Soldering SMD's

[cyborg_0 at iquest.net]

You dont even need the magnifying glasses if you are very nearsighted.. I can see things that 
the microscope prlly cant resolve! ;)

No-clean flux, jewelers tweezers, dentist picks, braid, normal ol 15watt radio shack iron with 
a filed-down tip (yes, and i have no probs whatsoever) multicore no-clean flux, and a light 
magnifier. 

This is all I use.

Using these items and nothing more fancy, I have put together hundreds of boards, some with 
very fine hairlike leads and have had no problem.. But, expect problems when you first start 
out.

Its definitely more of an art, and you will soon learn with the no clean there is a very short 
time between having flux and having the solder ball up and none end up on the joint. 
The no-clean solder that I use is alchohol based, so you only have a brief time to work with 
it.

One of the key mistakes I see ppl make is to solder a part down only to find that the very 
small resistor has some solder than didnt take completely and there is a crack in the joint or a 
very fine smd chip lead that LOOKS nice and shiny and soldered but actually has NO solder 
on the pad, thereby producing an intermittent connection. Usually, too, this has to do with the 
evaporative nature of the flux.

Theres about a 5 second window where you MUST get that lead soldered or forget it 
because you will overheat the part. There a few other techniques too, like using a preheat pan  
for your parts so you dont shock them too badly (esp a prob for ceramic parts, like caps) but 
the preheat pan can merely be your oven for a few hours at 200 F.


Rob



> ** Original Subject: RE: Soldering SMD's
> ** Original Sender: Tim Ressel <Tim_R1 at verifone.com>
> ** Original Date: 14 Apr 2000 15:35:09 -0000

> ** Original Message follows... 

>
> Jaakko,
> 
> This is a skill I recently picked up. Here is my take on the equipment needed:
> 
> 1. Soldering iron. Must have really small tip for SMT work. 
> 2. Really small solder helps alot.
> 3. Tweezers. Really small ones made for SMT work. This is a must.
> 4. Use no-clean solder and have a bottle of no-clean flux handy.
> 5. Optics. The only way to see solder shorts and solder balls is
>    with optics. I am lucky to have access to good microscopes made
>    for this purpose. I suppose you could use a *good* magnifying
>    glass. Use good lighting, too.
> 
> 
> Tim Ressel--Compliance Engineer
> Hewlett-Packard
> Verifone Division
> 916-630-2541  
> tim_r1 at verifone.com                     
> 
> 
> 
> -----Original Message-----From: Jaakko Lofstrom [mailto:jlofstro at pcu.helsinki.fi]
> Sent: Friday, April 14, 2000 5:24 AM
> To: synth-diy
> Subject: Soldering SMD's
> 
> 
> While we're on the subject ( well actually on the absolute opposite of it
> but that's ultimately the same, isn't it.. ) of soldering, I'd like to ask
> something that's been buggering me for a while:
> 
> What's the minimum configuration needed to solder SMD's?
> How do you do it?
> I mean do you need special soldering tips or stuff or is it possible to
> use a hot air blower in a wave-soldering fashion? As you can see, I'm
> totally lost with the subject ;)
> 
> -- 
> -jaakko löfström
> ...............................................................................
> ..........,....................................................................
> ...............................................................................
> If you stare at the random dots above long enough, you'll see a SPECTACULAR 
> IMAGE OF A LAKE WITH TWO SWANS AND A BUNCH OF SILLY GNOMES 
IN FULL COLOUR 3D!
>  
> 
> 


>** --------- End Original Message ----------- **

> 



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