Hi Phil!

  If you have SMT on the board, you need to put fiducials on them, end of story. Most SMT automation nowdays have fiducial cameras on them to locate the PCB, and need some sort of fiducial to look at before they can start their work.

  For instance our MPM Accuflex printer needs to look at two fiducials on the board, and two fiducials on the underside of the stencil to locate the board and stencil before it prints the solder paste. We have a few customer boards that we have to build that don't have fiducials on them. I then have to resort to try and use SMT pads as fiducials. I can't tell you how much of a PIA it is to use SMT pads. I curse the designer who laid-out the board that has SMT on it without fiducials.

  If the board has SMT on it, please put fiducials on it...you'll be glad you did.

  -Steve Gregory-

Phil Nutting <[log in to unmask]> wrote:
  My disclaimer... I'm a neophyte at SMT and need some education.

Fiducials;
At what point do I need fiducials on my boards?

Is there a specific pitch or device size that will require fiducials?

Is there a "Cliff's Notes" for this?

Thermal Stitching;
We have an SMT power transistor that has about 16 thermal stitch holes
located directly under the device. The adjacent pad area is taken up by
heat sink. Is this "industry standard"?

Short of reading all the IPC standards... zzzzzzzz... oh sorry, I dozed
off there, is there a good source for coming up to speed on SMT and
board layout good standards?

Thanks in advance,

Phil Nutting

---------------------------------------------------
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
-----------------------------------------------------