Yes, MIL-STD-202F is good testing condition  for bare PCB. But I  look
up IPC-TM-650 to find thermal cycling condition. It is as same as  MIL's
but qualification criteria is different. Which should I follow? Do you
think it is possibleto satisfy the requirement of FR-4 thermal shock
according to IPC-TM-650 if I use air to air chamber?

Howard Lin
Maxedge RD Center

> -----Original Message-----
> From: Werner Engelmaier [SMTP:[log in to unmask]]
> Sent: Wednesday, August 26, 1998 10:48 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] Thermal Cycling
>
> Hi Howard,
> It depends what it is you want to be doing. MIL-STD-202F thermal
> cycling was
> fine for hybrid assemblies or bare PCBs, but a disaster for SM
> assemblies,
> because it was outside the temperature ranges for near linear
> temperature-
> dependent property changes. For SM assemblies look at IPC-SM-785.
>
> Werner Engelmaier
> Engelmaier Associates, L.C.
> Electronic Packaging, Interconnection and Reliability Consulting
> 7 Jasmine Run
> Ormond Beach, FL  32174  USA
> Phone: 904-437-8747, Fax: 904-437-8737
> E-mail: [log in to unmask]
>
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