Hi All
Thanks for your Reponses
I will try all your suggestions in next lot and post the results , as I had
only four board that I have already used with bad results.
Regards
Pankaj
> -----Original Message-----
> From: [log in to unmask] [SMTP:[log in to unmask]]
> Sent: Monday, August 16, 2004 8:46 PM
> To: [log in to unmask]; [log in to unmask]
> Subject: Re: [TN] Vertical fill up of 3.2mm thick PCB.
>
> Hi Pankaj!
>
> I have a board like that here that we build, and at first it gave me the
> same problems you face.
>
> This might sound out of the ordinary, but you do what you have to do when
> you are faced with a board that is unusually thick and has heavy copper
> planes in it. I run the assembly twice through my wave machine. Once with
> the wave pumps off to pre-heat it, then once again with the pumps on. You
> could accomplish the same thing by pre-heating the board in a oven, but I
> don't have a oven close by my wave machine, so I use the wave pre-heaters
> instead.
>
> I also flux the topside of the board manually to help aid heat transfer a
> little, and it seems to improve capillary action too. I also use both the
> rotary and laminar wave pumps.
>
> I have a Electrovert Electra machine with a Optiflux-1 spray fluxer. The
> machine has three bottomside convection pre-heaters. I run my beltspeed at
> 3.5 feet per minute, and my pre-heaters are set at 270 F., 280 F., and 300
> F. going from the entrance to the solderpot. I use a Alpha 615-25 RMA
> flux. I leave the fluxer on for both passes through the machine.
>
> I use a fixture for the board that has solder dams around all four sides,
> so I can run the board quite a bit deeper in the wave than normal.
>
> As far as rework on the board I use a system from Zephrytronics (
> <http://www.zeph.com/>) called a ZT-6 Hot Air Fountain. I was turned on to
> this system from a Technetter named Steve Sauer. I couldn't rework
> anything on this board without damaging pads, barrels, or the PCB itself
> until I got the ZT-6.
>
> I put some pictures up on my web page a while back of me pulling a 96-pin
> connector out of that board. Look at:
>
> <http://www.stevezeva.homestead.com/files/ZT6.jpg>
> <http://www.stevezeva.homestead.com/files/TakingTemperature.jpg>
> <http://www.stevezeva.homestead.com/files/JustAbout.jpg>
> <http://www.stevezeva.homestead.com/files/ItsOut.jpg>
>
> There's a picture of the unit, me monitoring the temperature with a
> hand-held, non-contact, I/R Thermometer, me getting ready to pull the
> connector out, and then me finally pulling the connector out with a pair
> of tweezers...couldn't be easier!
>
> -Steve Gregory-
>
> << File: JustAbout.jpg >> << File: TakingTemperature.jpg >> << File:
> ZT6.jpg >> << File: ItsOut.jpg >>
>
>
> 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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