Ryan, Stephen, Paul, Dan,
I appreciate you comments. Dropping local fiducials is an easy solution. I
guess it would be easy enough to just turn them off on several board types
and see if the pick & place is accurate enough to just run on globals.
Thanks again,
Jim Kittel
-----Original Message-----
From: Ryan Grant [mailto:[log in to unmask]]
Sent: Thursday, October 05, 2000 4:19 PM
To: [log in to unmask]
Subject: Re: [TN] Fiducials and HDI
Jim,
I have to agree with everyone else; local fiducials are not
necessary. We tried using them for a while, until we eventually figured out
it wasn't making a difference. Making sure the machine is properly
calibrated and strictly using CAD coordinates makes it possible to get
placement well within the tolerances of the machine using only two global
fiducials. What does make a difference is how close the global fiducials
are to the outside corners of the board.
Thanks
Ryan Grant
Advanced Technology Engineer
MCMS
(208) 898-1145
[log in to unmask]
> -----Original Message-----
> From: Jim Kittel [SMTP:[log in to unmask]]
> Sent: Thursday, October 05, 2000 8:25 AM
> To: [log in to unmask]
> Subject: [TN] Fiducials and HDI
>
> TechNetters,
>
> With so much emphasis on reducing circuit board feature sizes by use of
> micro BGA's, micro lead frames, micro vias, etc. the use of local
> fiducials
> becomes a real burden. For example, our typical fiducial is a 0.048
> circle
> with a 0.150 keep out area. This keep out area is approaching the size of
> flash memories, micro BGA's, 0402 chips, etc.
>
> Has anyone figured out a way to work around this local fiducial problem?
> Is
> anyone grouping these parts into some kind of symmetric clusters? Any
> ideas?
>
> Jim Kittel
>
> ##############################################################
> TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
> ##############################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in
> the body:
> To subscribe: SUBSCRIBE TECHNET <your full name>
> To unsubscribe: SIGNOFF TECHNET
> ##############################################################
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
> additional
> information.
> If you need assistance - contact Keach Sasamori at [log in to unmask] or
> 847-509-9700 ext.5315
> ##############################################################
----------------------------------------------------------------------------
-----
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF TECHNET
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----
---------------------------------------------------------------------------------
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF TECHNET
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
