Hi Tom - well, nothing beats the real board but we often have the same
issue. You have a couple of options that have been shown to get you in the
right ball park: (1) there is profile software that does a pretty
reasonable job of getting a valid thermal profile which you then tweak as
you run your first couple of boards; (2) If you add these factors together:
board thickness, total amount of copper weight, component technology type
and component density - you should be able to create an initial working
thermal profile. I put together a set of "golden" boards reflecting these
variables many moons ago, thermal coupled them and recorded their profiles.
That action provided me a thermal profile comparison window I could then
use to estimate what a new design might demand for thermal inputs. Over
time, we have gained enough comparison experience that we can created a
thermal profile for a new design that is fairly accurate and only needs
small tweaks.

Dave Hillman
Rockwell Collins
[log in to unmask]

On Thu, Feb 4, 2016 at 4:49 PM, Tom Gervascio <[log in to unmask]>
wrote:

> Many times we have to create an oven profile but only have a bare board.
> Many times the boards are complex and have many bottom terminated
> components on them and wanted to avoid having to guestimate how a profile
> for a bare board would actually perform on a populated board. Can't imagine
> that we are the only persons to face this problem. Wondered how other users
> have worked around this problem?
>


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________