Ioan
Just check that the smoke is not accumulated flux residue deposits on the "roof" of the oven.
Graham Naisbitt
On 7 May 2010, at 17:07, Ioan Tempea wrote:
> In case you guys thought you got away by talking about alien espresso machines, I have one more question.
>
> Took a bare board from stores and stuck it into the reflow oven. I have noticed smoke coming out from the tunnel while the PCB was in. Not huge or thick, but just enough smoke to notice it. Could this mean anything regarding the board, like not cured something, poor FR-4 or else?
>
> Thanks,
>
> Ioan Tempea, ing.
> Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
> T | 450.967.7100 ext.244
> E | [log in to unmask]
> W | www.digico.cc
>
> N'imprimer que si nécessaire - Print only if you must
>
>
>
> Dear Technos,
>
>
>
> Back to orange peeling, this time concerning conformal coating, please see
> http://ipc-technet.groupsite.com/galleries/photo/124230
>
>
>
> The coating is applied with an Asymtek Century machine and is a Conap 1170
> acrylic.
>
>
>
> ˇ The board is left curing in ambient temperature, no
> acceleration. Starting with an even coating, in about 20-30 minutes the
> liquid seems to move towards a certain area (no rippling at this moment).
> After another 10-15 minutes the rippling effect sets in.
>
> ˇ We thought that due to the almost 2 minutes lag between the
> coating of the first and last image, the drying of the coating layer is
> not even and the one side curing first pulls on the liquid at the other
> end. So we've cut the panel in 2, accelerated the machine, the problem is
> still there.
>
> ˇ The boards are laid as flat as possible, maybe not perfectly
> horizontal, but not worse than others with the same coating, that do not
> show any issue
>
> ˇ Just to make it more difficult: grabbed a non-populated panel
> from the stores, coated it, placed on the same flat surface, and guess
> what: no issues.
>
>
>
> The PCB has Taiyo PSR 4000 MP soldermask.
>
>
>
> So I would need your guidance in clarifying where is this coming from and
> how to fix it.
>
>
>
> Thank you,
>
>
>
> Ioan Tempea, ing.
> Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
> T | 450.967.7100 ext.244
> E | [log in to unmask] <mailto:[log in to unmask]>
> W | www.digico.cc <http://www.digico.cc/>
>
>
> N'imprimer que si nécessaire - Print only if you must
>
>
>
>
>
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