This oxidized copper approach could add cost to the board since we 
     fabbers now have to cover the fiducial <somehow> at HASL. We do have 
     the means, but go explain that to the guy(s) placing dots all over the 
     panels....


______________________________ Reply Separator _________________________________
Subject: Re: ASSY: Polishing Fiducials
Author:  [log in to unmask] at INTERNET_GATEWAY
Date:    11/12/96 2:13 PM


Allen Hertz wrote:
> 
>      Pat,
> 
>      That concept works well. The term "Pink Pearl" was coined as the 
>      processes since one would purchase a number of those little pink
>      erasers and go scrub fiducials. This was effective for HASL or other
>      tin-lead finished boards.Gold or OSP finsihes generally do not require 
>      this operation.
> 
>      An alternative used was to place lighting under the board and change 
>      the PCB layout by removing all metallization and resist around and
>      under the fiducial. The "backlighting" provides a silhouette,
>      eliminating any variations due to reflection. This is a major task, 
>      especially for various board sizes.
> 
>      Regards,
>      Allen Hertz
>      [log in to unmask]
> 
> ______________________________ Reply Separator 
_________________________________
> Subject: ASSY: Polishing Fiducials 
> Author:  [log in to unmask] at ftl03
> Date:    11/12/96 12:48 PM
> 
> >From the What Will They Think Of Next (WWTTON) dept:
     
 Another request we`ve had in this light (sic) is to leave 
 the fiducials as bare copper, allowed to oxidize.  Brings 
 an OSP-look to a HASL PWB.
     
 Regards,
-- 
     
      Jeff Seeger                             Applied CAD Knowledge Inc 
      Chief Technical Officer                      Tyngsboro, MA  01879 
      [log in to unmask]                               508 649 9800
     
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