- GE498 Senior Design II
Realistic Design Constraints
Realistic Design Constraints
January 16, 2007 GE 498 Senior Design II
GE498 - Senior Design II
Realistic Design Constraints
Engineering standards Please recall the following main points from the GE 497 engineering standards lecture. Standards are detailed documents that may be rules, testing methods, definitions, recommended practices, or specifications that promote uniformity for engineering design, industrial practices, and terminology. Standards promote safety, technological development, ease of interface, uniform performance, fairness, and professional development. Some common standards organizations include National Institute of Standards, Underwriters Laboratory, ASME, International Standards Organization, and American National Standards Institute.
GE498 - Senior Design II
Realistic Design Constraints
Realistic design constraints You must also consider the following realistic design constraints, as appropriate: Health and safety Ethics Sustainability Economic Environmental Social factors Manufacturability
GE498 - Senior Design II
Realistic Design Constraints
Health and safety considerations Engineering standards promote the design of safe electrical and mechanical engineering systems A Failure Modes and Effects Analysis (FMEA) can be used to identify and eliminate potentially hazardous design features. Remember, your primary consideration must be the safety, health, and welfare of the public.
GE498 - Senior Design II
Realistic Design Constraints
Health and safety considerations FMEA example
Lawn Mowing Process (Safety) Lawn Mowing Processes Fill tank with gas Potential Failure Spill gas Start fire Start lawn mower Push across lawn Slip Slip Loose control of mower Pull across foot Cut grass with blade Throw debri Cut appendage Maintenance tasks Add oil Sharpen blade Change spark plug Clean blade Potential Effect Environmental concerns Create fire hazard Burns Loss of property Injury Injury Property Damage Injury Severity 5 8 8 8 8 9 9 9 Potential Causes Loose nozzle Loose balance, not flat surface Loose balance, wet grass Spark Smoking Wet grass Cord breaks Wet grass Distracted Loose balance, incline Loose balance, wet grass Distracted Backing up Guard off Guard off Discharge aimed at someone Guard off Insert hand under mower Guard off Distraction Lack of information Distraction Probability Current Design Detection RPN Action Controls 5 Manual 10 250 2 Manual 10 200 2 Manual 10 200 2 Manual 10 160 5 10 400 Add warning labels 4 2 4 4 2 2 4 7 3 3 6 3 3 6 6 6 6 Manual Lab testing Manual Manual Dead switch Dead switch Manual Manual Manual Manual Manual Manual Manual Manual Manual Manual Manual 10 3 10 10 6 6 10 10 10 10 10 10 10 10 10 10 10 320 48 320 320 96 96 360 560 Can we add detector 270 to sense foot and 270 kill blade motion? 540 Deflector? Flap? 270 270 480 560 180 420
Touch hot engine Slip Electrical shock Slip
Burn Cut hand Cut hand
8 7 3 7
Companies would have job safety analysis for each of the processes and hazardous energy control procedures for each maintenance operation.
GE498 - Senior Design II
Realistic Design Constraints
Ethical considerations In GE 301 and GE 497, you studied the ethical implications of engineering work. Are there potentially unethical uses of your project? Does your project promote the safety, health, and welfare of the public?
GE498 - Senior Design II
Realistic Design Constraints
Ethical considerations How might your device be manufactured, marketed and used? Manufactured with child labor?
Will it be marketed to children?
Will it be used to rob a bank?
GE498 - Senior Design II
Realistic Design Constraints
Sustainability A sustainable design is one that balances three considerations Environmental stewardship Social impact Economic feasibility A design that focuses on one or two of these factors at the expense of others is not sustainable
GE498 - Senior Design II
Realistic Design Constraints
Environmental stewardship What Is the environmental impact of the production of this device or product? Are environmentally sensitive materials used? Is toxic waste or hazardous emissions generated?
Pesticides (DDT)
Toxic waste.
GE498 - Senior Design II
Realistic Design Constraints
Environmental stewardship What Is the environmental impact of the operation of this device? Is the device energy efficient? Does it generate greenhouse gases when operated?
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GE498 - Senior Design II
Realistic Design Constraints
Environmental stewardship What is the environmental impact of the end of the devices Life Cycle? Can components be easily separated and recycled?
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GE498 - Senior Design II
Realistic Design Constraints
Environmental BMW stewardship uses a technique known as Design for Disassembly to optimize the recycling of a car at the end of its life cycle.
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GE498 - Senior Design II
Realistic Design Constraints
Social impact What Is the social impact of the production of this device? Will its production expose workers to hazardous conditions such as chemicals, heat, and ergonomic issues? Will its production provide workers with an opportunity to earn a living wage? Steel Mill
Garment sweatshop
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GE498 - Senior Design II
Realistic Design Constraints
Social impact What Is the Social Impact of the Operation of this Device? Is this device likely to be used for purposes that will benefit (or harm) society ? Will your design be broadly accepted (tolerated) by society?
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GE498 - Senior Design II
Realistic Design Constraints
Economic impact What are the economic considerations of the production of this device? Will your company have to purchase and use expensive and specialized equipment? Will its production be extremely labor intensive? Is your project as inexpensive as possible to produce? Motor winding automation
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GE498 - Senior Design II
Realistic Design Constraints
Economic impact What Is the Economic Impact of the Sale and Operation of this Device? Will your project be popular enough to make a profit for your company? How many people will want one? Will your project be durable and maintainable enough that your company will not have a large amount of warranty work?
$ 6,949
$ 779
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GE498 - Senior Design II
Realistic Design Constraints
Economic impact What Is the Economic Impact of End of this Devices Life Cycle? Will the company be responsible for disposal or recycling?
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GE498 - Senior Design II
Realistic Design Constraints
Design for manufacture The traditional approach to design was to throw it over the wall from marketing to design to production. This produced products that were technologically impossible, impractical, or impossible or uneconomical to manufacture. Quality programs, such as ISO 9000, now require crossfunctional product development that integrates marketing, design, and production.
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GE498 - Senior Design II
Realistic Design Constraints
Design for manufacture Simplify the design and reduce the number of parts Reduces product cost and opportunity for error Cuts purchasing, manufacturing, and handling costs Reduces lead times Standardize and use common parts to reduce inventory and stocking costs Design for ease of fabrication Near net shape (investment casting and molding) Design to use standard cutting tools Use a single, retained datum with a single setup
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GE498 - Senior Design II
Realistic Design Constraints
Design for manufacture Design for ease of assembly Design such that parts only assemble one-way Design p...