That was great!!!!  :-)


Quoting Francis Byle <[log in to unmask]>:
> But what do you do when you find eyebrow cracks? Brow-beat the supplier?
>
> Fritz
>
> -----Original Message-----
> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Whittaker,
> Dewey (EHCOE)
> Sent: Monday, November 09, 2009 12:50 PM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] Double-Blind Via Construction and IPC-6012C
>
> A good discussion; maybe: raise a few eyebrows; certainly. 
> Dewey
>
> -----Original Message-----
> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Denise
> Chevalier
> Sent: Monday, November 09, 2009 11:39 AM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] Double-Blind Via Construction and IPC-6012C
>
> More photos for thought - agree this will be a good discussion. 
> Typically see these defects in thin dielectric area. 
>
> -----Original Message-----
> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Lance A
> Auer
> Sent: Monday, November 09, 2009 11:59 AM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] Double-Blind Via Construction and IPC-6012C
>
> John,
>
>         This will be a good discussion, but it may interfere with your
> schedule for release of the next revision or 6012.   We certainly have
> seen small cracks between the pads in dual-bllind constructions.  They
> are
> termed "eyebrow" cracks since they appear above the pads on the blind
> holes.   As long as they are small and located adjacent to the pads, we
> have considered them to be "in the thermal zone" and acceptable.  It
> would
> be a good step forward to identify this structure and define actual
> accept/reject criteria. 
>
> Thanks,
> Lance
>
>
>
>
>
>
> John Perry <[log in to unmask]>
> Sent by: IPC-600-6012 <[log in to unmask]>
> 11/09/2009 09:07 AM
> Please respond to
> "(Combined Forum of D-33a and 7-31a Subcommittees)"
> <[log in to unmask]>
>
>
> To
> [log in to unmask]
> cc
>
> Subject
> [IPC-600-6012] Double-Blind Via Construction and IPC-6012C
>
>
>
>
>
>
> Hello Everyone,
>
> Recently, we updated the attached IPC-6012C Figure 3-9 to better
> illustrate requirements for laminate anomalies in Zone A and Zone B. 
>
> A question has come up regarding laminate anomalies in double-blind via
> constructions.  Please refer to the attached PowerPoint file.  The
> questions are:
>
>
> *         Are laminate defects in Zone A allowed after thermal stress?
>
> *         Are any defects allowed in the non-thermal stressed condition
> in
> Zone A?
>
> *         What would be the size of defects allowed?  Would they be the
> same as for standard PTHs?
>
> *         If defects allowed in non-stressed condition is there a
> minimum
> spacing requirement of resin/glass between layers?
>
> Let's discuss this through this IPC-600-6012 e-mail forum and see if
> there
> is a need to further update IPC-6012C Figure 3-9 (or duplicate it and
> modify as needed for double-blind constructions). 
>
> Regards,
>
> John Perry
> Technical Project Manager
> IPC - Association Connecting Electronics Industries(r)
> 3000 Lakeside Drive # 309S
> Bannockburn, IL 60015-1249 USA
> +1 847-597-2818 (tel)
> +1 847-615-7105 (fax)
> +1 847-615-7100 (Main)
> [log in to unmask]
> www.ipc.org
>
>
> [attachment "6012c-3-9.jpg" deleted by Lance A Auer/US/Raytheon]
> [attachment "Blind Via Defects 11-08-09.ppt" deleted by Lance A
> Auer/US/Raytheon]
>