AVR-Chat

We often use a similar technique but we've found that you often don't need the extra solder. There's usually enough on the board plating to complete the connection (unless you're doing gold boards).  Use lots of flux.

We've also found that water soluble flux works the best, just be certain to clean it all off!!  Really weird things happen if you don't; also many water soluble fluxes contain acid.  We'll often clean with just a bit of Simple Green to neutralize the acid and get the boards really clean.


Tim Gilbert
JEM Innovation Inc.
303-926-9053 (office)
303-437-4342 (cell)
720-890-8582 (fax)
www.jeminnovation.com
www.pdksolutions.com


  ----- Original Message ----- 
  From: Brian 
  To: AVR-Chat@yahoogroups.com 
  Sent: Wednesday, June 27, 2007 4:54 PM
  Subject: [AVR-Chat] Re: Placing and soldering SMD parts for prototypes - OT?


  I do this stuff everyday at work. It even works on QFP100 and bigger 
  with 10mil pitch. Place your part on the board, hold the center down 
  with your finger. Place flux at four spots, one on each side and 
  touch with a clean iron to tack and hold it there. next, flux all for 
  sides with liquid (water soluble flux), place a small amount of 
  solder on the tip of your iron and using the weight of your iron ONLY 
  (do not put any extra pressure or you will bend pins) and drag from 
  one side to the other. if done right you can, or I can, solder the 
  whole thing in 15 seconds.

  --- In AVR-Chat@yahoogroups.com, "Richard Cooke" <rcooke@...> wrote:
  >
  > Hi Folks,
  > 
  > Up until today, I've been fairly successful in soldering SMD parts 
  for
  > my prototypes but it looks like I've got a short in one of the QFN32
  > parts. How do you place them? I guess my hand shook a bit when I 
  was
  > placing the thing and now one of the Vcc pads are shorted to a GND 
  pin.
  > 
  > I've managed to get the 0603 parts down without much problem but 
  this
  > QFN32 part is tough. I've placed the ATMEGA48 (TQFP package) and it
  > soldered fine.
  > 
  > I'm looking for some suggestions/words of wisdom on what other folks
  > do for their prototypes.
  > 
  > Thanks,
  > 
  > Richard Cooke
  >



   

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