AVR-Chat

I use the same process with no-clean liquid flux, works very well.
Solder paste + toaster oven also works amazingly well if your doing
many SMD components.

The method described has also worked well for me on 5mm*5mm QFN
package chips without any problems.

Knowing the process is good, but nothing beats practice !!!!

Cheers
Hein B
Auckland, New Zealand.


--- In AVR-Chat@yahoogroups.com, "Tim Gilbert" <tim@...> wrote:
>
> 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
>   >
> 
> 
> 
>    
> 
> [Non-text portions of this message have been removed]
>