Microphone
From DDL Wiki
Contents |
Executive Summary
-Dan
this page needs a fricking backlink!
Engineering_Design_II_-_Conceptualization_and_Realization_Course
Stakeholders
-Luo
yes i am a stakeholder
User Study
-Nakul
Assembly
-Justin
- Note: Refer numbers from the Part List Section
Function of the System
Mechanical Analysis
-Nakul
Parts List
-Dan & Justin
Design for Manufacturing and Assembly (DFMA)
Microphone:
Boom Stand:
The parts that construct the boom stand are mainly constructed of either plastic or steel. Most of these parts are mass produced since stands are very common and high in demand. The few parts that plastic (handle and end of thumbscrews) along with the rubber ends on the bottom are most likely made through injection molding. Injection molding provides a high volume mass production of identical parts with very low tolerance. The initial tooling costs are very high but the unit costs are low (meaning a high initial fixed cost but in exchange the marginal cost per unit is sufficiently low), thus when a large quantity of identical parts are produced injection molding will save money in comparison to other processes.
The counter weight on the end of the boom shaft and the microphone holder are both solid pieces of metal made through the casting process. The counter weight is then glued onto the end of the boom shaft. The casting process (my guess is die casting) has a similar manufacturing feature as injection molding cost-wise. They are generally a high volume production with high initial tooling costs but low unit costs.
Thing on bottom…..casting, plastic thing that was press fit into pipe
All the steel tube components have identical thicknesses and diameter, meaning that they can all be produced by the same machinery while each part is cut into the desired length. The raw steel is cast then made into a pipe by stretching the steel out into a tube. The steel tubes are seamless, which are suitable for the job as the shafts for being strong, durable, and light weight. The exterior of all steel components are sprayed on a metta-black finish for a good look to appeal to the consumers.
DFA:
The assembly of the parts can be either by man or machine. In our opinion, it would make more sense to use man power instead of having the assembly process be automated. To our surprise, the after the stand was dissected and analyzed it took less than 5 minutes for a single person to reassemble everything part together. Pliers were the only tool needed for the process, used for tightening bolts.
Failure Modes and Effects Analysis
Considering ways in which a product could potentially fail is an important part of the design process. All products should be designed so that they are safe and reliable for use. Potential dangers must be eliminated before production. FMEA reports identify potential failure modes and assign corrective measures. Risk priority numbers (RPN) are assigned to each failure mode to assure proper prioritizing. Higher RPNs are addressed first. The scale used for measuring RPN can be found in the Engineering Design textbook by Dieter and Schmidt.
S= Severity of Failure O= Probability of Occurrence D= Detectability of Failure.
Assembly/Parts | Failure Mode | Consequence of Failure | S | Causes of Failure | O | Prevention | D | RPN | Recommendations | Responsibility |
---|---|---|---|---|---|---|---|---|---|---|
On/Off Switch | Soldering Becomes Loose | Microphone will not turn on | 5 | Bad soldering | 2 | N/A | 2 | 20 | Check soldering before assembly | Controls engineer |
Diaphragm | Torn Diaphragm | Inoperable | 5 | Misuse or Outside particles gets inside microphone | 1 | Foam Cover | 2 | 10 | N/A | N/A |
Wire Coil | Torn | Microphone inoperable | 5 | Improper use/production | 1 | Testing during production | 6 | 30 | N/A | Controls Engineer |
Wire Coil | Inadequate coating to separate each wire | Decreased electromagnetic effect | 4 | Improper use/production | 1 | N/A | 8 | 32 | N/A | Controls Engineer |
Magnet | Looses magnetism | Decreased sensitivity of microphone, inoperable | 4 | Over time or microphone is subjected to strong magnetic field | 1 | N/A | 7 | 28 | Don't go near extreme magnetic fields | N/A |
Microphone Housing | Broken | Microphone in pieces, wires exposed | 5 | Impact | 1 | N/A | 1 | 5 | Do not drop on floor after serving someone | N/A |
Microphone Clip | Loose Joint | Unable to orient to desired location | 3 | Loose Screws, wear from use | 6 | N/A | 1 | 18 | Tighten Screws constantly, add friction to joint | Controls Engineer |
Microphone Clip | Broken clip | Unable to attach to microphone | 4 | Improper use, impact | 4 | N/A | 1 | 16 | N/A | N/A |
Boom Stand Screw | Loose fastener | Unable to stay in position, falls down | 7 | Improper use, wear | 3 | Rubber pads inside boom housing | 2 | 42 | Replace rubber pads to ensure boom stays gripped in position | N/A |
Extending Stand | Grip fails | Stand does not stay extended | 7 | Wear from lots of use | 2 | Exploded end | 1 | 14 | Add rubber stoppers or grips | Design Engineer |
Rubber Pads | Worn down thickness | Boom shaft is unstable, gravity overcomes friction force | 3 | Worn pads | 1 | N/A | 1 | 3 | Do not pivot shaft aggressively or unnecessarily | N/A |
Rubber Ends | Torn or lost | Stand may slide | 2 | Worn down ends | 1 | N/A | 1 | 2 | N/A | N/A |
Cord Clip | Broken or lost | Loose Cord | 1 | Misuse | 1 | N/A | 1 | 1 | N/A | N/A |
All steel/metal parts of stand (Stand, tripod legs, boom arm , etc) | Oxidation | Aesthetic value, uncomfortable to touch | 3 | Neglect, exposure to water | 2 | N/A | 1 | 6 | Anti-rust finishing | Controls Engineer |
From the generally low RPNs, we can see that this product is extremely safe and only has one part (falling boom stand) that could potential harm the user. Most problems can be avoided with a product test before packaging.
Design for Environment
In designing a product, it is important to consider the environmental effects along with the consumer. Conducting a Life Cycle Assessment (LCA) can improve the product's environmental-friendliness and reduce costs in the long run.
Toxic Release
This table and graph show the amount of toxic release into the environment. Note that the amount released by specifically the manufacture of audio-video equipment is minuscule compared to the other sectors involved.
Greenhouse Gas Emissions
Greenhouse gases, such as carbon dioxide and chlorofluorocarbons, contribute to the prevalent problem of global warming. With a $1 million injection into the Audio-Video Manufacturing sector, the overall global warming potential (GWP) increase by 574 metric tons of CO2 equivalent.
As we can see from the graph above, the actual audio-video manufacturing process only contributes 19.7 MTCO2E, less than 4% of the total. Most of the emissions come from power supply. If a CO2 tax was passed, the manufacture of audio-video might take a hit, but not as hard as most of the other sectors.
Air Pollutants
Conventional air pollutants such as carbon monoxide largely affect weather patterns like causing smog which in turn can cause respiratory and other health problem in affected areas. Most of the problem comes from power generation and the manufacture of petroleum. Audio-video manufacturing was not even in the top 10 pollutant sources.