It started maybe 5 to 6 months ago.



>______________________________ Reply Separator 
_________________________________
>     Has this problem just started recently or has it been an ongoing
>     problem for some length of time?
>     
>     
>     Terry Pearo
>     Marcel Electronics
>
>
>______________________________ Reply Separator 
_________________________________
>Subject: FAB: hole burrs
>Author:  [log in to unmask] at Internet
>Date:    12/11/96 2:55 PM
>
>
>We are experiencing sporadic instances of copper burrs after deburring.  It 
>appears that the deburr brushes are "shaving" burrs and almost but not quite 
>removing them.  Describing the condition as a burr may be misleading because 
>most people think of a burr as protruded copper.  These burrs exist when the 
>surface is 100% smooth and free of surface burrs after drill . What is left 
>is a curl of copper protruding the hole. What we have observed and done so far:
>     
>-When it happens, it is on the whole job-maybe a 2 panel run, maybe a 100 
>panel run.
>     
>-it occurs on multilayer and double sided panels.
>     
>-it happens on .5 ounce through 2 ounce foils.
>     
>-we have tried every combination of brushes.  320 grit works as well as 
>anything else. (The deburr machine has 2 brushes top, 2 brushes bottom.  The 
>operators are performing brush footprint checks several times a day.
>     
>-it appears to be on the top side of the panel as it is drilled. We have had 
>our drill tool supplier in (inconclusive)and have emphasized the obvious to 
>the drill operators-clean between panel stacks, make sure depth is correct, 
etc.
>     
>Any ideas?
>     
>thanks,
>     
>Lyle Anderson
>[log in to unmask]

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