Steve,
Both Indium SMQ92 and Aim 293+ will not slump at all. (I actually
measured a negative slump, but the amount was within experimental error).
I'm sure there are others, but the slumpers certainly out number the
non-slumpers.
Thanks
Ryan Grant
Advanced Technology Engineer
MCMS
(208) 898-1145
[log in to unmask]
> -----Original Message-----
> From: Ron Waugh [SMTP:[log in to unmask]]
> Sent: Tuesday, September 26, 2000 2:48 PM
> To: [log in to unmask]
> Subject: Re: [TN] Wave soldering bottom SMT, here be the "Jewel"...
>
> Steve,
>
> I have not done the solder analysis on this solder paste yet, but have a
> lot of
> documentation on AlphaMetals new Omnix paste "OM - 5000". It is a
> No-Clean
> paste that is guaranteed not to hot slump....."supposedly the only one on
> the
> market...so far". This may help you in your endeavor to paste and
> dispense,
> without the defects of your previous experience. Hope this helps!
>
> Regards,
>
> Ron Waugh
>
>
>
> ______________________________ Reply Separator
> _________________________________
> Subject: [TN] Wave soldering bottom SMT, here be the "Jewel"...
> Author: "TechNet E-Mail Forum." <[log in to unmask]> [log in to unmask] at
> Internet-gateway
> Date: 9/26/00 2:43 PM
>
>
> 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.
>
> I also ask myself what new problems might be introduced dispensing
> adhesive.
> The last "good" dispenser I've used was a FUJI FGL-V...and back then we
> did
> have some issues with epoxy bleeding on to the pads with SOT's as well as
> the
> "tail's" stringing onto the pads when things weren't working as well as
> planned...
>
> One last issue we talked about was an experience I had at a past company
> where we printed paste and dispensed adhesive. What would happen during
> reflow was when the paste would hot slump, some of the paste would embed
> itself into the epoxy, and then cure...so we had all these little
> solderballs
> cured into the epoxy. Our customer wouldn't take the boards like that, and
> we
> wound-up eating them...
>
> -Steve Gregory-
>
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