Hi Ilkka, It may be the problem is related to component solderability since the PCB seems to have good wetting but the components break-off. This may cause marginal wetting making a fragile joint or "Toumbstoning" (where the chip device flips from vertical to horizontal during reflow). These problems can be difficult to trouble-shoot since the interaction of component solderability (both PCB or component), soldering materials and soldering parameters. Assuming SMD pads are correctly sized, chip components should "self-center" (align) during reflow. If there are solderability (wetting force) problems or the reflow profile is not well controlled, the chips can rotate or vertically lift due to inbalance of the wetting force (side to side). If you frefer to IPC workmanship standards, you should find decriptions and photos of skewed (rotated) and "Toumbstone) components for comparison. Your supplier should as their inspectors if they have sen this, it might help them to trouble-shoot the problem. Since no glue is used we can eliminate glue contamination on the pads. Since they are soldered top side we can eliminate adhesion problems from bottom side. If they have AOI and it did not find mis-placements or missing placements we can sliminate pacement of reel handling problems since either would result in a mis-placed or missing component. The Reel Mishandling could result in components coming loose from the tape (if used) or being lost. High speed shooters generally alarm if this is the case but I just wanted to help you consider the possibilites. Regards, C.B. Katzko, CTO Meadville Group e-mail [log in to unmask] tel +86 21 3774 7528 fax +86 21 3774 7590 mobile +86 13817362590 +++ Please note new tel & fax numbers. +++ "Ilkka Lehtinen" <[log in to unmask]> 2008-01-14 14:10 请答复 给 <[log in to unmask]> 收件人 "'Chris Katzko'" <[log in to unmask]> 抄送 <[log in to unmask]> 主题 RE: ´ð¸´: [TGA] SMD components cracking off Hi Chris, 1. The solder pads are look like that the solder has not attached to the component. There is solder on the pads and you can clearly see the component has been there correctly but for some reason it is not anymore. The component sometimes is broken off i.e. there sometimes are parts of components left but usually there is only the solder left. Like somebody would have removed the component by using pliers (this naturally is not the case here). 2. Components are SMD components as I said and maybe you could find the reason by checking manufacturing dates. Problem with this route is that this problem has been there many months and the contract manufacturer does not have big stocks. Also PCB solderability does not seem to be problem according to the soldering results. 3. Manufacturing process is very normal: paste printing, SMD assembly, AOI checking, THD assembly (manual), wave soldering, testing and packing. The missing components are SMD components assembled by assembling machine. In AOI phase the components are still there without any defect codes. 4. The components are on the top side of the PCB and glue is not considered needed in our products. 5. I’m not aware about our contract manufacturer’s machine adjustment, servicing or cleaning procedure or policies. Currently our PCB’s have only one fiducial mark even if adding another has started to some of the products. But AOI, as I said, does not find misplacements. What is SMD component reel mishandling, could you be more specific about what you mean? Thanks and BR, Ilkka Lehtinen From: Chris Katzko [mailto:[log in to unmask]] Sent: 11 January 2008 17:27 To: [log in to unmask] Cc: [log in to unmask] Subject: 答复: [TGA] SMD components cracking off Hi Ilkka - Since the root cause is still unclear, can you provide some information about the failure mode? For example: 1. What is the appearance of the solder pads in the missing component locations? Is there evidence the component was broken off (ie, a solder joint was formed and then fractured) or any indication of solderability issues (ie, the pads show de-wetting/non-wetting)? Keep in mind solderability problems could be due to component issues as well as PCB, but we examine the evidence we have. 2. If a component solderability issue is suspected, you might try tracing the failures to date codes, but with passives used in bulk that might be difficult. 3. What type and sequence of soldering processes are used? At what step are the missing components soldered? 4. Are the components normally glued when placed? Any evidence of problems? 5. Is missed placement a possibility? In other words, does the assembly equipment or downstream AOI (if used) detect a missed placement? An indication of this would be perfectly solderd pads without components. Missing is possible if the placement mechanisms are not properly adjusted, dirty or worn. I'm assuming they are placed with a high-speed chip shooter, vacuum suction force and timing may be an issue. Another possiblity is if the tape reels are mishandled before loading or by machine maslfunction. TGAsia has many experienced assembly engineers, if you provide more information, perhaps they can help. Regards, C.B. Katzko, CTO Meadville Group e-mail [log in to unmask] tel +86 21 3774 7528 fax +86 21 3774 7590 mobile +86 13817362590 +++ Please note new tel & fax numbers. +++ Ilkka Lehtinen <[log in to unmask]> 发件人: TGAsia <[log in to unmask]> 2008-01-11 16:54 请答复 给 [log in to unmask] 收件人 [log in to unmask] 抄送 主题 [TGA] SMD components cracking off Hi, I'm Mr. Ilkka Lehtinen, a Quality Manager in Teleste Corporation's (a Finnish company) manufacturing company in Suzhou, China. It's honor for me also to join this discussion forum. Our contract manufacturer has a problem they cannot solve themselves with SMD components: every now and then we find boards that have one or two SMD capacitors, resistors or inductors fallen off the board somewhere during the manufacturing process. The resistors and capacitors are 5-sided termination components and inductors are bottom only termination components. Normal stuff. The size is 0603. The problem is not location specific so it's not caused by some mishandling or that some areas are somehow prone to this kind of behavior. I'm out of glues. Has anybody faced this kind of problem or have any idea? Thanks in advance, Ilkka Lehtinen Quality Manager Teleste (Suzhou)