Calculating MTBF (Mean Time Between Failures) of different Electronic Components. [Elsmar Cove Index (Ar)]


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Sherin MR

20th February 2008, 02:02 AM

harry

20th February 2008, 03:19 AM

Welcome Sherin,

First, you must titled your thread appropriately. The moment MTBF appears in your title (I edited it), the software will lead you to similar threads found in the 'similar discussion threads box' below your post. These will lead you to other relevant threads without the need to do a search.

A good reference is MIL-HDBK-217F. (http://elsmar.com/pdf_files/Military%20Standards/MIL%20HDBK%20217F.pdf)

Mean_time_between_failures is also a good resource for this topic.

MTBF Calculation Tutorial (http://mtbf.polimore.com/index.php?Filename=help.1.1.en.php&LANGUAGE=en)

Online Reliability calculator (http://www.pixelbeat.org/docs/reliability_calculator/)

Sherin MR

20th February 2008, 03:33 AM

Hi
Am sorry.
I have visited this sites before (WIKI,MTBF Calculation tutorial).
But there are no guidelines to use it.
Can u please give me some information from where i can get it.

Regards
Sherin.

harry

20th February 2008, 03:45 AM

Have you done a search here?

Have you gone through this thread? Calculating MTBF for an electrical component (http://elsmar.com/Forums/showthread.php?t=16578)

harry

20th February 2008, 03:51 AM

Hi
Am sorry.
I have visited this sites before (WIKI,MTBF Calculation tutorial).
But there are no guidelines to use it.
Can u please give me some information from where i can get it.

Regards
Sherin.

I am not sure what you meant by it. Do you mean that you do not have basic data or understanding of this concept? Or you may want to try a google search. (http://www.google.com/search?q=how+to+calculate+mtbf&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enMY235MY235)

Otherwise look at MIL-HDBK-217F. (link provided in post #2)

Sherin MR

20th February 2008, 05:43 AM

Hi
I meant that i dont know how to use this MTBF calculator.
There are no guidelines shown how to use this MTBF calculator.
Regards
Sherin

w_grunfeld

21st February 2008, 05:41 AM

Hi
I meant that i dont know how to use this MTBF calculator.
There are no guidelines shown how to use this MTBF calculator.
Regards
Sherin
In principle all prediction methods are the same: you start off with a basic generic base FR per part type and then you have to multiply it by a series of Pi's (coefficients) for environment, temperature, voltage, stress, quality level and so on..... depending on each type of component. The methodology is spelled out in MIL-HDBK-217 ...it's hundreds of pages...You can't expect the formula for each component to be posted in a forum...

By the way MIL-HDBK-217 is obsolete, replaced by 217 Plus, plus others like Telecordia.
No one uses manual methods anyway....Get yourself a computerized tool unless you have to calculate for 3-4 components...
Willy

Sherin MR

21st February 2008, 06:49 AM

Hi
I went thru the MIL-HDBK and found different parameter like
*base failure rate
*temperature factor
*power factor
*power stress factor
*quality factor
*environment factor
*capacitance factor
*voltage stress factor
*series resistance factor
Can anyone say from where I could get more information about this factors?
I searched in GOOGLE but didnot get any information that I require.
Please anyone respond to this.
Regards
Sherin.

w_grunfeld

22nd February 2008, 08:23 AM

In the mil-hdbk itself. Go to the respective part type section, and each has tables with the values for each factor that is applicable to the respective part type. (noyt all factors are applicable for all part types!)

Sherin MR

5th March 2008, 12:32 AM

Hi
Is the MIL-HDBK-217F (Military Handbook) based on shortcircuit or opencircuit failure?
Does the values(like Base failure rate,Temperature factor,Power factor,Power stress factor,Environment factor,Quality factor) provided for different electronic components are based on short circuit failure or open circuit failure?
Waiting for the reply.........

Regards
Sherin.

w_grunfeld

5th March 2008, 08:20 AM

In 217 a failure is any failure , i.e. no separation into the various failure modes. Short , open are not the only possible failure modes for many component types....

Al Rosen

5th March 2008, 11:08 AM

Hi,
Can anyone please guide me in calculating MTBF of different electronic components.What are the parameters required for calculating the MTBF?
Can anyone please respond to this as it is quite urgent.........

Regards,
Sherin MR.

Try this calculator for components based on MIL-HDBK-217.
Reliability - Military Handbook MIL-HDBK-217 (BETA) (http://www.sqconline.com/reliability/index.html)

Sherin MR

12th March 2008, 01:26 AM

Hi
Can this MIL-HDBK-217F be used for calculating the FIT and MTBF of commercial components?Waiting for a reply......

Regards,
Sherin MR.

w_grunfeld

12th March 2008, 08:18 AM

Yes for MTBF of commercial components, but results will be biased (overly pessimistic) better use Belcore for commercial
FIT is another order of magnitude , failures in 10**9 hours, it's for IC's and you should get the data from the manufacturer not estimate it by any of the standards based methods. Manufacturer's derive the FIT from life test data , not predictions!

Sherin MR

20th March 2008, 06:42 AM

Hi,
Could anyone help me in downloading the SN29500 standard?I have searched in Google but was not able to download it.Could you please give me the link for downloading this standard.Waiting for you reply.................................

Regards,
Sherin MR.

Sherin MR

15th May 2008, 03:31 AM

Hi,
Actually how MTBF is calculated?
Is it MTNF=MTTR+MTTF
Where MTTR=1/REPAIR RATE
MTTF=1/FAILURE RATE(Lambda)
or
MTBF= 1/FAILURE RATE
Where failure rate is calculated using prediction standard (for example SN29500)

Can anyone help me....
Waiting for ur reply
Regards,
Sherin MR

w_grunfeld

18th May 2008, 08:43 AM