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| Reply To: | TechNet E-Mail Forum. |
| Date: | Wed, 13 Jun 2001 09:22:53 -0700 |
| Content-Type: | text/plain |
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Scott,
We've made pallets for this and there are two ways of thinking. Some prefer
to keep the bottom protected and thus insulate the bottom side components.
We've done this for years and it seems to work fine. Over the past couple of
years we have made them with holes in the bottom side so that the bottom
reflows also. The only complaint we have seen is that sometimes times parts
fall off the back and go into the converyor. I imagine this is a problem
that is rare if your process and machine are in good order. We have had some
people use our pallets for the sole purpose of keeping the parts from
falling into the machine. You can give me call off line if you'd like.
Jim Gleason
972-494-1911
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Jiang Ping
Sent: Tuesday, June 12, 2001 10:58 PM
To: [log in to unmask]
Subject: Re: [TN] Dual Side Reflow with A Pallet
Hi,
We have a similar board that double side reflow with a pallet. The pallet
actually is a frame with two beams. There are some support pins on the
beams that keep away from bottom components. When boards are put on the
pallet and clamped, the bottom side is not covered, so all the bottom side
solder joints are fully reflowed in the oven. It works very well.
Hope that helps.
Jiang Ping
----- Original Message -----
From: Lefebvre, Scott <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, June 13, 2001 6:26 AM
Subject: [TN] Dual Side Reflow with A Pallet
> I have an new assembly that is 14"x18" & .093 thick loaded with 16mil fine
pitch, BGA's and what ever else they could fit on the board. The bottom
side has chip resistors, caps, and 8 TQFP's.
>
> My question is I was thinking about putting the board in a pallet to
prevent warpage but I was concerned that the bottom side solder may be
effected during the Top side reflow. Normally bottom side components reach
liquidus and then cool back down. I was concerned using a pallet they
solder on the bottom side might stay just below liquidus and create a
plastic solder joint. I have used pallets in the past only on hybrids.
>
> Any help with this issue would be greatly appreciated!
>
> Scott Lefebvre
> Process Engineer
> ADC
> > F (530)265-1041
> > 8 (530)265-1012
> > * [log in to unmask]
> >
> >
> >
> >
> >
>
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Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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the BODY (NOT the subject field): SIGNOFF Technet
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Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
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