SRC Forum - Message Replies

Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

Back to message list Show all replies Topics List About this forum
Original Message:

Date posted: Mon Mar 19 9:44:26 US/Eastern 2001
How are reliability pridictions made for 1 off, job lots, batches and maxx production


Subject: Performing reliability predictions
Reply Posted by: David Dylis ( )
Organization: Reliability Analysis Center (RAC)
Date Posted: Mon Mar 26 11:31:02 US/Eastern 2001
I would recommend that the RAC PRISM tool be used to assess the reliability of systems of the type that you describe. PRISM is a new software tool that ties together several tools into a comprehensive system reliability prediction methodology. The PRISM concept accounts for the myriad of factors that can influence system reliability, combining all those factors into an integrated system reliability assessment resource. Process-related variability around an assembly or system failure rate is implemented within PRISM via a process grading methodology. By answering a series of questions within a specific grade type, the user establishes a scoring profile whose total value is translated into a quantitative pi-factor multiplier for that type that impacts the predicted failure rate. Process grade types currently defined within PRISM are: Design, Manufacturing, Parts Quality, System Management, CND, Induced, Wearout, Growth and Infant Mortality. This grading is accomplished by assessing the processes in a self audit-like fashion. Any or all of these process grade types can be assessed and graded. If the user chooses not to address a specific process grade, the model simply reverts to the default “average” value. PRISM was developed to overcome inherent limitations in MIL-HDBK-217 that is no longer being actively maintained or updated by the Department of Defense (DoD). PRISM fills this void by providing a superior approach for reliability modeling under a broad range of applications. For more information on the RAC PRISM, please visit If you have additional questions feel free to call or Email me. David Dylis Data and Information Manager Reliability Analysis Center (RAC) 201 Mill St. Rome, NY 13440-6916 Phone: (315) 339-7055 Fax: (315) 337-9932 Email: Web Site:

Reply to this message