I think the contamination issue is with silicon grease not adhesive or potting compound.
There used to be a legend that the grease would 'migrate' into switches etc where it would cause open
circuits and be impossible to clean.
I'd be interested to know if anyone ever experienced this.
Regards,
[log in to unmask] wrote:
> The answer to your question is.......it depends. (How's that for not
> sticking my neck out?) As long as you use electronic grade silicone (RTV) as
> I mentioned in my previous post, then there is nothing in the material that
> will harm your board. Heck, when I was involved in building high voltage
> power supplies for military applications we potted the entire board in
> silicone to prevent coronal discharge (also known as lightning.) Silicone
> conformal coating is actually quite popular for certain applications.
> However, what I think you are referring to as far as contamination is when a
> board has to be conformal coated or potted with another material. In that
> situation, any silicone on the board will prevent adhesion of the coating so
> one must be very conscience of contamination issues. So, like most things in
> life, there is no absolute here. It all depends on your requirements,
> compatibility to the rest of the process and your individual process
> controls.
>
> Bob
>
> =======================
> Robert Barr
> Manufacturing Engineering
> Formation, Inc.
> Voice: 856-234-5020 x3035
> Fax: 856-234-6679
>
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]]On Behalf Of
> > [log in to unmask]
> > Sent: Wednesday, February 13, 2002 9:26 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] Adhesive Recommendations? Silicon??
> >
> >
> > Hi, All,
> >
> > I'm still trying to reconcile all the continued use of silicon adhesives
> > (as recommended by several learned members of this forum) with all the
> > learned discussion about how terrible it is to put silicon anywhere near
> > boards because of contamination issues. Is anyone prepared to put his/her
> > neck on the line and try for a definitive statement on this issue - is
> > silicon on boards good, OK or bad? If it's bad, why are so many
> > still doing
> > it? Is it Force Majeur, are there no alternatives, or is there a
> > mysterious
> > land out there where the use of silicon is not detrimental and
> > the benefits
> > are worth having? Which land is this?
> >
> > Peter
> >
>
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--
Eric Christison
Mechanical Engineer
STMicroelectronics
33 Pinkhill
Edinburgh
EH12 7BF
Tel: (0)131 336 6165
Fax: (0)131 336 6001
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