Hi Bev - my personal opinion is that a void neither enhances (i.e. acts as a crack stopper) nor degrades solder joint reliability unless you reach a threshold where the void has physically reduced the overall solder joint area thus making the distance a crack has to progress to fail a solder joint critically short. There are a number of published industry reports that would support that hypothesis. I would follow the logic path that George does for his RF applications - what size or total amount of voiding impacts the functionality of the product application. In your case, you are looking for a solder joint area for a variety of component styles that can withstand the rigors of dropping a hand held device. The drop test idea that Ioan proposed could be a way to derive a data set. And you avoid (yes, that was an intentional pun) having to make voids by creating solder joints of different areas for testing. And it would be a really good co-op project! Good Luck. Dave Bev Christian <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 05/03/2010 07:24 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Bev Christian <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Question about Voids in Solder Joints Thanks, George. Most detailed answer yet. At Nortel we never had a void spec for leaded components either. And, as I think I have said on TechNet before, we would find many joints after pull testing or cross-sectioning that looked like Swiss cheese, but we never had field failures as a result. BUT we were manly concerned about the possibility of failures due to thermal cycling. Now I worked for a company where the main concern is customers dropping their product onto hard edges. We do a lot of work to try and design and build products to survive multiple drops in different orientations, but occasionally a switch is going to come down on a pointed rock or a customer is going to rip a charging cable out of a connector at a 45 degree angle (yikes). These are the things I am talking about. I was leaning towards 25% for leaded components, so you and I are in the same ball park, George. Others have suggested a higher number, but without some encouraging words in that direction from fellow TechNetters, I ain't goin' there. Bev RIM -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M. Sent: Monday, May 03, 2010 5:57 PM To: [log in to unmask] Subject: Re: [TN] Question about Voids in Solder Joints Bev, We're in a similar position to Dave Hillman. We basically follow IPC standards (where there are standards). We do not have a company standard for leaded components. A couple of small voids is okay, more or large voids are not. Having said that you'll probably ask how many is a couple and what is small and what is large. We don't have a really good answer. Since we do a lot of RF power component work we've adopted a voiding specification that has worked well for IC packages. They typically use a criteria of total die attach voids <20% with no single void >5% is okay. We don't actually measure voids in leaded devices but if we were to see 20% voiding in a leaded component solder joint we'd be concerned. Regards, George George M. Wenger Senior Principal FMA / Reliability Engineer Andrew Corporation - Wireless Network Solutions 40 Technology Drive, Warren, NJ 07059 (908) 546-4531 Office (732) 309-8964 Mobile E-mail: [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian Sent: Monday, May 03, 2010 3:48 PM To: [log in to unmask] Subject: [TN] Question about Voids in Solder Joints TechNetters, I was thinking about just putting "Voiding" as the e-mail title, but I contemplated what I might get in responses and amended my title accordingly. My question is the following: do any of your companies have upper limits on the amount of voiding in SMT solder joints of components that customers have access to - like connectors and switches? These of course are leaded components. I am not talking about Pb, but the form of the interconnect between the component body and the board. If so, are you willing and can you share? Bev RIM --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful. ______________________________________________________________________ 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 ----------------------------------------------------- ______________________________________________________________________ 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 ----------------------------------------------------- ______________________________________________________________________ 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 ----------------------------------------------------- ______________________________________________________________________ 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 -----------------------------------------------------