Remote control tarantula
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==Design for manufacturing and assembly== | ==Design for manufacturing and assembly== | ||
==Failure mode effects analysis== | ==Failure mode effects analysis== | ||
+ | {| class="wikitable" <hiddentext>generated with [[:de:Wikipedia:Helferlein/VBA-Macro for EXCEL tableconversion]] V1.7<\hiddentext> | ||
+ | |- style="background-color:#C0C0C0;font-weight:bold" align="center" | ||
+ | | width="77" height="63" | Item & Function | ||
+ | | width="121" | Potential failure mode | ||
+ | | width="131" | Potential failure effects | ||
+ | | width="34" | SEV | ||
+ | | width="139" | Potential causes | ||
+ | | width="32" | OCC | ||
+ | | width="152" | Design controls | ||
+ | | width="33" | DET | ||
+ | | width="58" | RPN | ||
+ | | width="103" | Actions recommended | ||
+ | | width="46" | Responsibility | ||
+ | | width="46" | Actions Taken | ||
+ | | width="27" | New SEV | ||
+ | | width="32" | New OCC | ||
+ | | width="32" | New DET | ||
+ | | width="34" | New RPN | ||
+ | |||
+ | |- | ||
+ | | height="123" | Internal Electronics Components | ||
+ | | | Wiring Disconnect | ||
+ | | | Complete loss of function. Diminished control of toy. Unreliable operation. | ||
+ | | align="center" | 8 | ||
+ | | | * Temperature Cycling * Jarring of internal components causing disconnect Disassembly by user | ||
+ | | align="center" | 4 | ||
+ | | | Close fitting parts allowing for minimal movement. Connection check post-assembly. | ||
+ | | align="center" | 6 | ||
+ | |style="font-weight:bold" align="center" | 192 | ||
+ | | | Increased solder for vulnerable connections. More chassis/electronics connection points. Warning to user of possible consequences of disassembly. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 6 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 6 | ||
+ | |style="font-weight:bold" align="center" | 72 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Power Train | ||
+ | | | Wearing of gears or motor. Loose mounting allowing for vibration. | ||
+ | | | *Increased noise during operation causing ** loss of realism ** noise irritation to user ** reduction in "startling" ability | ||
+ | | align="center" | 4 | ||
+ | | | Wear on motors. Misalignment causing additional wear. Insufficient or loss of lubrication. | ||
+ | | align="center" | 5 | ||
+ | | | Standardized lubrication application. Quality control of gears and mounting. | ||
+ | | align="center" | 6 | ||
+ | |style="font-weight:bold" align="center" | 120 | ||
+ | | | Improved gear quality. Running motor at lower speeds. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 4 | ||
+ | | align="center" | 3 | ||
+ | | align="center" | 6 | ||
+ | |style="font-weight:bold" align="center" | 72 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Gears | ||
+ | | | Gear slip | ||
+ | | | Limited or complete loss of functionality. Toy may stop working entirely or lose functions such as turning, leg movement or forward movement. | ||
+ | | align="center" | 6 | ||
+ | | | Gear misalignment. Unexpected load on drive train. | ||
+ | | align="center" | 4 | ||
+ | | | Textured axels. Quality controls of gear supply and positioning. | ||
+ | | align="center" | 5 | ||
+ | |style="font-weight:bold" align="center" | 120 | ||
+ | | | Higher density gears. Adhesive applied to axles. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 6 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 5 | ||
+ | |style="font-weight:bold" align="center" | 60 | ||
+ | |||
+ | |- | ||
+ | | height="123" valign="top" | Motor | ||
+ | | valign="top" | Overheating resulting in seize. | ||
+ | | valign="top" | Temporary or permanent failure of motor. Loss of functionality during motor malfunction. | ||
+ | | align="center" valign="top" | 7 | ||
+ | | valign="top" | Prolonged use environmental conditions (moisture, heat, particulates). | ||
+ | | align="center" valign="top" | 3 | ||
+ | | valign="top" | Some protection from environment by body. Low capacity batteries preventing prolonged use. | ||
+ | | align="center" valign="top" | 5 | ||
+ | |style="font-weight:bold" align="center" | 105 | ||
+ | | valign="top" | Better use of internal space to improve heat dissipation. Further sealing of body from environment. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 7 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 5 | ||
+ | |style="font-weight:bold" align="center" | 70 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Internal Electronics Components | ||
+ | | | Short circuit | ||
+ | | | Complete loss of function. Diminished control of toy. Unreliable operation. | ||
+ | | align="center" | 7 | ||
+ | | | Exposure to moist environment immersion in water | ||
+ | | align="center" | 5 | ||
+ | | | Limited routes of exposure from internal components to environment. Warning to user of potential effects of moisture on device. | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 105 | ||
+ | | | Minimize number of chassis openings to environment. Seal joints with moisture-resistant adhesives or seal sensitive electronic components. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 6 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 36 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Drive Wheel Mount | ||
+ | | | Mount is unable to pivot | ||
+ | | | Inability to either turn or go straight consistently. User is unable to control movement of Tarantula to reasonable expectations. | ||
+ | | align="center" | 6 | ||
+ | | | Clogging of slots that mount slides in. Misalignment of parts caused by jarring. Off specification parts causing jamming. | ||
+ | | align="center" | 4 | ||
+ | | | Recessed slots. Lubricated parts. | ||
+ | | align="center" | 4 | ||
+ | |style="font-weight:bold" align="center" | 96 | ||
+ | | | Sealing of slots to outside environment. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 6 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 4 | ||
+ | |style="font-weight:bold" align="center" | 48 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Hair Covering | ||
+ | | | Flaking of hair off of body | ||
+ | | | Decreased realism Hair shedding onto environment | ||
+ | | align="center" | 3 | ||
+ | | | Wear from handling/usage Low resilience adhesive | ||
+ | | align="center" | 10 | ||
+ | | | Lack of hair on parts frequently in contact with other surfaces | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 90 | ||
+ | | | Improved adhesive or hair quality to limit shedding. Use of textile-type cover to achieve similar realism with more durability. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 3 | ||
+ | | align="center" | 5 | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 45 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Remote Control | ||
+ | | | Interference with other RC devices | ||
+ | | | Inability to independently control other Tarantulas nearby. Decreased control of Tarantula depending on nearby radio-emitters | ||
+ | | align="center" | 5 | ||
+ | | | Same frequency use by other devices. Single frequency use across all Tarantulas | ||
+ | | align="center" | 8 | ||
+ | | | Use of frequency that is uncommon in other devices. | ||
+ | | align="center" | 2 | ||
+ | |style="font-weight:bold" align="center" | 80 | ||
+ | | | Cycle tarantula frequencies among toys. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 5 | ||
+ | | align="center" | 2 | ||
+ | | align="center" | 2 | ||
+ | |style="font-weight:bold" align="center" | 20 | ||
+ | |||
+ | |- | ||
+ | | height="123" | Legs | ||
+ | | | Legs become fixed in lifted position. | ||
+ | | | Legs no longer move as Tarantula does. Novelty of toy diminished. Realism of toy (and thus startling effect) diminished. | ||
+ | | align="center" | 4 | ||
+ | | | Low tolerance on hinge. Environmental conditions causing jamming. | ||
+ | | align="center" | 5 | ||
+ | | | Simplified leg mechanism. Simple maintenance by user. | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 60 | ||
+ | | | What are the actions for reducing the occurrence of the cause or for improving its detection? You should provide actions on all high RPNs and on severity ratings of 9 or 10. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 10 | ||
+ | | align="center" | 10 | ||
+ | | align="center" | 10 | ||
+ | |style="font-weight:bold" align="center" | 1000 | ||
+ | |||
+ | |- | ||
+ | | height="123" | LED Eyes | ||
+ | | | LED eyes become dim, asymmetrical or unlit. | ||
+ | | | Reduction of novelty or "startling" aspects. Inability to visually recognize when the toy is "on" resulting in excess power consumption | ||
+ | | align="center" | 3 | ||
+ | | | Dirt or other particles blocking eye holes. LED defect. Disconnect from power source. Internal shifting of LED. | ||
+ | | align="center" | 6 | ||
+ | | | Bright LED's. Multiple enclosed eye holes. Cleaning by user. | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 54 | ||
+ | | | What are the actions for reducing the occurrence of the cause or for improving its detection? You should provide actions on all high RPNs and on severity ratings of 9 or 10. | ||
+ | | | N/A | ||
+ | | | N/A | ||
+ | | align="center" | 3 | ||
+ | | align="center" | 4 | ||
+ | | align="center" | 3 | ||
+ | |style="font-weight:bold" align="center" | 36 | ||
+ | |||
+ | |} | ||
==Design for environment== | ==Design for environment== |
Revision as of 00:32, 24 September 2007
Contents |
Executive summary
Customer needs
Function
The Tarantula is a variant of commonly seen remote controlled toys. The user holds a controller which sends radio signals to the Tarantula and controls its movement. The appeal of this toy is the novelty of a large moving spider as a remote controlled vehicle. Also, the realism of the device adds to the user’s enjoyment by allowing him or her to scare others with it.
Forward Locomotion
The controller only has two outputs, forward and back. During “forward” the motor runs in a clockwise direction engaging the drive wheels through a gear system. The drive wheels are under the head of the spider, and pivot to steer. A second set of wheels attached to the battery cover support the abdomen of the spider, but do not contribute to steering or propulsion. The drive wheels are vertically offset from each other to mimic a “crawling” motion and add to the realism. Due to the high gear ratio, the movement is slower than most RC toys, similar to what one would expect of an actual spider. However, the toy only functions well on very flat surfaces, and will become stuck on carpet or small obstacles.
Leg Movement
When the motor is engaged, a turn table in the head of the spider also spins. This table is cam shaped which causes it to asymmetrically engage 8 levers which are connected to the 8 legs of the spider. As the turn table engages the legs they are lifted up, but pulled back down by gravity as the turn table disengages them. This up and down motion of the legs mimics the crawling of a spider and it is central to the realism and novelty of the product.
Turning
The spider has no specific steering input form the remote control; rather it turns when the motor is running counterclockwise or receiving a “backwards” input. The drive wheels are setup such that depending on the direction the motor is running, the wheels will align to a certain orientation. The drive shaft for the wheels descends vertically from the head of the spider and connects to the drive wheels at a 90° angle. The bracket which holds the axle sits in two slots which allow it to rotate along the axis of the drive shaft. When the motor runs there is a net torque on the drive wheel axle, causing the bracket and axle to rotate if they are able. The wheels turn 45° relative to the centerline of the Tarantula if the motor is running backwards, and point straight ahead if the motor is running forwards. This causes the spider to turn while it is moving backwards, allowing the user to control the eventual destination of the device.
Power Train
The spider is powered by two AAA batteries connected in series. This powers the small motor and electronics (circuit board, LED eyes). The motor is connected to a gearing system with a large gearing ratio by a worm gear. This results in a slower movement, but higher torque on the drive wheels.
Product use
Components
Part # | Part name | QTY | Function | Materials | Manufacturing Process | Picture |
---|---|---|---|---|---|---|
001 | Cover Screws | 13 |
| Steel | Cold headed, Thread Rolled | |
002 | Inner Flat-headed screw | 2 |
| Steel | Cold headed, Thread rolled | |
003 | Battery Cover | 1 |
| Plastic | Injection Molded, hand modified | |
004 | Back Wheel housing | 1 |
| Plastic | Injection Molded | |
005 | Back Wheel | 2 |
| Plastic | Injection Molded, smoothed | |
006 | Small Leg | 4 |
| Plastic | Injection Molded | |
007 | Medium Leg | 2 |
| Plastic | Injection Molded | |
008 | Large leg | 2 |
| Plastic | Injection Molded | |
009 | Feelers | 2 |
| Plastic | Injection Molded | |
010 | Driving Wheel 1 | 1 |
| Plastic | Injection Molded, smoothed | |
011 | Driving Wheel 2 | 1 |
| Plastic | Injection Molded, smoothed | |
012 | Plastic Protection housing | 1 |
| Plastic | Injection Molded | |
013 | Back Wheel Axle | 2 |
| Steel | Cut wire, smoothed | Image:RC Tarantula Part 013.jpg |
014 | Battery Cover Washer | 1 |
| Plastic | Punched | Image:RC Tarantula Part 014.jpg |
015 | Gear 1 | 2 |
| Plastic | Injection Molded | |
016 | Gear 2 | 1 |
| Plastic | Injection Molded | |
017 | Gear 3 | 2 |
| Plastic | Injection Molded | |
018 | Gear 4 | 1 |
| Plastic | Injection Molded | |
019 | Axle 1 | 1 |
| Steel | Cut wire, smoothed | |
020 | Axle 2 | 1 |
| Steel | Cut wire, smoothed | |
021 | Axle 3 | 1 |
| Steel | Cut wire, smoothed | |
022 | Axle 4 | 1 |
| Steel | Cut wire, smoothed, stamped rough areas | |
023 | Axle 5 | 1 |
| Steel | Cut wire, smoothed, stamped rough areas | |
024 | Axle Cap | 1 |
| Plastic | Injection Molded | Image:RC Tarantula Part 024.jpg |
025 | Switch Assembly | 1 |
| Circuit Board (silicon), metal wires, plastic switch | Assembly | |
026 | Switch Cover | 1 |
| Plastic | Injection Molded | |
027 | Motor Assembly | 1 |
| Metal wiring, magnets, Metal casing, plastic gearing | Assembly | |
028 | Circuit Board Assembly | 1 |
| Circuit Board (silicon), metal wires | Assembly | |
029 | LED Assembly | 1 |
| Circuit (silicon), metal wires, LED | Assembly | |
030 | Tarantula exterior bottom | 1 |
| Plastic | Injection Molded, hand modified | |
031 | Tarantula exterior top | 1 |
| Plastic | Injection Molded, hand modified | |
032 | Battery Connector | 1 |
| Steel | Cut sheet metal | Image:RC Tarantula Part 032.jpg |
033 | Battery + connector | 1 |
| Steel | Cut sheet metal | Image:RC Tarantula Part 033.jpg |
034 | Battery - connector | 1 |
| Steel | Cut sheet metal | Image:RC Tarantula Part 034.jpg |
035 | Metal screw receiver | 1 |
| Steel | threaded cylinder | Image:RC Tarantula Part 035.jpg |
036 | Drive Wheel Mount | 1 |
| Plastic | Injection Molded |
Design for manufacturing and assembly
Failure mode effects analysis
Item & Function | Potential failure mode | Potential failure effects | SEV | Potential causes | OCC | Design controls | DET | RPN | Actions recommended | Responsibility | Actions Taken | New SEV | New OCC | New DET | New RPN |
Internal Electronics Components | Wiring Disconnect | Complete loss of function. Diminished control of toy. Unreliable operation. | 8 | * Temperature Cycling * Jarring of internal components causing disconnect Disassembly by user | 4 | Close fitting parts allowing for minimal movement. Connection check post-assembly. | 6 | 192 | Increased solder for vulnerable connections. More chassis/electronics connection points. Warning to user of possible consequences of disassembly. | N/A | N/A | 6 | 2 | 6 | 72 |
Power Train | Wearing of gears or motor. Loose mounting allowing for vibration. | *Increased noise during operation causing ** loss of realism ** noise irritation to user ** reduction in "startling" ability | 4 | Wear on motors. Misalignment causing additional wear. Insufficient or loss of lubrication. | 5 | Standardized lubrication application. Quality control of gears and mounting. | 6 | 120 | Improved gear quality. Running motor at lower speeds. | N/A | N/A | 4 | 3 | 6 | 72 |
Gears | Gear slip | Limited or complete loss of functionality. Toy may stop working entirely or lose functions such as turning, leg movement or forward movement. | 6 | Gear misalignment. Unexpected load on drive train. | 4 | Textured axels. Quality controls of gear supply and positioning. | 5 | 120 | Higher density gears. Adhesive applied to axles. | N/A | N/A | 6 | 2 | 5 | 60 |
Motor | Overheating resulting in seize. | Temporary or permanent failure of motor. Loss of functionality during motor malfunction. | 7 | Prolonged use environmental conditions (moisture, heat, particulates). | 3 | Some protection from environment by body. Low capacity batteries preventing prolonged use. | 5 | 105 | Better use of internal space to improve heat dissipation. Further sealing of body from environment. | N/A | N/A | 7 | 2 | 5 | 70 |
Internal Electronics Components | Short circuit | Complete loss of function. Diminished control of toy. Unreliable operation. | 7 | Exposure to moist environment immersion in water | 5 | Limited routes of exposure from internal components to environment. Warning to user of potential effects of moisture on device. | 3 | 105 | Minimize number of chassis openings to environment. Seal joints with moisture-resistant adhesives or seal sensitive electronic components. | N/A | N/A | 6 | 2 | 3 | 36 |
Drive Wheel Mount | Mount is unable to pivot | Inability to either turn or go straight consistently. User is unable to control movement of Tarantula to reasonable expectations. | 6 | Clogging of slots that mount slides in. Misalignment of parts caused by jarring. Off specification parts causing jamming. | 4 | Recessed slots. Lubricated parts. | 4 | 96 | Sealing of slots to outside environment. | N/A | N/A | 6 | 2 | 4 | 48 |
Hair Covering | Flaking of hair off of body | Decreased realism Hair shedding onto environment | 3 | Wear from handling/usage Low resilience adhesive | 10 | Lack of hair on parts frequently in contact with other surfaces | 3 | 90 | Improved adhesive or hair quality to limit shedding. Use of textile-type cover to achieve similar realism with more durability. | N/A | N/A | 3 | 5 | 3 | 45 |
Remote Control | Interference with other RC devices | Inability to independently control other Tarantulas nearby. Decreased control of Tarantula depending on nearby radio-emitters | 5 | Same frequency use by other devices. Single frequency use across all Tarantulas | 8 | Use of frequency that is uncommon in other devices. | 2 | 80 | Cycle tarantula frequencies among toys. | N/A | N/A | 5 | 2 | 2 | 20 |
Legs | Legs become fixed in lifted position. | Legs no longer move as Tarantula does. Novelty of toy diminished. Realism of toy (and thus startling effect) diminished. | 4 | Low tolerance on hinge. Environmental conditions causing jamming. | 5 | Simplified leg mechanism. Simple maintenance by user. | 3 | 60 | What are the actions for reducing the occurrence of the cause or for improving its detection? You should provide actions on all high RPNs and on severity ratings of 9 or 10. | N/A | N/A | 10 | 10 | 10 | 1000 |
LED Eyes | LED eyes become dim, asymmetrical or unlit. | Reduction of novelty or "startling" aspects. Inability to visually recognize when the toy is "on" resulting in excess power consumption | 3 | Dirt or other particles blocking eye holes. LED defect. Disconnect from power source. Internal shifting of LED. | 6 | Bright LED's. Multiple enclosed eye holes. Cleaning by user. | 3 | 54 | What are the actions for reducing the occurrence of the cause or for improving its detection? You should provide actions on all high RPNs and on severity ratings of 9 or 10. | N/A | N/A | 3 | 4 | 3 | 36 |
Design for environment
EIOLCA
The amount of environmental impact attributable to a single Tarantula is relatively negligible. But when the large volume of numbers produced is taken into account, the amount of pollutant emissions, economic demands, and energy needs become a larger factor to consider. The apparently environmentally harmless product becomes more a larger problem when considered in the grander scale of manufacturing and production.
The method used to calculate the environmental and economic impact of the Tarantula involves the use of data provided through the Economic Input-Output Life Cycle Assessment (EIO-LCA) database. In order to get a proper appreciation of the impact of the product, all calculations and measurements are done in terms of millions of dollars of economic activity. The database compiles information pertaining to the economic demands, pollutants emitted, energy demands, even the labor needs for certain sectors of different industries. Once a sector’s impact is calculated, the information pertaining to the contributing factors for each million dollars of activity can be accessed and compared.
Production of the Tarantula pertains primarily to sector 33930 - Dolls, Toys, and Game Manufacturing. However, over the lifetime of the product’s use, multiple purchases of batteries are required. As a result, the economic and environmental impact of the product is also linked to sector 335912 - Primary Battery Manufacturing. The focus of this analysis is to observe the main sources of emissions and demand for energy. The types of emissions observed are greenhouse gases, conventional air pollutants, and toxic releases.
For sector 33930, the primary consumer of energy is power generation itself. It consumes nearly three times the energy as the next two sectors, which are toy manufacturing and paperboard mills. These three sectors combined contribute for approximately half of the total energy required, amounting to 3.99 TJ/$1 Million for Production. The non-toxic emissions produced are also primarily attributable to power generation. However, the toxic releases caused by sector 33930 stem from the chemical nature of the type of manufacturing methods used. Of the 46.4kg/$1M, approximately 20 kg is caused by toy manufacturing and plastics material manufacturing.