[sdiy] Cyclone SID

[elmacaco]

You know I thought of SMT while I was building an x0xb0x kit (for info look
here http://www.ladyada.net/make/x0xb0x/ )

Which only had one SMT part for the USB port.  Hand soldering that wasn't
that bad, but looking at all the thru-hole leads piling up on my workspace I
got to thinking that parts using less metal, and above all less wasted metal
can be very good for the environment where copper and lead are mined as well
as overall efficiency.

Hand soldering SMT isn't something I want to sign up for, but hopefully
there will be ways to get your stuff machine done for cheap eventually.

if only they wouldn't use it to make disposable products that die in two
years causing more of this stuff in landfills. "look at your cell phone" ;)


----- Original Message -----
From: "Paul Schreiber" <synth1 at airmail.net>
To: "wayfar" <synth at wayfar.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, March 10, 2006 10:51 AM
Subject: Re: [sdiy] Cyclone SID


> >>
> > Ya but you have to admit the cost of assembly & part count adds up,
>
> Errr...not really. 'Adds up" for parts that cost $0.0004? Please!
>
> > you have a million parts, but where are you going to place them?
>
> Look in your cell phone :) I can place 144 0204 SMT parts in an area
> about 5mm x 5mm. Remember, 90% of SMT boards use *both sides*
> to place parts. Neary impossible with through-hole.
>
> > Pcb cost increases ect, you need more traces lines / could add up to a
> > multylayer pcbs where pricing skyrockets
>
> Errr...no. see cellphone above. In todays pcb technology, 6/6 rules are
> considered 'normal' (.006 lines with .006 spacing). This is due to the
> use of BGAs. In fact, if you use "fine pitch analog" traces of say 10/10
> the pcb board houses consider this to be "sloppy". In my MOTM modules
> most traces are 16mil or in a *few* tight cases 12mil. My pcb house
> giggles at my 'old tech' rules.
>
> > about masking and produciton errors / shorts ect testing is more
tedious.
> >
>
> Errr....no. All pc boards used in *production* (not etched in your sink)
> are 100% electrically tested *before stuffing* for opens and shorts. SMT
> pick-and-place machines, even mid-range ones, can put parts down on a pc
board
> within 0.005mm at the rate of 6-8 a *second*. There are no "errors" at
all!
> And, the beauty of SMT is there are virtually ZERO soldering defects.
> Wave soldering literally engulfs the entire bottom-side of the pc board
> in solder as it travels over the "wave" (a 'waterfall' is more like it)
and
> this is where solder shorts happen. In SMT, sold paste is only applied on
the
> pads of the parts. And it is placed VERY accurately.
>
> Paul S.