[Coco] Surface Mount Soldering

[jdaggett at gate.net]

Lots of flux and fiduciles on the board for the corners. 

I used to solder 80 pin BGA packages with 30 mil balls. The pitch was 0.1 inch if I remember 
correctly

Seat the part and then place on a hot hotplate. As the solder melts, the package drops and 
about 30 seconds later slide the board off the hotplate. 

Did this to many a MC68HC11PH8 in an 80 pin BGA package. Not one failed in an 
accellerate life test. All survived the temperature cycling of -40degrees C to +85 degrees C. 
The parts went from one chamber to the other in less than 30 secondes. 

I found most of the hot air reworks do as much heating if not more than the hotplate. If the air 
pressure is set to high then the chance of disturbing other parts close by increases. 

With the hotplate if you do make a mistake it is usually the whole board needs repair. So care 
is needed in both assembly process. It also helped to have some 3 inch square ceraminc 
plates that were about 60 mils thick. I placed one on the hotplate and used another to receive 
the board as I slid it onto the cold ceramic plate. I still have about 15 or so of the alumina 
ceramic plates. Make nice wetstones to sharpen knife baldes also.  

james 

On 6 Jul 2010 at 15:51, Mark Marlette wrote:

> james,
> 
> How does one manually locate/align(x/y/z/theta,down force) of a BGA on to the pads using a hotplate?
> 
> I use our Air-Vac DRS25 unit and I am spoiled with it.
> 
> Mark
> Cloud-9
> 
> 
> ----- Original Message -----
> From: jdaggett at gate.net
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Tue, 06 Jul 2010 13:57:08 -0000 (UTC)
> Subject: Re: [Coco] Surface Mount Soldering
> 
> The key to using a soldering iron for SMT work is having enough flux on the board and not to 
> much solder. 
> 
> There are other alternatives to the soldering iron approach. 
> 
> One is a hot plate. A 4in square hotplate by Thermalake is very good alternative.
> 
> Second is the few toaster oven reflow boards out there. The stand alone controllers range in 
> the $60 to $100 and then add what ever your local Walmart or Taget has in a 1500 watt 
> toaster oven. 
> 
> The lone issue with the toaster oven is that it should have burners on the top and bottom and 
> a circulating fan inside to reduce hot zones. ALso the toaster oven method needs to work at 
> max temperature to melt the newer lead free solders. Also the different preheat times will 
> need adjusting.
> 
> I still like the hotplate for small boards. especially with BGA packages. 
> 
> james
> 
> On 6 Jul 2010 at 0:30, Aaron Wolfe wrote:
> 
> > On Mon, Jul 5, 2010 at 9:39 PM, Little John (GIMEchip.com)
> > <sales at gimechip.com> wrote:
> > > This guy has some amazing videos on SMT soldering - I never get bored just watching these. Some have sound, some are silent, but they are beatiful nonetheless :-)
> > > http://www.youtube.com/watch?v=wQXhny3R7lk
> > > This is the vertical drag technique that my dad uses too.
> > > -John
> > > P.S. check out all of this guys videos if you have time. They are amazing.
> > > -Lil' J
> > >
> > 
> > That is interesting to watch.  I recently got a ham license and have
> > been soldering together some very simple circuits to reduce
> > interference when connecting a radio to an PC to decode digital
> > modes.. anyway, boy am I bad at soldering!  That guy is like the
> > maestro of solder.
> > 
> > There are a lot of good "how to" videos on youtube for all kinds of
> > things, if you're in to do-it-yourself, its a great resource.
> > 
> > 
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> > >
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