For .002" annular ring for 360 about the pad we look for .018" over the
drill size - both internal and external.  We have taken a few jobs in at
.016", but board size, layer count, dielectric thickness/base materials
and design geometry have an impact true position tolerance.

Jeffrey Bush
Director, Quality Assurance and Technical Support

VERMONT CIRCUITS INCORPORATED
  76 Technology Drive - POB 1890
    Brattleboro, Vermont 05302
      Voice: 802.257.4571.21 Fax: 802.257.0011
           http://www.vtcircuits.com
 
-----Original Message-----
From: Hal Winslow [mailto:[log in to unmask]] 
Sent: Tuesday, August 02, 2005 3:03 PM
To: [log in to unmask]
Subject: [TN] Required capture pad size for drilled holes?

I'm looking for what fab houses would consider to be the minimum sized
capture pad for a drilled hole in a PCB if acceptability is specified
per IPC 600 Class 3.  

 

For instance, when specifying a .010 via (+0, -.010 finished hole size)
what size pad should I design in so that you can hit the minimum .002
annular ring required for Class 3?

 

I believe that I have heard drill size plus .014 for the pad size.

 

Bonus points will be awarded if there is a difference between inner and
outer layer pad size and you detail that for me...

 

Thanks!

Hal Winslow


---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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
-----------------------------------------------------