Exactly my point....neither is coating boards to 20 mils thick with SR
conformal coating, but yet we get told to do just that. Isn't that right
Mr.Gregory?...lol
Lloyd Duso
Diamond-MT
Plant Manager
(814) 535-3505
www.Diamond-mt.com
On Wed, Mar 4, 2015 at 3:01 PM, SALA GABRIELE <[log in to unmask]> wrote:
> even not in the HDBK-830
>
> Gabriele
>
> -----Messaggio originale-----
> Da: TechNet [mailto:[log in to unmask]] Per conto di Guy Ramsey
> Inviato: mercoledì 4 marzo 2015 20.26
> A: [log in to unmask]
> Oggetto: Re: [TN] Required Conformal Coating of Edges of PCB's
>
> Beware of false knowledge. It is more dangerous than ignorance.
> This is not in the J-STD-001F, or IPC-CC-830B.
>
> Guy
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of lduso - Diamond-MT.com
> Sent: Wednesday, March 04, 2015 12:26 PM
> To: [log in to unmask]
> Subject: Re: [TN] Required Conformal Coating of Edges of PCB's
>
> All I can add is this: As coating application contractor we have had
> hundreds of customers over the years and thousands of part numbers.
> Everything from NASA Maven to paintball gun CCA's. In all that I think I
> had
> two part numbers in 8 years that the customer required the edge to be
> coated. One claimed that the reason was to seal the edge of the board and
> the other said it was because there was copper extremely close the edge.
>
> As everyone has said, it's something worked out between us and the
> customer.
> The funniest part is that they all claim it is in accordance with the IPC.
>
> Lloyd Duso
> Diamond-MT
> Plant Manager
> (814) 535-3505
> www.Diamond-mt.com
>
> On Wed, Mar 4, 2015 at 9:18 AM, Richard Kraszewski <
> [log in to unmask]> wrote:
>
> > Thanks to all for the great insights & discussion on this topic.
> >
> > Rich Kraszewski
> > PLEXUS
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg Owens
> > Sent: Tuesday, March 03, 2015 10:19 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Required Conformal Coating of Edges of PCB's
> >
> > I vote great minds! :)
> >
> > Gregg
> >
> > -----Original Message-----
> > From: Stadem, Richard D. [mailto:[log in to unmask]]
> > Sent: Tuesday, March 03, 2015 7:36 AM
> > To: TechNet E-Mail Forum; Gregg Owens
> > Subject: RE: [TN] Required Conformal Coating of Edges of PCB's
> >
> > Gregg, I posted almost the same thing and sent it before I saw your
> > posting. Great minds think alike, or something like that, I guess!
> > dean
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Gregg Owens
> > Sent: Tuesday, March 03, 2015 9:31 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Required Conformal Coating of Edges of PCB's
> >
> > Standards do not necessarily define every possible condition,
> > exemplified by this thread's conversations. I am sure the standard
> > committee members for conformal coating need to take note of this
> > condition and come to some conclusion in future editions of the
> > standard. The problem becomes "it depends" is sometimes the right answer
> for some criteria in IPC standards.
> > That is where the standards state: AABUS (as agreed to between user
> > and supplier (manufacturer)).
> >
> > We live in a complex world where decisions making becomes convoluted
> > between user (customer) and manufacturer. Some users depend on the
> > manufacturer's experience for best industry practices because they may
> > know very little about electronics manufacturing processes let alone
> > end-use implications of those processes (e.g. whether or not to
> > conformally coat a board, what type of coating to use and coverage
> requirements).
> >
> > I live in a bubble where engineering resides with production and
> > communication is very near seamless. So such issues can effectively
> > and efficiently discussed and quickly and effectively decided upon. In
> > the real world of contract manufacturers this rarely exists.
> >
> > If life were easy, most of use would not be needed.
> >
> > Gregg
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Dale Ritzen
> > Sent: Tuesday, March 03, 2015 7:07 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Required Conformal Coating of Edges of PCB's
> >
> > Seriously folks... is this a real or imaginary problem? We have seen
> > both "yes" and "no" opinions over the last several days. Is anyone
> > basing their opinions on a specific standard that states what
> > conditions require the PCB edges to be coated, or is it simply a
> > matter of the customer specifying that requirement on their S.O.W. for
> > the product? Are manufacturers to second guess the customer about the
> > places the product will be used and the environmental conditions it
> > will be placed in that might warrant coating of the PCB edges, or does
> > that really matter anymore with the state of the art PCB manufacturing
> > processes - regardless of the condition of the material left on the
> > edges (with the possible exception of PCBs made of Polyimide materials)?
> >
> > So far we have seen opinions - not quotes from any standard that
> > covers this. Does that exist, or is it something that the IPC
> > technical committees need to look into for further definition? Sounds
> > to me like it needs some definition in a standard so we all have
> something
> to march to...
> >
> > IMHO,
> > Dale Ritzen, ASQ CQA
> > Quality Manager / ISO Management Representative
> > ___________________________ Austin Manufacturing Services
> > ______________________________________________________________________
> > _____________________________________________________________________
> > This email and any attachments are only for use by the intended
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> > you have received this email in error, please notify the sender
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> >
> >
> >
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce
> > Koo
> > Sent: Monday, March 02, 2015 5:20 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] Required Confromal Coating of Edges of PCB's
> >
> > also there are cut off edges of the PWB like using shear... really bad
> > with all the fiber glass stick out.... there is not enough coating can
> > fix that... (don't laugh, those are real surprise you get from far)...
> > jk
> > On Mar 2, 2015, at 10:04 AM, Stadem, Richard D. wrote:
> >
> > > You lost me on that post, Wayne.
> > > Not sure what you are trying to describe when you talk about
> > > drilling thousands of overlapping holes as a method of routing out a
> PWB?
> > > The edge-coating being discussed was conformal coating, not plating
> > > of the edges?
> > > Sorry if I am slow on the uptick today.
> > > dean
> > >
> > > -----Original Message-----
> > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> > > Sent: Monday, March 02, 2015 8:44 AM
> > > To: [log in to unmask]
> > > Subject: Re: [TN] Required Confromal Coating of Edges of PCB's
> > >
> > > I feel the need to point out the obvious:
> > >
> > > -Suppose we singulated a board by using a pcb drill, drilling
> > > thousands of overlapping holes. It's hard to keep drills sharp, so
> > > let's assume we just swap out bits after the same number of "hits"
> > > that we deem the bit good for via hole drilling. Now how 'bout we
> > > coat the exposed edge with plated metal, just to make sure that if
> > > there's a problem with the drilling/routing process, we have a real
> > > good chance of making a short.
> > >
> > > Any reason that should be dis-allowed? Try calculating the exposed
> > > area on the edge vs. all of the via circumferences you've got!
> > >
> > > Therefore, it's ridiculous to specify coating of routed board edges,
> > > which if anything, have less potential to damage fiber bundles than
> > > a drill. Snapped areas are a different category because
> > > drilling/milling has a limited capability to damage the laminate.
> > >
> > > Wayne
> > >
> > > -----Original Message-----
> > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
> > > Sent: Monday, March 02, 2015 9:26 AM
> > > To: [log in to unmask]
> > > Subject: Re: [TN] Required Confromal Coating of Edges of PCB's
> > >
> > > Rich,
> > > In addition to what Dr. Pauls has detailed below, I also want to
> > > point out that whether or not any specification "recommends" or
> > > "does not recommend"
> > > coverage on certain areas of components and PWBs, it is the assembly
> > > drawing which has historically taken precedence over all standards
> > > when it comes to defining conformal coating coverage.
> > > This is because every assembly and PWB has different design
> > > requirements and it would be too difficult to document all of the
> > > exceptions to the different rules for each type.
> > > Many circuit boards are simply blanked out on a press, leaving
> > > exposed fiberglass edges, but these are also typically high-volume,
> > > low-reliability PWBs used only for consumer electronics. All other
> > > PWBs are typically routed or laser cut, and as Doug stated those are
> > > typically sealed by the singulation process. Depending on the type
> > > of PWB material, the method of singulation, and the application,
> > > there may be no need to coat the edges.
> > > Or there might be, but then one would expect this to be detailed as
> > > part of the assembly requirements on the drawing.
> > >
> > > dean
> > >
> > > -----Original Message-----
> > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
> > > Sent: Sunday, March 01, 2015 8:07 PM
> > > To: [log in to unmask]
> > > Subject: Re: [TN] Required Confromal Coating of Edges of PCB's
> > >
> > > Rich,
> > > MIL-I-46058 is simply a materials qualification document. It does
> > > not address the coating of board edges. I would disagree with
> > > Graham and I do not believe that conformal coating edges of boards
> > > is a value added process. Most boards in high performance
> > > electronics have routed edges.
> > > The routing process tends to smear the resin over the glass
> > > reinforcement, sealing the edges. And since most design standards
> > > do not allow internal circuitry closer than 25 mils from the edge of
> > > the boards, water or external contaminants would have to penetrate
> > > 25 mils of epoxy resin to get to circuitry. If the edges of the
> > > boards were sheared or snapped, where the resin did not seal the
> > > ends, then perhaps the sealing would be justified. I can say that
> > > Rockwell has coated some board edges and left other edges free.
> > > We have no field failure, ever, that can be traced to lack of
> > > coating the board edges.
> > >
> > >
> > > Doug Pauls
> > > Principal Materials and Process Engineer Rockwell Collins
> > >
> > > On Fri, Feb 27, 2015 at 10:51 AM, Richard Kraszewski <
> > > [log in to unmask]> wrote:
> > >
> > >> Does anyone recall which MIL document calls out the requirement
> > >> to cover the PCB edges of assemblies?
> > >> I have been led to believe that one exists but that more than
> > >> likely it is not MIL-I-46058C.
> > >>
> > >> Any thoughts??
> > >>
> > >> Rich Kraszewski
> > >> Plexus
> > >>
> > >> ___________________________________________________________________
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