Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Original Message:Posted by: S.Arun Kumar (email@example.com )
Date posted: Wed Feb 9 8:02:39 US/Eastern 2005
Subject: PRISM Model for PCBs
We are in the process of predicting the FR for an Electronic Assembly consisting of Through Hole Components and SMT Components. We are using a technique of Mixed model Prediction, in the sense that we use PRISM Models for the Passives and some standard ICs. For Connectors, Crystals & Coils we are using MIL 217FN2. When we want to compute the FR for PCB, we were not able to find a model for it in PRISM. We are Currently using MIL 217FN2 for PCBs. Now the Questions we have are Q1. How do I compute the Failure Rate for the PCBs using PRISM. Q2. In MIL 217FN2 we have Model for PTH and SMT Version of the PCB. My Query is that since we take the solder joint factor, Cycling Rate Factor for most of the components we are using in PRISM, do we need to separately calculate the FR of the PCB (SMT Technology).