Larry Campbell;
I guess I have to respond to this..huh
Hello Lou..
First, My bases for my respond was follows..
It's based on 30 years of experience with
large number of Fab Houses...
Not seeing your design, I can only guess at
what is actually going on...
Fab houses fall into to groups, no can do! and can do!
usually the no can do has a goal.
One, to make there job easier.
Two, to incease there yield.
Three, use material that they have on hand.
Four, use old equiptment.
There's nothing wrong with these goal..
Except if the performance of the board suffers or it costs
me time to incorpate there requests..
Ideas about your board house...
If the board house is using inferior FR4, that
has a lower peel strength. They could have problems.
Not using high speed drilling equiptment.
Dull or worn out drill bits.
Are they using SPC? Are they ISO9000?..
Some ideas about your design...
The design could have insufficent annular ring.
Which would cause breakout, not spinning pads
I wonder why all the other un-surported holes on other
internal layers don't spin. I never seem thermal reliefs
place on pads to keep them from spinning..
Ask your vendor what kind of cost reduction you will
recieve if you stop the spinning pads.
I would get a second opinion !!!..
I also heard alot of excuses for not meeting
schedules including blaming the design..
You get my drift..
Disclamier ...My opinion
Lou
>
> ______________________________ Reply Separator _________________________________
> Subject: Inner layer pad suppression
> Author: [log in to unmask] at corp
> Date: 9/30/96 7:24 AM
>
>
> To Jeff Foster and Louis T. Dallara,
>
> Last week I wrote:
>
> " but there has been no documentation that I have seen. One vendor doesn't
> like to have them because he believes of the possibility of spinning the
> internal pad since there is no track to hold it in place. This may or may
> not be a valid point. "
>
> I'm sure you guys think you have a point, but you failed to mention what it
> was. Show me something other than your opinions. I need something
> quantatative. Give me something in print. I'm only relaying what one board
> vendor told me. As stated, it MAY or MAY NOT be a valid point, but since
> there's nothing to prove OR disprove it, the board vendors opinion is just as
> valid, if not more so, than your responses. He has to make the boards and
> sell them to me. If he feels this is a point to increase his yeild, and there
> is nothing to disprove him (and you didn't do that), then there is nothing
> wrong with his reasoning.
>
> I read and respond to this board for one reason only, to give input and to
> learn, not to see myself in print.
>
> Larry Campbell
> Supervisor, PWB
> BFGoodrich, Avionics Systems
>
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