Hey Steve,
I know it's going to be tough abandoning the Dremel / Xacto methods
you've so nicely perfected, but alas ... time and technology move
onward!
A small vacuum chamber & pump are useful for getting the air out of
those sections that tend to trap air, like vias, connectors, under BGAs,
etc. The long pot life of the epoxies gives enough time to pump down
those mounts. We use a Struers Epovac chamber and a pump I just got for
a few hundred bucks out of the Grainger catalog. Most of our sections
are done in acrylic which is great for most purposes, but it sets up too
fast for evacuation.
Depending upon the epoxy you choose, a small oven to cure it over and
hour or two may be required.
Diamond wheels are very good for grinding sections with ceramics. Shop
around for these as they can be v-e-r-y expensive. Jeweler's supply
houses are a good source for them.
You'll want clips to hold sections in place in the cups. I prefer the
plastic roll clips over the metal clips. The less metal I have to grind
the better. Sometimes the adhesive-backed cardboard bases are useful
too, but the adhesive residues can gum up things at the beginning, so I
pass the section over a toss-away paper disk first before doing any
grinding on a diamond disk.
A standard variable-X stereo inspection scope w/good lighting mounted on
a shelf right above the X/S equipment saves a lot of walking back and
forth to somewhere else to see how the section is going.
If you get this capital equipment P.O. through the bean counters I'd be
willing to bet heavily that we're all going to get lotsa' chances to
brush up on our cross-section analysis ... Good luck.!
Bruce Tostevin
Benchmark Electronics
Hudson, NH
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Tuesday, October 04, 2005 9:25 AM
To: [log in to unmask]
Subject: [TN] Microsectioning equipment...
Morning Everybody!
As some of you might have read in my past posts, I don't have much
capability (read: none) for microsectioning PCB's in-house, other than
a Dremel tool and a desire to try and see things.
Things look like they will possibly be changing in the future as far as
our microsectiong needs...we will need to have at least a basic
capability
in-house to do a decent microsection. One of the things besides PCB
sections
that we will be looking at, is to be able to verify void-free underfill.
I'd like to ask those of you that do microsections all the time for a
favor. If
you had to set-up a basic capability from scratch, what would be the
minimum
things that you like to have. I can fumble around and eventually get
everything
I need, but I thought; "Why re-invent the wheel?" So I thought I would
ask
you all...
Just off the top of my head, these are some of the basic things of what
I
think I
should have:
1. Diamond saw
2. Series of grinding/polishing wheels
3. Potting molds
4. Potting materials
5. High magnification microscope
6. ?
If there are things that you would add to the list, please add them for
me.
If there
are certain vendors of the things on the list that you feel are better
than
others,
go ahead and list them as well. If you feel that you should respond
off-line on
those items, do that as well.
I'm not trying to set-up a full blown failure analysis lab, just
something
that will give
us the capability to spot some of the obvious problems from a
microsection.
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
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