We have a couple of CCA's that are about the same thickness as you mention.
The main problem seemsthe heat that is drawn away by the ground plane.  We
have found the best way to wave them is to pre-heat them before ever
putting them in the vwave solder machine.  We soak the boards in our vacuum
oven for a minimum of 1 hour at a temp of 100 C.  This allow the entire
board, including the ground plane, to start the solder process with an
elevated tempurature.  I have found that this allows the wave profile to be
similar to other boards in that I can maintain a fairly quick conveyor
speed.  As far as rework is concerned, this is the only way I know to
reework the boards.  We use the oven extensively to pre-heat cards prior to
rework.

Bruce Stilmack
GDLS-TO Manufacturing Engineer
(850) 574-4773
[log in to unmask]



                      "Karnwal, Pankaj"
                      <Pankaj.Karnwal@B        To:       [log in to unmask]
                      ARCO.COM>                cc:
                      Sent by: TechNet         Subject:  [TN] Vertical fill up of 3.2mm thick PCB.
                      <[log in to unmask]>


                      08/16/2004 02:24
                      AM
                      Please respond to
                      TechNet E-Mail
                      Forum; Please
                      respond to
                      "Karnwal, Pankaj"






Dear Tecnetters " Hi "

we have a PCB of 12 layers with thickness of  3.2mm.

Problems we are facing are

1.Solder doesn't come top side and as the thickness is more than pre
established components lead lengths ,like DIP's  IC,connectors pins , it is
mandatory for us that a fully wetted solder is visible from primary side.

2.Many of the components are on the ground plane , so if any rework is
required we could not do so by soldering iron ( we tried weller 150 watts
iron with temp. 450 deg. C , but we could not remove an electrolytic cap.)

3.What IPC tells about the power connector lead protrusion and the top side
solder fill up for the same. As the IPC 610B states in components
installation 3.5.3.1/note: that lead protrusion may not be visible in more
than 2.3mm thick boards.How we interrelate it with soldering 4.1/vertical
fill of soldering 75 % in this case.

4.We are using AC by pass connector  "PICH47F400A1" with recommended PCB
hole dia 2.1mm for lead dia 1.6mm , Is it enough for 3.2mm thick PCB too.


Any body have the soldering experience of 3.2mm thickness PCB. what
parameters ( wave height/ pre heater temp ) of wave soldering M/c matter in
this case .Is chip wave is useful , Pls. share your exp. it will be highly
appreciated.

Thanks

BR
Pankaj Karnwal
Jr. Engineer QA

Barco Electronics System  (P) Ltd.
Plot no. A- 4 & 5, Sector- 5
G.B Nagar, Noida  - 201301
India
Tel .+91-120-2421651-660 Ext.211
Fax.+91-120-2421691
WWW.barco.com
mailto:[log in to unmask]


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