[sdiy] SMD comming your way

[Sten Björnebro]

On Sat, 28 May 2005 23:33:36 +0200 (CEST)
Magnus Danielson <cfmd at bredband.net> wrote:

> Hi SMD-lovers!
Hi i lowe them.

> 
> OK, so we fooled around in the lab yesterday. Actually, I didn't do much than
> comming with encouragement!
> 
> Anyway, here you find a few SMD components stacked:
> http://ebs.homedns.org/bilder/komponents/komp33/pict2805_Lg.jpg.42.html
> 
> We have these stacks:
> 2412 1210 1206 0805 0603 0402 0201 01005
> 
> All are resistors except the 0201 which is a capacitor.
> 
> Then we have:
> 
> http://ebs.homedns.org/bilder/komponents/komp33/pict2778_Lg.jpg.16.html
> 
> Here you see the size of a 01005 well explained, it is quite visibly sloping
> due to the height-difference between the gold-plated pads and the green lacquer
> covering the PCB. Actually, there is a clearence around the pad where the
> lacquer is much thinner.
> 
> Here it is soldered in:
> http://ebs.homedns.org/bilder/komponents/komp33/pict2779_Lg.jpg.17.html
> 
> Here is another example:
> http://ebs.homedns.org/bilder/komponents/komp33/pict2765_Lg.jpg.3.html
> and soldered in:
> http://ebs.homedns.org/bilder/komponents/komp33/pict2770_Lg.jpg.8.html
> 
> Oh, the pads on there I beleive is as far as 1 mm apart centrum-to-centrum
> distance.
> 
> Well, it didn't take too much time for a pro to solder them 01005, but he
> think he need to exercise some more. Maybe the 0,23 mm solder wire is a bit to
> thick...
> 
> Also, all of a sudden electrostatics comes into play. It doesn't help just to
> keep an ESD environment, but we might need to keep tools grounded as well.

I felt it was the resistor that had been charged whith static.
My two twezer was antistatic and my desk an the shoes and even the chair.
So it has to bee the resistor that had to bee taken out from the tape on the wheel.
The resistor whas from koa.

Magnus cold you calculate the force on the resistor compared to columb or voltage?
1000pcs weight 0.03g "gram"  !..
Here is the reference.
http://www.koaproducts.com/english/catalogue/012-013-RK73B.htm

> 
> Also, the tweezers not only need to be grounded, they need to be really clean.
> Any residue solder resin make the 01005 stick with the tweezer, so they have to
> be cleaned with suitable alcohol to be bare metal, but that works. However, in
> any real lab that stuff is just a short stretch away anyway.
> 
> OK, so with some minor exercise will the 01005 be handsoldered, or at least by
> someone already doing 0402 on a daily basis, which is also possible I might
> add.
In standard mobile telefone there are 0201 to day so when you to repair yor celluar 
in future ther whold bee 01005 in it.

> 
> Cheers,
> Magnus - keeping the notes behind the masters back


//Sten Björnebro. -=|***----------------------------------------
// Soldering addicts.