1. Design Criteria and Constraints
Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Design Criteria and Constraints
Design is directed toward human beings. To design is to solve human problems by identifying them and executing the best solution.
Ivan Chermayeff
Introduction to Engineering Design
© 2012 Project Lead The Way, Inc.

2. Design Criteria and Constraints
Performance
Product Size and Shape
Aesthetics
Materials
Safety and legal Issues
Ergonomics
Environment
Life Cycle
Durability and Maintenance
Design Constraints
Measurable Values

3. Example Design Specification
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Example Design Specification
Design a pet restraint system to keep a dog safe.

4. Criteria and Constraints
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Criteria and Constraints
Specific, concise written information about the requirements that must be met in order to attain the intended outcome
Must be specific and unambiguous
Client must be involved

5. Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Design Criteria
The explicit requirements that a product must meet in order to be successful
Used to evaluate a product’s potential to be successful
Used to create testing procedures
May address
Performance
Maintenance
Product Size and Shape
Customer Needs
Aesthetics
Others
Materials
Safety and Legal Issues
Ergonomics
Environment
Life Cycle

6. Performance Specify the function of the product
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Performance
Specify the function of the product
What will the product need to do?
Example: When designing a special fork lift for a warehouse,
How will the vehicle be powered?
What is the maximum speed?
On what surfaces must the vehicle operate?
What turning radius is required?
What are the dimensions of the cargo to be lifted?
What is the maximum load to be lifted?
How high must the cargo be lifted and stored?
©iStockphoto.com

7. Product Size and Shape Form Dimensions Weight Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Product Size and Shape
Form
Dimensions
Weight

8. Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Aesthetics
The way that a product looks will affect marketability, especially for a consumer item.
Color
Surface Treatment
Shape
Material

9. Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Materials
Often chosen by the design team to meet criteria, but sometimes dictated based on special needs or availability
©iStockphoto.com

10. Safety and Legal Issues
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Safety and Legal Issues
Human health and safety
Product liability laws expose manufacturers to lawsuits if their products fail
©iStockphoto.com
©iStockphoto.com

11. Ergonomics The science of designing according to human needs
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Ergonomics
The science of designing according to human needs
Products should be designed for human comfort, efficiency, safety, and ease of use

12. Environment Operating Environment
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Environment
Operating Environment
Product will encounter a wide range of environments from manufacture to operation by the customer
Temperature range
Corrosive environments
Dust or dirt
Pressure and humidity
Vibration and noise
Degree of abuse

13. Environment Global Environment
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Environment
Global Environment
What affect will the product have on the Earth’s environment?
How will the product be disposed of?

14. Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Life Cycle
Service Life: The length of time a product is expected to operate properly without need for repair
Product Life: The length of time a product will undergo production before being replaced with a newer version
Planned Obsolescence: A manufacturing decision by a company to make consumer products in such a way that they become out-of-date or useless within a known period.

15. Durability and Maintenance
Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Durability and Maintenance
Product should not need major repairs within the service life
Routine maintenance should be planned
Routine maintenance should be easy
Plan for access
Necessary tools
Replacement parts

16. Presentation Name
Engineering Design and Development
Unit # – Lesson #.# – Lesson Name
Design Constraints
The limits on the design and production of a product
Resources (people, equipment, etc.)
Budget
Time
Energy
Materials
Manufacturing Process
Others

17. Presentation Name
Course Name
Unit # – Lesson #.# – Lesson Name
Measurable Values
Each criteria and constraint should be expressed with specific or measurable value(s).
Evaluation of Conceptual Designs
Testing Criteria

18. Measurable Values
Poor Specification: The device must warn the driver and slow the vehicle when the car is too close to an object. Better: Within one second the device must warn the vehicle driver and disengage the cruise control when the car attains a distance of less than 50 ft directly between itself and another vehicle.

19. Image Resources
Microsoft, Inc. (n.d.). Clip art. Retrieved from
iStockphoto. Retrieved from