AVR-Chat

So, Tim, in my case I use solder paste, a pre-heater and a hot air nozzle
from a rework station.   Might it be safe to assume there is less of a
problem than with an oven?  Steve

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Tim Mitchell
Sent: Friday, March 15, 2013 9:18 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] moisture-sealed packaging

 

  

----Original Message----
From: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> 
[mailto:AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> ] On
Behalf Of Steven Hodge
Sent: 15 March 2013 16:02 To: AVR-Chat@yahoogroups.com
<mailto:AVR-Chat%40yahoogroups.com> 
Subject: [AVR-Chat] moisture-sealed packaging

> I realize this is off-AVR topic, but why the sudden(?)
> proliferation of putting parts in moisture-sealed
> packaging (e.g., by Digi-Key and Mouser), when they were
> previously not so packaged? Must the accompanying Threat
> of Dire Doom be taken seriously if limits are exceeded? 
> Why does it seem 
> limited to just SMT devices and not DIP?
> 

I'm not sure why they have suddenly started, but the reason it's done for
SMT not DIP is because of the oven soldering that is used with SMT devices -
they can explode/crack when put through the oven due to moisture boiling to
steam inside the device.

I have seen it happen quite a few times with LED's, but never with any other
devices.

The parts are sealed from the manufacturer, but once they open the pack and
start chopping a few off the reel, the reeled parts start absorbing
moisture. I can only assume they then re-seal the pack and remove all the
moist air, otherwise the packaging to the end user is pointless.

-- 
Tim Mitchell





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