Homebrew PCBs

I just got the Aoyue 968 about 2 weeks ago.  I don't have any experience with other units to 
compare to.  I am currently assembling my 995x board which has several several QFN 
package IC's, some ssop packages with .65 mm pin spacing, and an AD9954 with .5mm 
spacing.
  I used the temperature controlled soldering iron for most of it.  I bought the smallest tip they 
offered.  It is small enough I can solder individual pins on the 9954 under a microscope.  It is 
the first temp. controlled iron I've used and is very nice.
  I also ordered the vacuum pick-up attachment.  I tried it, but found that it would not release 
the part when I uncovered the hole on the side.  I had to knock the part off of the tool or turn 
off the vacuum.  This makes it pretty much useless for placing parts on the board.
  I used the hot air and solder paste on a smd oscillator and a QFN device.  With the air set at 
250 deg. C and the air flow just above minimum, it had no trouble melting the soldering 
paste.

Dave - WB6DHW
<http://wb6dhw.com>




[Non-text portions of this message have been removed]

I do not own this tool, but i have made my own vacuum pick from a
ball-point pen and a syringe needle.
From that i found too that making a hole in the side will indeed not
always release the components, since some residual vacuum pressure
seems hold them.

The solution:
push a piece of balled-up paper tissue into the handle, in front of
the hole, so it restricts the flow between hole and needle. This
introduces enough resistance so the parts are released cleanly. When
the hole is covered there will still be ample flow through the
high-tec calibrated paper tissue flow limiter.

I must admit i do not remember where i put the tissue, it is just
possible i put it behind the hole on the hose side. It would limit the
flow there too and might have a similar effect. Simply try around,
small pieces of paper tissue are relatively cheap, if you bulk buy and
cut them to size yourself ;-)

ST

On 8/24/07, brainerd@... <brainerd@...> wrote:
>   I just got the Aoyue 968 about 2 weeks ago.  I don't have any experience with other units to
> compare to.  I am currently assembling my 995x board which has several several QFN
> package IC's, some ssop packages with .65 mm pin spacing, and an AD9954 with .5mm
> spacing.
>   I used the temperature controlled soldering iron for most of it.  I bought the smallest tip they
> offered.  It is small enough I can solder individual pins on the 9954 under a microscope.  It is
> the first temp. controlled iron I've used and is very nice.
>   I also ordered the vacuum pick-up attachment.  I tried it, but found that it would not release
> the part when I uncovered the hole on the side.  I had to knock the part off of the tool or turn
> off the vacuum.  This makes it pretty much useless for placing parts on the board.
>   I used the hot air and solder paste on a smd oscillator and a QFN device.  With the air set at
> 250 deg. C and the air flow just above minimum, it had no trouble melting the soldering
> paste.
>
> Dave - WB6DHW
> <http://wb6dhw.com>
>
>

>When the hole is covered there will still be ample flow through the
>high-tec calibrated paper tissue flow limiter.

This approach for a fixed vacuum setup or simply reducing the vacuum, 
where adjustable, limits you in terms of the size/weight range of 
components that can be handled without having to fiddle with the 
settings. With it setup to release 0402 - 1206 components cleanly, for 
example, you're going to find that the vacuum might not be enough to 
handle heavier ICs without dropping them.

A "finger" toggle switch on the pen or a foot toggle switch that 
directly or indirectly controls the pump (on/off) is the best way to 
go. That way the vacuum can be set to handle the heaviest components 
without dropping and still release the lightest cleanly. Basically, 
that's the way an automatic pick & place machine works with the switch 
under software control. Manual ones typically use a foot switch. At 
least mine does.


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>

On 8/30/07, derekhawkins <eldata@...> wrote:

> With it setup to release 0402 - 1206 components cleanly, for
> example, you're going to find that the vacuum might not be enough to
> handle heavier ICs without dropping them.

_might_ ....

still worth a try, takes about one minute and it _might_ work.
The alternative might also work (will if correctly done, but there
might be mistakes made), and takes rather long.

ST