Forum: Reliability & Maintainability Questions and Answers
Posted by: Ravinder (email@example.com )
Date posted: Wed Jun 4 6:56:48 US/Eastern 2003
Subject: Reliability testing
Can you please help me out in Reliability testing?
What is the difference between Reliability testing and testing as per some standard? Can we find out the Warranty period from the Reliability testing data for oil seals?
Posted by: Anuradha (firstname.lastname@example.org )
Date posted: Sat May 31 2:16:09 US/Eastern 2003
Subject: PCB laminate Failure modes while we use SMT
I had carried out reliability prediction for a circuitry.I am using chip resistors (quarter watt,) and capacitors that doesn't dissipate heat much.Reliability prediction software is asking for PCB Substrate .For FR4 Material iam getting 58 FITS,There is one more calssification Epoxy Glass for which i am getting 22 FITS. As i know FR4 is made of Epoxy and woven glass.What factor makes the huge difference in Failure rate of PCB Substrate.What are the factors (like Tg,) that will affect reliability of PCB laminate especially when we use SMT (SMD components)
Posted by: Gupta (email@example.com )
Date posted: Wed May 28 1:05:53 US/Eastern 2003
Subject: Usage of Reliability
While Reliability predication, how do i know that the component is following
1. Exponential Reliability or 2. Weibull reliability or 3. Log Normal Reliability. Is it avl. in PRISM package. If Suppose I am taking the field failure data, than how come I decide it.
Posted by: Anil Kumar (firstname.lastname@example.org )
Organization:Centre For Reliability
Date posted: Thu May 22 6:39:50 US/Eastern 2003
Subject: Life of product
How do you evaluate usefull life of a product. Is there any relationship between usefull life and MTBF of a product. ALT is used to determine life of components, Is there any accelerated process or statistical method to determine usefull life of product. Please reply at the earliest.
Posted by: Shanta
Date posted: Tue May 20 9:54:10 US/Eastern 2003
Subject: Resistor RACRates Model - PRISM
This question is in reference to the Resistor RACRates Model in PRISM software. It requires a combination of thermal stress (in the form of calculated element temperature) and rated power parameters. Depending on the Element Temperature Calculation option chosen, the user is required to enter different pieces of data. If you select Option 5, you need to enter delta-temperature stress, rated power dissipation and actual power dissipation. What is delta temperature stress (Delta-T)? How is it different from the other 4 options which use ambient temperature, temperature rise, ThetaJC (or ThetaJA)*P?