Steve,
I agree with both George and Edward.  
The best clue (even before looking at the pictures) was your statement that the smaller size hole was affected.  Smaller holes are more difficult to drill smoothly, shall we say.  When looking at the rows of holes, note that the roughness defect looks nearly identical in each hole.  Regarding ENIG, it is a pretty thin coating - too thin to add significantly to topography.  Any defect from it would more likely show up as poor coverage or as a salting-out (sanding?) type of defect.  A gas bubble defect normally shows up as a perfect ring somewhere in the hole barrel and usually would prevent plating coverage in that area.  

Patty
Patricia J. Goldman
PPG Industries, Inc.
724-274-3417
[log in to unmask]


-----Original Message-----
From: Edward Szpruch [mailto:[log in to unmask]]
Sent: Wednesday, November 21, 2001 1:03 AM
To: [log in to unmask]
Subject: Re: [TN] Rough PTH barrel walls in ENIG plated PCB...


Steve,
I completly agree with George.It has nothing with ENIG.Probably too rough
drilling or too agresive desmear.
ENIG finishing does follow surface geometry.This is contrary to HASL,that
fill some of valleys giving impression that the hole is smooth.
By the way,if the cross sections are OK, solder float tests wre OK ( copper
mechanical properties) and they do not  create problems in soldering (
cleaning etc) ,and if there diameter is OK, I do not see reasons for reject.
Edward 
Edward Szpruch
Eltek Ltd
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel  ++972 3 9395050 , Fax  ++972 3 9309581
e-mail   [log in to unmask]

> -----Original Message-----
> From: George Milad [SMTP:[log in to unmask]]
> Sent: ã ðåáîáø 21 2001 4:46
> To:   [log in to unmask]
> Subject:      Re: [TN] Rough PTH barrel walls in ENIG plated PCB...
> 
> Steve, 
> The holes on your site look like rough drilling. 
> ENIG mimicks the appeareance of whatever substarte it is plated on. These
> holes were rough before ENIG plating. 
> If a crossection shows adequate copper plate then the roughness could be
> non consequential. If u need to talk more about this e-mail me at
> [log in to unmask] 
> George Milad 
> Shipley

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------