Hi Jeff: I am interested in seeing the data sheet. Regards, Ramon -----Original Message----- From: Jeff Brown [mailto:[log in to unmask]] Sent: Tuesday, November 22, 2005 9:58 PM To: Dehoyos, Ramon Subject: RE: [TN] Unusual soldering challenge Hi Ramon, Thanks for your question. There is no plating to be carried out. The component is to be soldered onto pads on a larger board in the usual way, except that in this case, the base of the component consists of the 1" x 0.6" piece of fibreglass (acting as a carrier for an IC) with copper pads underneath it. A little like mounting a BGA except that instead of having solder balls there is just paste, meaning that there is very little separation between the component and the large board. I hope that's a bit clearer. Regards, Jeff -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Wednesday, 23 November 2005 1:01 AM To: [log in to unmask] Subject: Re: [TN] Unusual soldering challenge Hi Jeff: I am not fully understanding. There is a small 1" X 0.6" board that has an exposed copper pad and four lands for a four leaded surface component. The process consists of plating the pad at the same time reflowing the leads of the part to the lands to mount it to the board. If that is what is being done, can the pad come already plated from the board vendor or cover with solder mask? I am just asking. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ivanoe Pedruzzi Sent: Tuesday, November 22, 2005 3:56 AM To: [log in to unmask] Subject: Re: [TN] Unusual soldering challenge Jeff, a grid in the aperture of a stencil of that sort is, in my experience, a good advice. This is the only way to keep the part seated in its position when reflowing. If not divided in smaller parts, the surface tension of the liquid in that area is strong enough to re-align the part on the center of the stenciled paste. Besides shifting, you can't even prevent the component from rotating. I haven't ever experienced any problem with flux entrapped nor with boiling. A sort of "tic-tac-toe" grid is what I was used to have in the aperture. have a good one, Ivan Il giorno 22/nov/05, alle ore 06:46, Jeff Brown ha scritto: > Hi Everyone, > > We have a problem with a fairly unique component that requires > soldering to a PCB. I'm really hoping that someone has seen this > before as it looking really awkward. > > The component is mounted on a piece of fiberglass about 25mm x 16mm. > The footprint consists of a ground pad which takes up 95% of the area, > and four signal pads with 0.5mm clearance from the ground pad. > > The manufacturer recommends a grid of stenciled paste for the ground > pad due to the large area, but we are concerned that if the paste > melts from the outside edges in, then it will at a minimum result in > flux entrapment, and at worst, the trapped flux will boil and lift the > component, or move the molten solder causing shorts to the signal > pads. > > I imagine that even if we used solid paste pattern that this would > probably only make the problem worse. > > Or are we just being overly pessimistic? > > Any thoughts on options would be gratefully received... Currently > wondering about the possibility of applying BGA balls to the package > so that there is some clearance between the board and the component. > > If anyone is interested, I can send the component datasheet to them > directly. > > Thank you all in advance > > Jeff Brown and Josh Vear > EOS Space Systems > > --------------------------------------------------- > 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------