A flowchart for the design process.
(Adapted from Ref. Used by permission of Charles E. Merrill Publishing Co.)
TABLE 1.1 Design Checklist
1. Function:
A simple statement of the objective
2. Detailed functional requirements:
Required performance stated numerically
3. Operating constraints:
Power supplies Operating procedures Maintenance procedures
4. Manufacturing constraints:
Manufacturing processes available
Development facilities available
Permissible manufacturing cost
Other manufacturing constraints
5. Environment
Ambient temperature
Ambient pressure
Climate
Acceleration
Contaminants
6. Other constraints:
Applicable governmental regulations Legal requirements—patents
Life
Reliability
Other operating constraints
Labor available Delivery program Number required
Installation limitations
Expected operators
Effect on other parts of the parent system
Vibration
Other environmental factors
Applicable standards Possible litigation
SOURCE: Adapted from Leech [1.14].
1.8 STANDARD HANDBOOK OF MACHINE DESIGN
TABLE 1.2 Example of Information Provided on a Design Specification Form
1. Product or job identification number
2. Modification or change number and date
3. Function: In basic terms, what is the function to be performed by the item when
designed?
4. Application: Include the system requiring this application.
5. Origin: When, how, and by whom was the requirement made?
6. Customer’s specification: Identify the customer’s specification and note whether it is in
writing or was oral. If oral, who made it, who in your organization received it, and when
was this done?
7. General related specifications: Identify all general specifications, definitions, standards,
or other useful documents and information that contribute to the design specifications.
8. Safety: Identify standard and special safety precautions or requirements to be included in
design considerations, manufacture, marketing, or usage.
9. Governmental regulations and standards applicable: Identify and list
10. Environment: Identify and list the environmental specifications required using the items
included under “Environment” in Table 1-1 as guidelines.
11. Number required and delivery schedule.
12. Desired cost or price information
13. Functional requirements:
Life Performance requirements with acceptable tolerance
limits
Reliability Servicing, maintenance, or repair restrictions
Unacceptable modes of failure Any other functional requirements
14. Additional relevant information:
Limitations of manufacturing facilities
Special procedural requirements
Any other relevant information
15. Action required: For example, preparation of proposal, preparation of detail drawings,
manufacture of prototypes, or manufacture of full production quantity.
SOURCE: Adapted from Leech [1.14].
uct Safety Act). Litigation has also provided additional emphasis on including safety considerations in design. Even so, the question of how safe a product has to be is very complex and ultimately can be answered only in the courts.
Including safety considerations in the design of a product requires knowledge of the types of hazards that can occur and the application of good design principles to the product involved. One of the appropriate considerations for including safety in design is to recognize that the product will ultimately fail. If this is done, then the product can be designed in such a way that the location and mode of failure are planned and the failure and consequences can be predicted, accommodated, and controlled.
Hazards can be classified as human-caused or non-human-caused. The listings in Tables 1.3 and 1.4 are not meant to be complete or all-inclusive, but they do provide a guide for designers to hazards that they should know, appreciate, and consider in any project. To reduce the effect of these hazards in designing a product, the designer should consider the possible modes of usage; the users, operators, or bystanders; the environment of use; and the functions or requirements of expected use.