David and Guenter,
Let me add my $ 0.02 worth...
Not to confuse things, but according to the JEDEC Test Method, JESD22-A104-A
Temperature Cycling, in Section 3.1 Timing:
The total transfer time from hot to cold or from cold to hot shall not
exceed 1 minute. The load may be transferred when the worst case load
temperature is within the limits specified in Table 1 - Temperature Cycling
Test Conditions. However, the dwell time shall not be less than 10 minutes,
and the load shall reach the specified temperature within 15 minutes.
MIL-STD 883E, Test Method 1010.7 Temperature Cycling, reads the same as the
JEDEC Test Method. My interpretation is that as long as the assembly being
tested reaches the specified temperature within 15 minutes of transfer from
one temperature extreme to another, then the test is valid.
Of course, if you really want to stress the hardware, you may want to
consider using the JEDEC Test Method, JESD22-A106-A Thermal Shock, in
Section 3.1 Timing:
The total transfer time from hot to cold or from cold to hot shall not
exceed 10 seconds. The load may be transferred when the worst case load
temperature is within the limits specified in Table 1 - Thermal Shock
Temperature Tolerances and Suggested Fluids. However, the dwell time shall
not be less than 2 minutes, and the load shall reach the specified
temperature within 5 minutes.
MIL-STD 883E, Test Method 1011.9 Thermal Shock, reads the same as the JEDEC
Test Method.
Hope this clears up any confusion.
Good Luck.
Lee Whiteman
Senior Manufacturing Engineer
ACI / EMPF
Telephone: (610) 362-1200; Ext. 208
FAX: (610) 362-1290
E-Mail: [log in to unmask] <mailto:[log in to unmask]>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of David Fish
> Sent: Wednesday, November 29, 2000 7:10 AM
> To: [log in to unmask]
> Subject: Re: [TN] Antw: [TN] Temperature Cycle to product life
>
>
> Guenter: Should the rate of temperature decrease be the same as
> the rate of temperature increase that you quote? Dave Fish
>
> Guenter Grossmann wrote:
>
> > David
> >
> > This translates to nothing because:
> > - We don't know the temperature swing in your application.
> > - 5 min. dwell time at -55 degC is as much as nothing, thus no
> strain is induced.
> > - 10 degC / min is very fast below 20 degC and you are very
> likely to activate degradation mechanisms that do not occur in reality.
> >
> > Running a test
> > - 0 / 120 degC
> > - 4 degC / min up to 20 degC
> > - 10 degC / min above 20 degC
> > - dwell time of 5 min at 120 degC
> > - dwell time 30 min at 0 degC
> >
> > would give in my opinion the possibility for a rough estimate
> of the lifetime in a realtime environment by
> >
> > Nfr = Nft ( dTt / dTr )exp1.7
> >
> > Nfr = Number of cycles to failure reality
> > Nft = Number of cycles to failure test
> > dTr = Temperature swing reality
> > dTt = Temperature swing test
> >
> > Best regards
> >
> > Guenter
> >
> > Guenter Grossmann
> > Swiss Federal Institute for Materials Testing and Research EMPA
> > Centre for Reliability
> > 8600 Duebendorf
> > Switzerland
> >
> > Phone: xx41 1 823 4279
> > Fax : xx41 1823 4054
> > mail: [log in to unmask]
> >
> >
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