Bingo! Boy that brings back memories of why radius corners didn't work. It reeked havoc on the CAD database and resultant CAM files. We put a lot of work into "hands off" db and the manual intervention was way to much and subject to error. It also kept us away from automated footprint generation, rippled into ease of center part, also kept us out of a couple of nice check cycles regarding searches for odd integers.
----- Original Message -----
From: Ahne Oosterhof<mailto:[log in to unmask]>
To: [log in to unmask]<mailto:[log in to unmask]>
Sent: Tuesday, July 27, 2010 1:20 PM
Subject: Re: [TN] 0201 footprint requirements
Hi Bill and Hi IPC,
From a software point of view "oblongs" are more pleasant than rounded
rectangles. The reason being is that oblongs exist in the Gerber language
and rounded rectangles do not. Most software can deal with rounded
rectangles by combining in a macro four straight lines and four 90 degree
arcs. But some software uses several short straight vectors to make up those
arcs which may causes subsequent problems.
Regards,
Ahne.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brooks, Bill
Sent: Tuesday, July 27, 2010 09:43
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] 0201 footprint requirements
I recently attended a presentation by Tom Hausherr where he indicated
that the IPC was leaning towards the use of "rounded rectangle pads" for
surface mount... I think this is what he means by 'radius lands'. This
means they remove the sharp corners of the rectangle lands 'rounding'
them...
Bill Brooks | Datron World Communications, Inc.
PCB Designer/Engineer | Office: 760-602-7004| Fax: 760-597-3777 |
[log in to unmask]<mailto:[log in to unmask]>
1808 Aston Avenue, Suite 230, Carlsbad, CA 92008 | www.dtwc.com<http://www.dtwc.com/>
Performance You Require. Value You ExpectTM
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brad Saunders
Sent: Monday, July 26, 2010 7:21 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] 0201 footprint requirements
We had found that no square pads was a good thing. With radii corners
on all lands we saw much, much less de-wetting, stencils cleaned easier,
less slump, components jockeyed better, but alas there were issues in
database compatibility and repeatability especially between fabricators
and stencil suppliers.
We turned the corner on the radius and stayed square. you dig?
Brad
Sorry for the late response.
----- Original Message -----
From: Werner Engelmaier<mailto:[log in to unmask]<mailto:[log in to unmask]>>
To: [log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>
Sent: Tuesday, July 13, 2010 4:07 PM
Subject: Re: [TN] 0201 footprint requirements
Hi Brad,
When you say 'radius lands'-what exactly do you mean? Can you share
your experiences?
Werner
-----Original Message-----
From: Brad Saunders <[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>>
To: [log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>
Sent: Tue, Jul 13, 2010 3:58 pm
Subject: Re: [TN] 0201 footprint requirements
Howdy Bill,
I was delighted to see Werner's answer on this question. I had done
very
exhaustive reliability study on solder joint reliability specifically
related to
footprint design and we concluded exactly what Werner was able to say
so
eloquently. I found later the footprint also was a political platform
and to
satisfy a consensus I constructed a formula that would give a bit of
pad to the
sides and ends. I knew it would not subtract from reliability and -so
long as
it didn't get to big I was OK- it did allow me to round off pad sizes
which is
very nice, also I was able to manipulate center spacing which
additional
benefits.
But don't grow that length under your parts... and don't get me going
on radius
lands verses square.
Boston Brad
----- Original Message -----
From: Brooks, Bill<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>>
To:
[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:T<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]:T>
[log in to unmask]<mailto:[log in to unmask]>>>
Sent: Wednesday, July 07, 2010 2:37 PM
Subject: [TN] 0201 footprint requirements
I am looking for some assistance with the pad geometries for 0201
caps
and resistors...
Is there or is there not an industry consensus on what the optimum
pad
geometry should be for them?
What I am hearing from our assembly houses differs greatly from what
is
published in IPC-7351 and the land pattern tool from PCB Matrix.
Is the max material condition footprint actually a recipe for
tombstoning?
What have you folks seen? What do you recommend?
Bill Brooks | Datron World Communications, Inc.
PCB Designer/Engineer | Office: 760-602-7004| Fax: 760-597-3777 |
[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]>
o:[log in to unmask]>>
1808 Aston Avenue, Suite 230, Carlsbad, CA 92008 |
www.dtwc.com<http://www.dtwc.com/<http://www.dtwc.com%3chttp//www.dtwc.c<http://www.dtwc.com%3chttp//www.dtwc.com/%3Chttp://www.dtwc.com%3chttp//www.dtwc.c>
om/>>
Performance You Require. Value You ExpectTM
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security
System.
For more information please contact helpdesk at x2960 or
[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]>
o:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]>
o:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]>
o:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]>
o:[log in to unmask]>>: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives<http://listserv.ipc.org/archives<http:/<http://listserv.ipc.org/archives%3Chttp://listserv.ipc.org/archives%3Chttp:/>
/listserv.ipc.org/archives%3Chttp://listserv.ipc.org/archives>>
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont<http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont>
entpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3<http://www.ipc.org/contentpage.asp?Pageid=4.3>.
16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16>>>
for additional information, or contact Keach Sasamori at
[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:sasa<mailto:[log in to unmask]:[log in to unmask]:[log in to unmask]:sasa>
[log in to unmask]<mailto:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives<http://listserv.ipc.org/archives<http://listserv.ipc.org/archives%3Chttp://listserv.ipc.org/archives>>
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont<http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont>
entpage.asp?Pageid=4.3.16> for
additional information, or contact Keach Sasamori at
[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives<http://listserv.ipc.org/archives<http://listserv.ipc.org/archives%3Chttp://listserv.ipc.org/archives>>
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont<http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/cont>
entpage.asp?Pageid=4.3.16> for additional information, or contact Keach
Sasamori at [log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives<http://listserv.ipc.org/archives>
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional
information, or contact Keach Sasamori at [log in to unmask]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives>
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16>
for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[log in to unmask]>: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives>
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[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
-----------------------------------------------------
|
