Steve
Before you spend money on 45 degree fixtures, you might want to try getting a fixture that allows you to run the board on any angle. I've got one, and have run some extensive experiments with it. What I found is this: 45 degrees was better, but 40 degrees was best for one board and about 12 degrees was best for the other beast I'm running.
My interpretation of that is that the layout will affect the flow, and so no two boards will be the same. The down side is that you have as many possible angles to try as you want. I arbitrarily decided to only go through a 90 degree range (otherwise you will need hundreds of boards to try)
Good luck!
regards
Graham Collins
Process Engineer, Litton Systems Canada, Atlantic Facility
(902) 873-2000 ext 6215
>>> [log in to unmask] 10/03/00 05:51PM >>>
Hey everybody!!
Remember about a week ago I posted about a little mixed technology board
(actives on the top, passives on the bottom) that we do here that is laid-out
pretty bad as far as wave soldering goes, and we have all this touch-up that
we have to do after wave?
Well there's hope. Ed Popielarski suggested something to me that I didn't
think of. It was using a fixture that oriented the board 45° to the wave...he
was able to get one for me to try just to see if it made anything
better...and boy did it!!
Go to:
http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures
You'll see two pictures there, one is: With45.jpg, and the other is:
without45.jpg...let me tell you, the Without45.jpg is pretty ugly. I still
did have a few defects with the 45° orientation, but nowhere NEAR like I was
having before. Most of the defects are with them pesky SOT-23's, and because
of the layout, I think there's always going to be some touch-up...
I'm gonna be getting some dedicated 45° fixtures made for these guys, and
just maybe be able to tweak things even better!
Thanks Ed!!
-Steve Gregory-
> Hi ya'll!!
>
> I wished this little beast lent itself to a selective wave soldering
pallet,
> but it don't. Go to: http://www.driveway.com/share?sid=e25a88c4.8e904&name=
> Pic
> tures
> and look at "Funwave.JPG" to see what I mean.
>
> You can see by the dime I put there how big it is. This comes in a 10-up
> panel. There's about a dozen SOT's, eleven-1206's, and around thirty-0805's
> on the backside. Up top there's three-14-pin, one 8-pin, and one 6-pin DIP
> IC. There's also one 5-pin right angle header, as well as two radial caps,
> one axial fuse, and a 3-pin PTH transistor.
>
> The 14-pin straddle mount connector and the two LED's have to be hand
> soldered because they also straddle the board. The variable resistor on the
> backside also is hand soldered because it can't be waved...fun stuff huh?
>
> We do get skips...mostly on the SOT's that I've seen...Mike said he's seen
> some on the other passives as well. We do get other defects because of the
> layout of things on the bottom. Those two 1206 caps in the upper right
> corner
> bridge quite a bit, and there's always the excess solder on the leading
edge
> of a component that's oriented the wrong way to the direction of travel in
> the wave.
>
> Me and Mike have been discussing this wonderfully designed board. My
opinion
> is that using paste and adhesive may take care of some of the problems, but
> with this board there's always going to be touch-up.
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