative basis, not be that heavy of a burden on the consumer. As such, it may be more prudent for install a fixed-piston oil-less system that requires less regular maintenance from the consumer. Another advantage of this system is that it typically has a lower initial cost than that of the current system, and so this could compensate for greater one-time maintenance costs in the future. [1]
References
[1]- "Air Compressor Buyer's Guide: Everything You Need to Know ." 360MachineTools. N.p., 2010. Web. 17 Nov 2010. <http://www.360machinetools.com/air-compressor-buyers-guide.htm>.
[2]- Klenck, Thomas. "How it Works: Air Compressor." Popular Mechanics. Hearst Communication, 01 May 1997. Web. 17 Nov 2010. <http://www.popularmechanics.com/home/improvement/energy-efficient/1275131>.
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