Gate 2 - Group 4
Gate 2: Product Dissection
In Gate 1 we organzied our group, researched our product (the DeWALT DW511 Hammerdrill), and set the groundwork for the next step of our analysis; the dissection. Bringing us to Gate 2, we now begin the dissection process, where we follow our plan to take apart the product and learn more about its functionality and design. Displayed below in this gate, you will find a clear and easy-to-read, step-by-step process of how we completed this task. By providing a clear description, tools used, and images for each step, we ensure that any reader will be able to dissect this part following our directions. Following our disassembling process, we also documented the knowledge we acquired throughout this stage of our project, answering questions about ease of disassembly and the functionality/arrangement of subsystems.
Project Management: Preliminary Project Review
In Gate 1 we established a management system and work proposal for this project, along with known challenges faced, and possible future challenges we expected to come across. We were correct with reguards to some aspects, but quite off with reguards to others. Below, we provided a quick assessment of these different factors, and how our expectations were or were not reached.
Organization of Disassembly
- Our organized plan for disassembly was beneficial. By taking our time and documenting each step of the procedure, we were able to create a clear set of step-by-step directions. In Gate 1 we said "Each part removed will be bagged and numbered. All parts will be recorded with their corresponding number and the parts function". We did exactly that, along with taking pictures for each step. Once the disassembly was completed, we were able to align the indivual parts for a clear exploded view.
- We made the estimations that disassmbly would require Philips and flathead screwdrivers, an allen wrench, and a knife; all of which were incorrect. Tool requirements ended up only being (other than the use of our hands) three Torx screwdrivers: the t-10, t-15, and t-20.
Required Time For Dissection
- Guessing it would take us 2 hours to complete the dissection, we overestimated by an hour. It took us just under 60 minutes to seperate the drill into all of its components, and that includes time for documentation of each step. If there was a rushed need for its disassembly, we expect the procedure could be accomplished in under a half hour.
Group Meeting Times
- This factor of the project has proved to provide the most challenges to our group thus far. We set original meeting times as a rough estimate for Mondays and Fridays before class, but some members have other classes, preventing them from making it. All four members live locally at home, and have very limited availability due to other homework, and mostly, work. Since the start of this project we have only successfully met one time where the group was in its entirety (excluding directly before or after class). We have worked hard to overcome this challenge, but it is inevitable. Our only solution has been to meet in separate sub-groups on occasion, and then discuss our accomplishments via texting, internet, and in class.
- We stated that some of our group capabilities included being "mechanically inclined" and there was some prior electrical experience. This held true and was benficial during the disassembly because it made the procedure easier, and allowed us to understand the functionality of the part, and exactly how the individual components inside interact with one another.
- Prior to this project not a single member had any Wiki-documenting experience or knowledge. As a solution, we have all spent considerable amounts of time researching and learning how to use this program.
- We have limited electrical component knowledge, which we feared would hinder our understanding of the complete functionality of the hammerdrill. However, we collectively were able to understand and figure out the purpose of each part and how it worked.
- The closest thing to technical communication any group member has, is from lab reports written for other classes. This project is helping develop our skills in this area.
- In Gate 1 we stated that "the group does not believe there will be any challenges faced during the disassembly and reassembly of this product". Although this held true for the disassembly, it does not necessarily hold true for the reassembly. During the disassembly, we had to disconnect some wires connected to the motor. Since we aren't very experienced in assembling electronics, this will provide a challenge to the group when it comes time for reassembly. If we find it imperative to reconnect the wires for future product use, we will execute the option of having an experienced electrician aid this part of the reassembly.
Product Archaeology: Product Dissection
- The DeWalt DW511 Hammerdrill was relatively easy to dissect, taking under an hour to take apart while documenting each step along the way. In order to define a difficultly scale for each of the steps in our dissection, we decided to rank the level of difficulty from 1 to 4, 1 being the easiest and 4 being the hardest (difficulty scale is defined below, just before the dissection steps table). The scale we defined takes into account the amount of time, tools, and thought process required to complete each step. Overall the whole dissection process was quite easy to complete besides the dissection of the chuck which we were unable to do due to complications with the product. The chuck may be intended to be dissected, we were unable to do so because of the age and major wear on the drill.
|Difficulty Level:||Required tools and time:|
|1||No tools, takes a few seconds, doesn't require knowledge of mechanical systems.|
|2||No tools, takes a minute or more, requires knowledge of mechanical systems.|
|3||Requires a tool, takes a few seconds, doesn't require knowledge of mechanical systems.|
|4||Requires a tool, takes a minute or more, requires knowledge of mechanical systems.|
Shown below is the step-by-step process we took to disassemble our product.
|Step #||Descriptive Action||Tool Used (If Any)||Difficulty||Image Guide|
|1||Remove detachable support side handle from tool, by twisting handle in a counter-clockwise motion to loosen its grip.||none||1|
|2||Continue twisting the handle until it completely unscrews and seperates from the lag bolt/clamp.||none||1|
|3||Remove the 1/2" x 4" lag bolt from the circular clamp by simply sliding it out.||none||1|
|4||Remove three (3) screws from back of drill handle.||Torx t-15 screwdriver||3|
|5||Remove the rear casing from the back of the handle.||none||1|
|6||Remove front two (2) screws from the top of the gearbox casing. (front end of drill)||Torx t-15 screwdriver||3|
|7||Remove front screw from the bottom of the gearbox casing. (front end of drill)||Torx t-15 screwdriver||3|
|8||Slide the chuck* assembly and gearbox casing off from the front end, revealing the gearbox assembly.||none||2|
|9||Remove the gasket ("o-ring") from the gearbox assembly.||none||1|
|10||Remove relatively short-lengthed shaft (has two gears located on it) from the gearbox assembly.||none||1|
|11||Remove the single ball-bearing from the rear end of the shaft removed in the previous step. (step 10)||none||1|
|12||Slide the Hammer/Drill operation selector switch out from the top of the drill.||none||1|
|13||Remove two (2) screws from the rear end motor.||Torx t-10 screwdriver||4|
|14||Remove two (2) outside parts of the motor assembly.||none||2|
|15||Slide the trigger assembly/electrical power cord out from the handle casing.||none||1|
|16||Remove the positive (+) and negative (-) wires for the motor.||none||2|
|17||Remove the positive (+) and negative (-) wires for rear motor power terminals. (reverse)||none||2|
|18||Remove the trigger assembly/ electrical power cord from the entire assembly.||none||1|
|19||Slide the motor shaft out from the motor assembly.||none||2|
|20||Remove the black plastic collar from the frontside of the motor housing.||none||2|
|21||Remove the two (2) coarse-thread screws from the inside of the motor housing.||Torx t-10 screwdriver||3|
|22||Remove the outside of the motor from the casing.||none||2|
Difficulties in Dissection
- The chuck assembly is an inseparable part of the drill. Our group has tried everything from heating the barrel, to using an impact wrench with a torx bit and even simply using a torx screwdriver to try and loosen the torx screw located in the barrel of the chuck. The years of use this drill has been put through has actually helped tighten the screw through vibrations and by the counter thread of the screw itself. Two T20 screwdrivers were ruined trying to loosen this screw.
Parts not intended to be disassembled
- The trigger assembly would me quite difficult to take apart. It includes many small parts that just snap together. If taken apart, it would be extremely difficult to put them back together correctly.
Trigger assembly with power cord
- Trigger assembly is connected to the power cord with copper wire. If you disconnected these two parts, you would have to solder them back together.
- The parts on the motor shaft are welded and soldered together. To take it apart would take a lot of force. Also it would be impossible for the group to weld parts back together.
- The motor is very small. The parts are not meant to be taken apart. If taken apart, it would be extremely difficult to put back together.
Gears on shaft
- The gears are force fit onto the shaft. Therefore the gears are impossible to be removed from the shaft.
- As stated above, the chuck assembly was inseparable due to the condition of the drill. Two tools were ruined in the process of trying to take it apart.
Product Dissection Assessment
The internal components in the system are connected in a way which allows for the device to function properly as designed. There are multiple subsystems required which if absent, the drill would cease to perform as intended.
Arrangement of subsystems
The overall subsystem connections are arranged in a way in order to function properly and allow for the hammerdrill to work as intended with ease. The power cord is connected to the trigger assembly which connects to the motor forming a bond to the gearbox assembly and the chuck. They are all connected in a series arrangement and will only work in the order described. If any of the systems are reversed or are not in an adjacent series arrangement, the hammerdrill will no longer function. Due to the wiring on the back end of the motor and trigger assembly, the chuck and gearbox can not be in the adjacent vicinity due to their moving parts. The design incorporates a sufficient amount of space between each subsystem in order for wires and the like to not interfere with moving parts thus causing a product failure. The overall product is setup in a way for each subsystem to work correctly and not interfere with subsequent subsystems in either direction.
Power cord connection to the trigger assembly
- Physical connection: The power cord plug is connected to the trigger assembly by wiring. Two (black and white) wires extend from the plug connecting to the positive and negative terminals on the trigger assembly.
- Energy connection: When connected to an outlet, the power cord supplies an electrical energy flow to the trigger assembly through the wires housed to the trigger terminals.
- Signal connection: In terms of the signal, the user inputs a force on the trigger releasing a signal to the mechanism to allow electrical flow from the power cord to the trigger and into the motor.
- Importance and performance influence of the connection: The user controls the trigger to allow the power cord to transfer electrical energy from the outlet it is plugged into, to the trigger which then transfers this energy to the motor. Without this connection there would be no energy input into the system and therefore the user would be unable to use or control the device. In order to allow for a sufficient trigger system which will have a large amount of force and stress upon it over the life of the product, the strength of the trigger material must be large enough to withstand the constant pressure of the users hand as well as the vibration of the system itself. This must be done to avoid any deterioration or breaking of the trigger thus leaving the product useless until fixed or replaced. The power cord must also be designed in a way to prevent any tearing or possible electrocution. This can be done with thicker rubber coating around the wiring and a strong connection into the hammerdrill itself.
- Global connection influence: Based on the plug on the power cord, the drill can only be used in North America due to the outlet. In order to use the drill in another country or continent, a new cord plug would have to be incorporated.
- Societal connection influence: For safety, durable wiring must be used to prevent tearing and therefore possible electrocution.
- Economic connection influence: The components and subsystem are housed and protected on the inside of the drill. To be cost efficient, plastic is utilized to minimize cost instead of using a metal casing.
- Environmental connection influence: The cord and trigger assembly must be made recyclable in order to dispose of if replacements are needed as well as at the products end life.
Trigger assembly connection to the motor
- Physical connection: The trigger assembly is connected by two wires to the positive and negative power terminals on the motor. This allows electrical energy to be transferred into the motor. The terminals are connected to the motor by screws.
- Energy connection: The electrical energy from the power cord which was transferred to the trigger assembly is then sent to the power terminals connected to the back of the motor, powering it.
- Signal connection: The users input force on the trigger signals the trigger assembly to transfer electrical energy to the motor so it can be powered.
- Importance and performance influence of the connection: The transfer of energy must be regulated from the trigger by the user so the drill will only run when the user wants it to. The motor cannot be powered without this function. The connection between the wiring of motor and trigger must be strong enough as to not tear or become disconnected due to vibrations in the system. Therefore a thick coating should be implemented around the wiring as well as a sturdy connection between the wires and the motor terminals; solder would suffice for example.
- Global connection influence: The region of manufacturing must be considered when choosing a motor and trigger system. The availability of the motor parts and plastics integrated into the system should be implemented in the design.
- Societal connection influence: The user directly interacts with the trigger therefore it must be designed ergonomically to fit the users fingers and be comfortable for use of a long period of time.
- Economic connection influence: Mass manufacturing techniques for parts of the trigger and motor must be taken into account in order to reduce overall production costs.
- Environmental connection influence: It must be considered whether or not the motor and plastics used can be recycled if they must be replaced or discarded at the end life of the product.
Motor assembly connection to the gearbox assembly
- Physical connection: The motor assembly is connected by the shaft and ball bearing to the gearbox assembly. The gearbox contains a set of 3 gears and an additional shaft.
- Energy connection: The electrical energy transferred into the motor creates rotational energy which turns the gears in the assembly.
- Signal connection: The motor can only be powered through the user input of the trigger signaling energy transfer.
- Importance and performance influence of the connection: The function of this sub system connection is required to convert the electrical energy into rotational energy of the gears through the motor shaft. The motor shaft and the gears on the gearbox should have the same thread size in order to connect but also leave a gap between the teeth to allow for movement of the system. If the teeth are too close together, the gears could lock up and cause system failure. The shafts and gears should also be well supported in the system to protect against loosening due to vibrations caused by the product.
- Global connection influence: The availability of the gears and gearbox integrated must be taken into account. Materials and manufacturing methods based on the region of production determines the end product.
- Societal connection influence: The noise of the motor and gearbox turning must have met the noise standards of the user and stander-by. An extremely loud tool running for a long period of time would begin to get aggravating for the user and anyone else in the area.
- Economic connection influence: Mass manufacturing and wide spread availability of the motor and gearbox must be made to insure it is cheaper to produce the parts in mass quantities.
- Environmental connection influence: The gears, motor, and gearbox must be recycled if necessary to replace as well as the end life of the product. Therefore recyclable or reusable materials must be implemented to reduce waste.
Gearbox assembly connection to the chuck assembly
- Physical connection: The small shaft and gears connects to the chuck assembly which in turn rotates the drill bit.
- Energy connection: The rotational energy of the gears and shaft is transferred to the chuck assembly housing the drill bit so it can be rotated as well.
- Signal connection: The users input force on the trigger sends a signal to transfer converted rotational energy from the motor to the gears and shafts driving the chuck to spin the drill bit.
- Importance and performance influence of the connection: Without this connection the drill bit housed by the chuck would not rotate, therefore causing the system to be useless. Likewise with the motor shaft and the gears on the gearbox, the thread size between the gears on the gearbox and the gears on chuck shaft should be the size as well. A gap between the teeth must be implemented to allow for movement of the system but prevent a lock up of the system. The shafts and gears should be well supported and be a strong material like steal to prevent any loosening with vibrations in the system as well as house the drill bit in the chuck.
- Global connection influence: The availability of parts incorporated into the chuck must be based on the region in which the manufacturing of the product takes place. The design must revolve around what is readily available.
- Societal connection influence: The assembly of changing out bits in the chuck by the user must meet customer requirements of being easy and quick. The user would not want to struggle and take a large amount of time to switch out a bit, especially if the product is being used for a quick fix job.
- Economic connection influence: Mass manufacturing of the gearbox and chuck must be used in order to allow for replacement parts and low initial costs by ordering in mass quantities.
- Environmental connection influence: The chuck and gearbox must be recyclable in order to reduce pollution and waste if they must be replaced or discarded in the end life of the product.