Tom;
 
     There are several systems out in the market that vary widely in the bells 
and whistles you want. Prices also vary just as widely ($5k - $70K) depending on 
what you want out of a system. Motorola recommends using a hot air system that 
is top-heat only. We have found that systems with localized bottom heating also, 
warp boards. 

     The key is to have a top heating system, but preheat the entire board to 
avoid board warpage. This top heating system should have a high wattage heater 
in order to work at low temperatures with a low velocity air flow, to prevent 
blowing away neighboring components. And, IMHO, it should be simple to use.

Please feel free to eMail me if you want specific information on Metcal's 
solution to this issue.
     
     Tom Lee
     Applications Solutions Group
     Metcal, Inc.

     [log in to unmask]

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> From: [log in to unmask] (Tom Stangler)
> Newsgroups: alt.electronics.manufacture.circuitboard 
> Subject: BGA rework
> Date: 16 Nov 1995 23:31:56 GMT
> Organization: InfiNet
> Lines: 10
> Message-ID: <[log in to unmask]> 
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> 
> I'd be interested in hearing how others have performed BGA chip 
> rework on populated boards. hot air? IR? conduction?
> 
> --
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