Chris;
See the comments bellow, I have only ideas not experience since I never
worked with thin boards.
Here my R$ 0.035 that is 0.02 US$
Jorge Dourado de Santana
Maintenance / Process Engr
Microtec - Brazil
> -----Original Message-----
> From: Christopher Murphy [SMTP:[log in to unmask]]
> Sent: 10 de Abril de 2000 17:07
> To: [log in to unmask]
> Subject: [TN] Thin PCBs (or PWBs)
>
> Dear All,
>
> apologies if this question has been raised before. We are currently
> looking into running a 0.5mm thick double sided PCB (142mm wide) down
> one of our SMD lines, but do not want to use carriers as we are in a
> medium to high volume production environment and do not want the
> inefficiency of manually inserting and removing PCBs.
>
> Does anyone have any advice on how to go about this? We can design new
> vacuum supports for our placement machines and modify the locating pin
> type clamping mechanism so that it does not bow the PCBs upwards, but I
> cant figure out how to stop excessive sag on the PCBs during reflow.
>
>
>
> "If you have room in the board a steel wire can be put trough the oven
> to suport the board during reflow, the same way that is used in wave
> solder machines to support heavy FR2 boards, but this room is normally
> used at FR2 boards for wave soldering process and is considered at design
> phase of the board, it is very probably that you dont have this option.
> Another option that you can try is use of "solder guard" a tool made of
> titanium used at solder wave machine to protect golden contacts from
> soldering or to prevent solder to flow over the board during solder wave
> process, this toll you can sllip onto circuit board at rear and front
> side.( You can see the tool at Techni-tool catalog inside
> Soldering/Desoldering section ) and maybe can solve your problem, I never
> did this before it is just one ideia that is at your risk to try ( If it
> worked please tell me back !!)"
>
>
>
> Also how about machines which use edge clamping for the PCBs - we can
> ease the pressure of the clamping back to stop board bowing but wont the
> clamping force then be too low and allow the PCB to move?
>
>
> " In this case you can use fiducial option in all machines to compensate
> the board movement "
>
>
> For background info, the line consists of a Dek 265Lt, Fuji CP4-3,
> Philips Gem series machines (or Yamaha YV100, YVL88, YVL80), and a
> Heller 1500 reflow oven with pin and mesh conveyor.
>
> Any replies will be most appreciated !
>
> Thanks,
>
> Chris Murphy,
>
> Production Engineering Dept.,
>
> Tait Electronics
>
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