Hi Ted,
> Is there any data that suggests that conductive epoxies or fillers 
> shouldn't be used at a specific aspect ratio?
> A: No data like that in the public domain, at least.

> What are the chances that the conductive epoxy is increasing hole wall pull 
> away, damaging the barrel?
> A: None, Hole wall pull away, ot resin ressesion, is the result of 
hydro-static [actually resin-static] pressure surrounding the via barrel trying to 
collapse it, and partially succeeding in terms of plastic deformation of the Cu 
barrel wall—putting anything into the via reduces the collapsing depending on the 
CTE of the fill material.

>  Can non-conductive fillers act as an insulator when it comes to heat 
> transfer within the barrel?
> A: Non-conductive filler will provide better heat transfer than air, but less 
than any other type of filler.

Werner



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