Lpc2000

David Hawkins wrote:

>Ok, so it seems I'm not the only one concerned with BGA
>prototyping or 'hobbiest' use of such devices.
>
>What kind of expense have people experienced for board
>manufacturing?
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>I have used subcontractors to load boards with *LOTS* of
>BGA devices, and if I recall correctly, there was a $3k
>NRE charge to setup the reflow machines. We had a bad
>FPGA on one board, and that same company was able to
>remove and replace the BGA using a hot air gun. A
>pretty impressive feat - given that there were lots of
>FPGAs around the one they removed (it was a correlator
>board)
>
>http://www.ovro.caltech.edu/~dwh/correlator
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>How about the guys reading this list that have played with
>homemade reflow machines based on quartz ovens - any attempts
>at loading BGA devices? Any success?
>
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I'd be intereested in that answer myself.  I've had excellent results 
using a quartz 1500W toaster oven + mylar stencils for the LPC2xxx 
processors and other fine pitch packages.  I'm not sure how successful I 
could be with BGA though.  From what I hear, placement of the device is 
very critical and difficult to do.  Aside from that, I suspect (nobody 
will confirm this) that a hot "gas" is needed to push heat under the 
carrier.

 From what I've been told, large scale operations use a hot nitrogen gas 
to reflow such boards.  I know of the hot air unit you are referring 
to.  AFAIK, those units are pushing 700..900F hot air flow.  
Temperatures not possible in a quartz (IR) oven.

TomW


>Dave
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>Yahoo! Groups Links
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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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