Date: Tue, 11 Dec 2001
00:00:04 -0600
Subject: TechNet Digest - 10 Dec 2001 (#2001-770)
There are 6 messages totalling 573 lines in this issue.
Topics of the day:
1. RF shielding (2)
2. BGA Visual Inspection - Name Correction
3. BGA Visual Inspection - Name Correction (OOOPs)
4. Conformal Coating Process
5. Looking for flex design and build shop
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Date: Mon, 10 Dec 2001 16:24:03 -0500
Subject: Re: RF shielding
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Here's the additional link, that I was referring to from an earlier
post:
I don't know of the cost or delivery -- just remember seeing this
product
while browsing for similar information. Again, good
luck.
Steve Sauer
Date: Mon, 10 Dec 2001 16:41:11 -0600
Subject: Re: RF shielding
MIME-Version: 1.0
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Pardon me, but I'm not sure I understand why the cage should be
isolated
instead of grounded. Wouldn't 'grounding' the cage provide
better
'isolation' from test station to test station, instead of just
bouncing or
reflecting the signal, like I imagine an isolated cage would
do?
Currently we avoid crosstalk by planning what test stations are
placed
where, so that we don't put unshielded tests nearby critical
spurious tests
on another product line, for example. But as we get crowded,
waiting for
our new 'triple the size' production facility to be ready, we are
running
out of room to space our test stations adequately. In our new
building,
there will be no competing product line test benches backing on to
each
other - they will just have to worry about the ones to either
side...
Thanks.
-----Original Message-----
Sent: December 10, 2001 3:18 PM
Subject: Re: [TN] RF shielding
Hi Genny,
To further the info from Phil, here's some info regarding the
copper
You can make a screen cage with 2x4's, mesh, lag bolts and
washers. The
critical thing would be to ensure that the washer completely covers
the hole
made in the screen for the lag bolt to pass through. One side
note, the
cage doesn't need to be grounded, it should be isolated.
There are some commercially available products that may fit your
needs, such
as a portable "tent" that is made of aluminum poles and
EMI shielded
material. If I can find that information, I'll pass it along
later....
Good Luck.
Steve Sauer
Mfg Engineer
Xetron Corporation
-----Original Message-----
You could try copper window screen material....
I seen this successfully used for a high voltage faraday cage and it
is also
used on our EMC compliance test room.
Phil Nutting
-----Original Message-----
Looking for ideas - preferably more along the lines of homemade
basket
idea..... RF screen or something that we can mount and ground
between the
benches to reduce what we call 'crosstalk'.
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Date: Mon, 10 Dec 2001 14:50:47 -0800
Subject: Re: BGA Visual Inspection - Name Correction
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Glenn Woodhouse,
How are thing in Nampa?
It's been a while.
I was searching through the Technet (I have about 2700 unread in a
folder)
and I came across your name. This was from a post back in
August.
A couple mouse clicks later and I notice that you posted today
from
MCMS. Glad to hear that your still there.
Are things going well? Comparatively?
BTW the e-mail back in august had some great information about
AOI.
Did MCMS purchase an AOI? Can you tell me which one? Are
you happy with
the choice?
Thanks
Paul Gill
Sr. Process Development Engineer
Finisar Corporation
1 408 541 5626
-----Original Message-----
Sent: Monday, December 10, 2001 9:06 AM
Subject: Re: [TN] BGA Visual Inspection - Name Correction
Whoops. For anyone trying to search for the BGA inspection
scope I posted
on, I completely botched the spelling of the company and
product. The
Sorry for any inconvenience,
Glenn
Woodhouse
MCMS
Advanced Technology Development
> -----Original Message-----
> From: Glenn Woodhouse
> Sent: Monday, December 10, 2001 8:35 AM
> To: 'TechNet'
> Subject: RE: BGA Visual
Inspection
>
> Greg,
>
> The ERSA is a fine piece of equipment. When considering
it you must take
> into account the production environment it must survive.
The prism used
> in the tip is vulnerable to damage (i.e., collisions with
components such
> as caps and resistors around BGA's). Replacement is
costly and requires
> sending the tip assembly to ERSA for replacement. When we
evaluated the
> ERSA Scope a year ago, the repair process was to provide ERSA
with a p.o.
> (several hundred $'s), they would send out a loaner tip, you
would send
> your tip to ERSA where it would be repaired in Germany, weeks
later you
> would receive your tip back and either be partially credited
or
> additionally billed depending on the extent of the damage and
difficulty
> of the repair, and then you would send the loaner back to
ERSA. This
> cumbersome and costly process may have since changed but you
would want to
> check into this.
>
> There is another scope, the Cal-Tech "Hi-Roc" scope
that is very similar
> in cost and performance but utilizes easily replaceable (takes
minutes
> with your own people) plastic prisms. We did a
side-to-side comparison
> and this is what we ultimately bought. We could not
discern any
> appreciable difference in optical quality between the two
although the
> Hi-Roc uses a plastic prism and the ERSA uses a glass
one. Because we
> were using the scope in a volume production inspection process
we couldn't
> live with the replacement costs associated with the ERSA.
Within the
> first couple of months we replaced at least four prisms until
the
> production shifts got comfortable with the level of delicacy
associated
> with this type of equipment.
>
> If you will be using your scope in more of a lab inspection
environment
> with control over who is using the scope and the training they
have
> received, this level of prism damage likely won't occur, but in
my humble
> opinion it is still a matter of "when" the prism gets
damaged, not "if".
>
> ERSA has a very nice software package available with their
machine that
> includes prepopulated component images that display acceptable
and
> rejectable conditions along with the live image of the part
under
> inspection, including potential root cause comments. You
can add to and
> customize this image/comment library for your own criteria and
conditions.
>
> Good Luck,
>
> Glenn
Woodhouse
>
MCMS
> Advanced Technology Development
>
> ----- Original Message -----
> Sent: Friday, December 07, 2001 8:43 AM
> Subject: [TN] BGA Visual Inspection
>
>
> > > TechNet Friends,
> > > We are looking
into visual inspection of BGAs to supplement our
> > > X-Ray inspection. I am somewhat familiar with
the ERSASCOPE. It
> appears
> > > to be a fully developed, well-thought out system,
with all the options
> to
> > > make life easy. It appears that their
supplemental tools in fact, do
> add
> > > value to the endoscope itself. This, of course,
comes at a price.
> > > I'm hoping to
hear from people who have personally evaluated
> such
> > > tools.
> > > Are all the
features of the ERSA truly benefits?
> > > Are there other
systems that do what the ERSASCOPE does? Are
> they
> > > as fully developed as the ERSA?
> > >
> > > Thanks for your help with this one,
> > >
> > >
> > > Greg Anderson
> > > Senior Advanced Manufacturing Engineer
> > > GE Fanuc Automation
> > > Charlottesville, VA 22911
> > > Phone: 434-978-5181
> > > FAX: 434-978-5898
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Date: Mon, 10 Dec 2001 14:58:38 -0800
Subject: Re: BGA Visual Inspection - Name Correction (OOOPs)
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My last post was intended only for Glenn.
Some times the fingers are faster than the mind.
Paul Gill
Sr. Process Development Engineer
Finisar Corporation
1 408 541 5626
-----Original Message-----
Sent: Monday, December 10, 2001 2:51 PM
To: TechNet E-Mail Forum.
Subject: RE: [TN] BGA Visual Inspection - Name Correction
Glenn Woodhouse,
How are thing in Nampa?
It's been a while.
I was searching through the Technet (I have about 2700 unread in a
folder)
and I came across your name. This was from a post back in
August.
A couple mouse clicks later and I notice that you posted today
from
MCMS. Glad to hear that your still there.
Are things going well? Comparatively?
BTW the e-mail back in august had some great information about
AOI.
Did MCMS purchase an AOI? Can you tell me which one? Are
you happy with
the choice?
Thanks
Paul Gill
Sr. Process Development Engineer
Finisar Corporation
1 408 541 5626
-----Original Message-----
Sent: Monday, December 10, 2001 9:06 AM
Subject: Re: [TN] BGA Visual Inspection - Name Correction
Whoops. For anyone trying to search for the BGA inspection
scope I posted
on, I completely botched the spelling of the company and
product. The
Sorry for any inconvenience,
Glenn
Woodhouse
MCMS
Advanced Technology Development
> -----Original Message-----
> From: Glenn Woodhouse
> Sent: Monday, December 10, 2001 8:35 AM
> To: 'TechNet'
> Subject: RE: BGA Visual
Inspection
>
> Greg,
>
> The ERSA is a fine piece of equipment. When considering
it you must take
> into account the production environment it must survive.
The prism used
> in the tip is vulnerable to damage (i.e., collisions with
components such
> as caps and resistors around BGA's). Replacement is
costly and requires
> sending the tip assembly to ERSA for replacement. When we
evaluated the
> ERSA Scope a year ago, the repair process was to provide ERSA
with a p.o.
> (several hundred $'s), they would send out a loaner tip, you
would send
> your tip to ERSA where it would be repaired in Germany, weeks
later you
> would receive your tip back and either be partially credited
or
> additionally billed depending on the extent of the damage and
difficulty
> of the repair, and then you would send the loaner back to
ERSA. This
> cumbersome and costly process may have since changed but you
would want to
> check into this.
>
> There is another scope, the Cal-Tech "Hi-Roc" scope
that is very similar
> in cost and performance but utilizes easily replaceable (takes
minutes
> with your own people) plastic prisms. We did a
side-to-side comparison
> and this is what we ultimately bought. We could not
discern any
> appreciable difference in optical quality between the two
although the
> Hi-Roc uses a plastic prism and the ERSA uses a glass
one. Because we
> were using the scope in a volume production inspection process
we couldn't
> live with the replacement costs associated with the ERSA.
Within the
> first couple of months we replaced at least four prisms until
the
> production shifts got comfortable with the level of delicacy
associated
> with this type of equipment.
>
> If you will be using your scope in more of a lab inspection
environment
> with control over who is using the scope and the training they
have
> received, this level of prism damage likely won't occur, but in
my humble
> opinion it is still a matter of "when" the prism gets
damaged, not "if".
>
> ERSA has a very nice software package available with their
machine that
> includes prepopulated component images that display acceptable
and
> rejectable conditions along with the live image of the part
under
> inspection, including potential root cause comments. You
can add to and
> customize this image/comment library for your own criteria and
conditions.
>
> Good Luck,
>
> Glenn
Woodhouse
>
MCMS
> Advanced Technology Development
>
> ----- Original Message -----
> Sent: Friday, December 07, 2001 8:43 AM
> Subject: [TN] BGA Visual Inspection
>
>
> > > TechNet Friends,
> > > We are looking
into visual inspection of BGAs to supplement our
> > > X-Ray inspection. I am somewhat familiar with
the ERSASCOPE. It
> appears
> > > to be a fully developed, well-thought out system,
with all the options
> to
> > > make life easy. It appears that their
supplemental tools in fact, do
> add
> > > value to the endoscope itself. This, of course,
comes at a price.
> > > I'm hoping to
hear from people who have personally evaluated
> such
> > > tools.
> > > Are all the
features of the ERSA truly benefits?
> > > Are there other
systems that do what the ERSASCOPE does? Are
> they
> > > as fully developed as the ERSA?
> > >
> > > Thanks for your help with this one,
> > >
> > >
> > > Greg Anderson
> > > Senior Advanced Manufacturing Engineer
> > > GE Fanuc Automation
> > > Charlottesville, VA 22911
> > > Phone: 434-978-5181
> > > FAX: 434-978-5898
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Date: Mon, 10 Dec 2001 23:17:54 -0000
Subject: Re: Conformal Coating Process
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Doug and Jim
In respect to the suggestions Doug makes, could you just be sure
that you
are manufacturing assemblies that are broadly in-line with the
"coupon
design" outlined in J-Std001/004/TM650 etc..
Latest research suggests that "older" designs might yield
grossly misleading
reliability data (SIR results) - you really must test to conditions
to which
your finished assembly shall be subjected.
"Cleaning" to a value of less than 2 megohm/cm also means
that it is
acceptable to leave up to that amount of "salt" on every
square cm of the
assembly, but fine-line; fine-pitch; COB, BGA etc., might well
demand a far
lower value. I know of many that work to less than 0.2 megohm/cm for
this
very reason.
Regards, Graham Naisbitt
For instant access to Product Data Sheets register on the Tech-Shot area of
Concoat Limited
Alasan House, Albany Park
CAMBERLEY GU16 7PH UK
Phone: +44 (0)1276 691100
Fax: +44 (0)1276 691227
Mobile: +44 (0)79 6858 2121
-----Original Message-----
Sent: Monday, December 10, 2001 02:12
Subject: Re: [TN] Conformal Coating Process
I'm trying to qualify a new cleaning process for electrical assemblies
prior
to conformal coating (Military boards). The old MIL Specs had as
cleanliness requirement of 2 meg-ohms minimum, is this all I need to do,
verify cleanliness to 2 meg-ohms? What about subjecting the assemblies to
10-day elevated temp/humidity (steady state)? Any recommendations?
*Jim, to your first question, Yes. When changing a cleaning operation, and
not changing fluxes, MIL-STD-2000A only required Appendix C testing, which
was the standard ROSE test. The 2 megohm-cm requirement translates to the
more familiar 10.06 micrograms sodium chloride equivalence per square inch,
whatever that becomes translated to the specific ionic cleanliness tester.
We all know what a crock that test is, but it still exists, especially in
military contracts.
Two questions you should be asking: What data does my customer need to
see? and I just trying to meet contractual requirements or REALLY show that
the change is not detrimental?
If the customer leaves it totally to you, then I suggest that you do both.
The ROSE test, bogus as it may be, is very easy to do and satisfies the
contractually focussed types. As to a longer temperature-humidity
exposure, that is a fairly good idea. What tests to you perform now to
tell you if product is good or bad? Do that same test but extend the test
time about 50% and run on hardware cleaned with the new method. At
Collins, our products go through -55 to 125C cycling to catch infant
mortality types of failures, er...ahhh... not that we EVER see such
failures, mind you....., and when we have a process change, we use the same
environmental screen.
Doug Pauls
Rockwell Collins
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Date: Mon, 10 Dec 2001 15:49:12 -0800
Subject: Re: Looking for flex design and build shop
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Hi Terri,
We have a lot of experience with this type of flex. Please check out our
Debbie Kenney
Engineer
M-Flex / AMT
Direct (714) 688-5242
Fax (714) 996-3834
> -----Original Message-----
> Sent: Monday, December 10, 2001 5:20 AM
> Subject: [TN] Looking for flex design and build shop
>
> Hi All,
>
> I'm looking for a shop to design and build an oddly twisted, Y-shaped flex
> circuit with connectors at the 3 ends. It must be shielded (3 layer) and
> must withstand temperatures from -40 to 100C. Volumes are relatively low
> (a
> few thousand/year).
>
> If any of you have good experience with such a shop that does this for a
> living, please send me contact information off TechNet.
>
> Thanks in advance,
> Terri
>
>
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