OK, Steve, Bill has the best answer for your assembly problem and it should also maintain circuit integrity. Thanks, Bill....this is probably the perfect solution. Barbara - PCB Designer in Houston -----Original Message----- From: Brooks,Bill [mailto:[log in to unmask]] Sent: Thursday, January 11, 2001 11:02 AM To: 'TechNet E-Mail Forum.'; 'Barbara Burcham' Subject: RE: [TN] RF Surface mount... Hi Barbara, I have an answer to your soldering problem. Make solder 'Dam's' by creating a soldermask that ONLY has small 10 - 15 mil lines of soldermask that cross the conductor trace (at right angles) that leads away from the component pad to prevent the solder from wicking away from the pad. It will be a line barrier that will corral the solderpaste in reflow and won't affect the RF circuit like a standard soldermask would because it is so minimal. All the other circuitry can be exposed without a problem because you have restricted the flow of the solder to just the component pad. It's a good compromise, and I have used it before with great success! Good Luck with your board! I know it will work out. Bill Brooks PCB Design Engineer DATRON WORLD COMMUNICATIONS INC. 3030 Enterprise Court Vista, CA 92083 Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 mailto:[log in to unmask] IPC Designers Council, San Diego Chapter http://www.ipc.org/SanDiego/ http://home.fda.net/bbrooks/pca/pca.htm -----Original Message----- From: Barbara Burcham [mailto:[log in to unmask]] Sent: Thursday, January 11, 2001 8:10 AM To: [log in to unmask] Subject: Re: [TN] RF Surface mount... If Steve is dealing with a RF board, necking down the trace to create the solder dam could destroy the impedence and RF characteristics of the circuit. You need to: A) Talk to the client about adding the solder mask, perhaps researching why they chose not to have a mask or finding a mask material that will not degrade the circuit. B) Hand assemble Barbara -----Original Message----- From: Kathy Kuhlow [mailto:[log in to unmask]] Sent: Thursday, January 11, 2001 9:42 AM To: [log in to unmask] Subject: Re: [TN] RF Surface mount... Steve, Ina very past life we produced a product similar. We were able to control the solder running and maintain the solder tension at the pad site by having the trace necked down considerably (bare minimum width) to force and create as large a solder dam as possible. Kathy >>> [log in to unmask] 01/10/01 07:15PM >>> Hey all, We've got a job in here that's going to be a few RF assembies. It uses surface mount in the design, but the board doesn't have any soldermask at all on the surface. The last time I dealt with something such as this, and tried to print solder paste, place components, and reflow, all I wound-up with is a bunch of tomb-stones, and insufficient solder all over the board because the solder wants to flow out all along the surface layer traces, and goes where-ever it wants to go...because there's no soldermask to contain it. I'll try to post a picture of what I'm getting ready to deal with on my free-drive tomorrow... This is not high volume at all, but from past experience it's my take that we should just hand solder stuff like this...because we'll wind-up touching-up everything anyway...have any of you ever dealt with stuff like this before? -Steve Gregory- ---------------------------------------------------------------------------- ----- 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 To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------