Purpose of Burn In test

[bhattalok]

Hello,
I want to know the purpose of the Burn In test.
I understand that it helps to determine early life failures.

The thing I don't understand, if Burn-in is a reliability test then why it is conducted at the Mfg level after the system level products are assembled and ready to ship. Shouldn't it be during the product development phase?

The other questions I have is how different is Burn In from HALT?
Both determine the failure modes for components in a system.

Thanks,
Alok

[Pantelis]

Burn-in at its very simplest is a screening tool. Simply put if a manufactured product has a decreasing failure rate then you run the product in house for some time, this way eliminating early failures at the hand of the customer.

[arunkumar]

Can you please explain detail about Burnin Vs HALT?

[Pantelis]

Well, and without writing a dissertation, HALT is a type of qualitative accelerated test (vs quantitative) with the objective of discovering probable failure modes on the product during the design phase
For more details see http://www.weibull.com/AccelTestWeb/types_of_accelerated_tests.htm

For more details on Burn-in see
o How Long Should You Burn In a System? [HotWire Issue 69 (November 2006) (http://www.weibull.com/hotwire/issue69/relbasics69.htm)]
o How Long Should You Burn In a System? (Part II) [HotWire Issue 103 (September 2009) (http://www.weibull.com/hotwire/issue103/relbasics103.htm)]
o Sources of Reliability Data: Reliability Testing Basics [HotWire Issue 5 (July 2001) (http://weibull.com/hotwire/issue5/relbasics5.htm)]
o Bathtub Curve and Product Failure Behavior Part 1, The [HotWire Issue 21 (November 2002) (http://www.weibull.com/hotwire/issue21/hottopics21.htm)]
o Guidelines for Burn-in Justification and Burn-in Time Determination [Reliability Edge V7I2 (http://reliasoft.com/newsletter/v7i2/burn_in.htm)]
o Quantifying Optimum Burn-in Period [HotWire Issue 58 (December 2005) (http://www.weibull.com/hotwire/issue58/hottopics58.htm)]