Paul,

I consider the argument false logic based on the idea that one can see too
much at high magnification.  This idea is simply not true.  One should be
able to diagnose crazing without fear of overstating the problem in
microsections.

Ed Hare


On Thu, Dec 5, 2013 at 1:05 PM, Paul Reid <[log in to unmask]> wrote:

> I was just on a conference call where we found crazing (a separation
> between glass fibers and the epoxy system), in a microsection. The
> fabricator stated that this had to be evaluated looking at a board
> macroscopically and could not be evaluated microscopically.
>
>
>
> Crazing is called out in IPC-A- 600 in section 2, paragraph 2.3.2 page
> 18, which is "Externally Observable Characteristics". In A-600 there is
> picture of a microsection showing the defect but it states that a
> microsection is not required.
>
>
>
> In IPC 6012-2010 crazing is call out in 3.3.2.2, page 12, which states
> (I am paraphrasing), "Crazing shall not violate greater than 50% of the
> distance between adjacent conductors..." The document then refers to IPC
> A 600.
>
>
>
> What is your take on their argument that crazing should not be evaluated
> microscopically as per IPC?
>
>
>
> Sincerely,
>
>
>
> Paul Reid
>
> Program Coordinator
>
> PWB Interconnect Solutions Inc.
> 235 Stafford Rd., West, Unit 103
> Nepean, Ontario Canada, K2H 9C1
>
> 613 596 4244 ext. 229
>
> Skype paul_reid_pwb
> [log in to unmask]
>
>
>
>
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-- 
Ed Hare
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