4.1 FR Levels
a. FR Levels are related to operation of the part at the stress level specified by the applicable ER specification
b. Provisions are made for the FR levels ranging from 1.0 to 0.001 percent per 1000 components part hours. In the event the existing FR Level of a current product is higher than 1.0 percent, an additional level (level 'L') shall be added which will represent the state-of-the-art for the part.
c. Although the failure is expressed in percent per 1000 hours (%/1000 hour) throughout this standard, sampling plans and statistical tables may be used for the FR levels expressed either in terms of percent per 1000 cycles, operations, or in terms of duty cycle and stress level.
Replaced/Superseded by document(s)
|File||MIME type||Size (KB)||Language||Download|
|MIL STD- Failure Rate Sampling Plans and Procedures.pdf||application/pdf||1.99 MB||English||DOWNLOAD!|
This standard provides procedures for failure rate (FR) qualification, sampling for establishing and maintaining FR levels at selected confidence levels, and Lot conformance inspection procedures associated with FR testing for the purpose of direct reference in appropriate military electronic parts established reliability (ER) specifications. Figures and tables throughout this standard are based on exponential distribution. Weibull distribution will be acceptable in certain components such as capacitors. Use of Weibull distribution for any component must be approved by the qualifying activity. This standard also provides guidance to specification writers in the use of this standard (see appendix) and reference material for users of ER parts.