======== Original Message ========
I also agree that change in season has an effect on laminate.  It seems
that every spring when the humidity increases, layer to layer and
internal registration scrap increases as well.  It usually takes the
lamination department about a month to re-size artworks to adjust to the
changes in the laminate.  Regarding laminate cure, does everyone rely on
the results of a TMA and DSC or are there other tests to further evaluate
the cure of the laminate?

I have some experience drilling solventless laminate and I have not seen
any differences in registration from standard resin systems.  However,
after analysing the drills, solventless laminate abraids the carbide a
little less than conventional laminate.  One last comment is that
solventless  laminate drills a little dustier...is it dryer?

mf
On Thu, 28 Aug 1997 18:12:24 -0700 drilbert <[log in to unmask]>
writes:
>I agree Glenn.  Over the years I have seen drilling process data that
>suggests the laminate drills differently with the seasons.  However,
>the
>cure never seems to be off.  I wonder how humidity might affect the
>behavior of the laminated panel.
>More recently I have heard that laminate suppliers will be changing to
>a
>sovlentless process.  How might this affect the material behavior?
>Does
>anyone have any information on this?
>Drilbert
>[log in to unmask] wrote:
>>
>> Richard,
>>         Could it be the change of seasons?  I believe  humidity and
>> temperature have an affect on several processes from the weaving
>operation, to
>> impregnation at the laminator, to stack-up, and press.  But, I don't
>have any
>> hard data to prove it.  Maybe the gremlin is Mother Nature in
>disguise.
>>
>> Glenn Pelkey
>> Quality/Reliability Engineer
>>
>> Richard MacCutcheon <[log in to unmask]> Wrote:
>> |
>> | We seem to have developed a gremlin in our registration
>> | dept.
>> | A very large portion of scrap is attributed to NO Annular
>> | Ring (<.002").
>> |
>> | Over 90% of our product is 8-layer GIL with 2 and 7 as
>> | ground planes.
>> | Cores are .005 constructed of 1-106 and 1-2313.  Prepreg
>> | is 2313.
>> |
>> | Layer to layer misregistration is around .005" on average.
>> |  Artwork pad
>> | sizes are .022" over the max acceptable hole size.
>> | Tooling seems to be as
>> | tight as ever but in the last few weeks we have had an
>> | inordinate amount of
>> | scrap due to NO Annular Ring.
>> |
>> | What is the best systematic approach to take in
>> | identifying the problem(s)?
>> |
>> | Thanks for your time.
>> |
>> | Richard MacCutcheon
>> |
>
======== Fwd by: Richard MacCu ========
We have verified our scaling numbers and seem to be well within the
allowance given for variation in day to day humidity swings.

We have identified a flaw in the artwork tooling, punching to a first
article, which induces some significant layer-to-layer error.

The next potential area of improvement comes from the fact that after
post-bake of the laminated panels, the locations of the tooling holes have
shrunk along with the circuitry.  We have then been putting the soft tooling
holes in at there original location when setting up to drill.

Question 1:  Has anyone "scaled" their tooling hole locations for drilling
to compensate for the panel shrink?

question 2:  Are four tooling holes at the corners of the panel any better
than two on the centerline axis?

Richard MacCutcheon