Hello John, You should be very careful in this situation if you are speaking of cracked solder joints on SMT 0805 ceramic chip capacitors. Flex cracking under the terminations is generally regarded as one of the primary causes of failure of ceramic chips. If you can see cracks in the solder joints from board flex, those chips are certainly strongly suspect, and there is possible latent damage to other ceramic chips, where the damage may not be readily apparent. When flex stress is present, then cracks may occur under the capacitor terminations, and may be nearly invisible on the exterior surface. As a result, visual sorting cannot be relied upon to remove all damaged chips. Such cracks may result in capacitor failure through increased leakage or short circuits if they intersect opposed electrodes. Some such damage may be latent, not readily detectable during your in-house electrical or environmental testing. Ceramic chips mounted very near the edges of the board are often the ones seeing the most mechanical stress. Most SMT ceramic capacitor suppliers have recommendations and guidelines with respect to minimizing flex stress. Primary factors include part location/orientation with respect to the board edge, depanelization techniques, connector mating, and general board handling procedures/fixtures. Regards, Dick John Fahey <[log in to unmask]>@IPC.ORG> on 07/23/2001 11:10:06 AM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to John Fahey <[log in to unmask]> Sent by: TechNet <[log in to unmask]> To: [log in to unmask] cc: Subject: Re: [TN] Inspection Criteria Kathy, et al, Thank you for your detailed input. In regards to your first paragraph, I am actually looking for some good quality photos of cracked solder joints on capacitors. We are getting some cracks along the solder joint of an 0805 SMT capacitor, probably due to board flex (these capacitors are located along the board edge). Do you have any photos you could share with me so I can show our inspectors what is acceptable/not acceptable. Anything would be of help, I do not have the capabilities/equipment to take photos of these defects in house. Rgds, John John Fahey Manufacturing Engineer Echelon Corp 415 Oakmead Parkway Sunnyvale CA 94085 [log in to unmask] Phone: 408 938 5330 Fax: 408 328 3804 -----Original Message----- From: Kathy Kuhlow [mailto:[log in to unmask]] Sent: Monday, July 23, 2001 6:48 AM To: [log in to unmask] Subject: Re: [TN] Inspection Criteria I prefer to have the inspectors refresh train on the minimum requirements annually. I also am always looking for good photo's that I can put out to the inspection group of minimum acceptable. The IPC-610 Rev C has some really good photo's and I back up this with actual photo's. I make a lot of the minimum acceptable photo's and get lots of copies. I have been doing this since I first became an IPC-610 C instructor. I also include these in my outside training that I do for the local tech colleges. A couple of things that are in place here are: 1. I double check defects noted by performing secondary inspections periodically and on all first builds. 2. If a defect is questioned the person making the rejection has to prove in the IPC-610 why it is a defect exactly by clause. I have an inspector that is always looking for the mole hill. I appreciate her toughness because the processes before her know that she will be looking at everything with a fine tooth comb and they do perform better knowing that. I also like the fact that she is so thorough in her inspections and everything gets questioned. Luckily she also really understands the minimum requirements and applies the criteria correctly. She provides a tremendous amount of feedback for borderline processes. This allows us to really utilize minimum acceptable as a process improvement opportunity. Kathy --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------