Fab capability is also dependant on material type. Drilling 
parameters are just first part of the problem. Then comes the 
chemical and fluid dynamics challenge. Different materials behave 
differently in hole prep and plating.

At 10:18 PM 2/10/2010, Shanmugam, Nagaraj wrote:
>  thanks for the answers.. Still I am looking for more information.
>Say if my Aspect ratio is 12( assuming this is max capability of the FAB
>house).
>
>By Definition ; Aspect ratio = board thickness/ min drill size.
>
>Can the Fab house able to make it drill with different board materials
>like FR4, Teflon, Rogers - is the material strength of Prepregs not
>considered?
>
>
>Thanks,
>Nagaraj
>
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
>Sent: Wednesday, February 10, 2010 9:03 PM
>To: [log in to unmask]
>Subject: Re: [TN] High Aspect ratio issues
>
>
>  Hi Nagaraj,
>Indeed, drill bit yield/ hole wall quality goes down with smaller drill
>diameters. Typically, your drill diameters are driven by the density of
>your design.
>Smaller holes are also more difficult to plate good copper into.
>Werner
>
>
>
>
>
>
>
>
>-----Original Message-----
>From: Shanmugam, Nagaraj <[log in to unmask]>
>To: [log in to unmask]
>Sent: Wed, Feb 10, 2010 5:51 am
>Subject: [TN] High Aspect ratio issues
>
>
>Technetters:
>
>I am working on the drill size selection I choose them based on
>acceptable aspect ration by Fab house.
>the reason being(to my knowledge) the drill bit yield reduces if we go
>for higher aspect ratio -
>
>Wondering what other cause prevent to go for high aspect ratio.
>
>TIA,
>Nagaraj
>
>
>
>
>______________________________________________________________________
>This email has been scanned by the MessageLabs Email Security System.
>For more information please contact helpdesk at x2960 or
>[log in to unmask]
>______________________________________________________________________
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 15.0
>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 or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at:
>http://listserv.ipc.org/archives
>Please visit IPC web site
>http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for
>additional information, or contact Keach Sasamori at [log in to unmask] or
>847-615-7100 ext.2815
>-----------------------------------------------------
>
>
>
>______________________________________________________________________
>This email has been scanned by the MessageLabs Email Security System.
>For more information please contact helpdesk at x2960 or
>[log in to unmask]
>______________________________________________________________________
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 15.0
>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 or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at:
>http://listserv.ipc.org/archives
>Please visit IPC web site
>http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
>information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
>ext.2815
>-----------------------------------------------------
>
>
>______________________________________________________________________
>This email has been scanned by the MessageLabs Email Security System.
>For more information please contact helpdesk at x2960 or [log in to unmask]
>______________________________________________________________________
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 15.0
>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 or (re-start) delivery of Technet send e-mail to 
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to 
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at: http://listserv.ipc.org/archives
>Please visit IPC web site 
>http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional 
>information, or contact Keach Sasamori at [log in to unmask] or 
>847-615-7100 ext.2815
>-----------------------------------------------------


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------