Subject: | |
From: | "Jeff Seeger" <simon.ipc.org!bort.mv.net!rapidcad!jseeger> |
Date: | Sat, 15 Jun 96 01:22:24 EDT |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hello, Technet!
I'm looking for empirical advice on thermal relief sizing. The
IPC 275 answer is a maximum copper attach of .160 or .080 (1 or 2
oz cu), fine for loads but not sufficient for the supply side.
The application is a pressfit backplane with an intended (oof)
fountain soldered power connector. Problem with power connectors
of late is that we're up to 10 amperes/pin, or to put it another
way, ~twice the max recommended thermal connection.
On these particular backplanes there are also reflowed discrete
components. None of the manufacturers we're working with are
using intrusive reflow yet. (hint, hint?)
Is anyone having repeatable success using any other guideline?
The IPC 275 answer does not mention specific soldering process
but would presumably cover wave. Will long-and-slow fountain
techniques suffice? To make matters worse, not every pin on the
connector has so much load (or copper).
My guess is we're stuck with hand solder or at best messy touchup.
Best Regards,
Jeff Seeger Applied CAD Knowledge Inc
Chief Technical Officer Tyngsboro, MA 01879
[log in to unmask] 508 649 9800
Anybody remember when boards were flat, green, and nothing could
touch?
|
|
|