Sorry, Jason, had DFM in mind. Have seen all sorts of tuning, from Wrigleys gum to scalpel cuts to bending, stacking, glueing, swearing and using earwax. Agree, mysticism an ingredient, but it's possible to rethink. We now make microwave modules with amazing lot of RF stuff in, automounted and no tuning. But it took some time and the cost was little amazing too.
Ingemar
-----Original Message-----
From: Jason Lineback [mailto:[log in to unmask]]
Sent: den 16 augusti 2002 16:07
To: [log in to unmask]
Subject: Re: [TN] Solder fillet requirement
I have to disagree with Peter here. In a perfect world, on a perfect design, maybe Peter is right. In the real world working with and tuning a RF circuit is all Black Magic. Some days the same tuning method used on one assembly has the exact opposite effect on the next assembly.
I worked for a RF attenuator manufacturer for several years. A lot of times the first thing we did when tuning was to put solder on the end caps of capacitors. This in effect would negate the inductance that was inherent in the transmission path.
BTW - Ericsson was one of their bigger customers.
Jason Lineback
Manufacturing Engineer
diversifiedsystems, inc.
-----Original Message-----
From: Ingemar Hernefjord (EMW)
[mailto:[log in to unmask]]
Sent: Friday, August 16, 2002 3:08 AM
To: [log in to unmask]
Subject: Re: [TN] Solder fillet requirement
Peter,
fat fillets do not improve RF properties, not one single 'dB'. Generally spoken, the problem is opposite: to get everything as 'planar' as possible. One day, porcelain caps will be superseded by planar, built-in caps (today porcelain have some outstanding properties that are hard to obtain with other components). Today our caps have solder joints just under the terminal, just wetting around the corner for inspection purpose, but not climbing high as was custom in earlier days. Too fat fillets are dangerous in mechanical point of view, and most cap manufacturers give clear advice about how the good joint should look like. When we changed to modern and slim joints, some old dogs grunted, but today our solder quality handbooks have no more images on fat joints. I ought to demonstrate the profession of my own company, but I must admit that, personally, I open a jap product when I like to see perfection, e.g. a J.C or S..y VCR..(enough camouflaged?)...
admiration of jap products, am I banned now by the TechNet generals ?
Regards
Ingemar Hernefjord
Ericsson Microwave Systems
-----Original Message-----
From: Peter Lee [mailto:[log in to unmask]]
Sent: den 9 augusti 2002 08:51
To: [log in to unmask]
Subject: [TN] Solder fillet requirement
Technet,
One of our customers is requesting 75% solder fillet height on all the
SMT Porcelain capacitors (0805 package size with taller profile) used
for a RF application. We told them based on our experience that the
excess paste volume (and wetting) can not be achieved by our SMT stencil
process. IPC only requires 25% for class 2 products. But they are now
specifying hand soldering these components.
Can anyone see any reason for doing this? I am prepared to go back to
our customer to convince them otherwise (reasons such as extra labour,
process inefficiency, solder joint reliability etc.)
Rgds,
Peter
---------------------------------------------------------------------------------
Technet Mail List provided as a free 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/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 1.8e
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/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 1.8e
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/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 1.8e
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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
