What I would say, after seeing the picture is that it should be sent through the oven left to right not up/down. They do look to have even pulling forces on their ends as they both have the same amount of tracks exiting them. Also, are those caps? those pads are wayyyy too big looking to me, do you get cracked cap problems too? We used to have pads as big as those, when we reduced them dramatically in width placement went a lot better, they did not move around as much, Tombstoning reduced, no more cracking through pad design & we had more room on the board. Matthew Lamkin. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Taheri, Kamran Sent: Wednesday, June 08, 2005 9:38 PM To: [log in to unmask] Subject: Re: [TN] mystery tombstone cause Ben, Have you looked inside of your oven for little green monsters that might be doing this:)? Have you attached TCs to both sides of these pads to verify the thermal difference? It looks like that the pad design is reducing your placement accuracy tolerance. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Gumpert, Ben Sent: Wednesday, June 08, 2005 1:10 PM To: [log in to unmask] Subject: Re: [TN] mystery tombstone cause Bev, Yes, the direction of the tombstones on a specific board are constant relative to that board, and are irrespective of board orientation through the oven. Ben -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian Sent: Wednesday, June 08, 2005 8:40 AM To: [log in to unmask] Subject: Re: [TN] mystery tombstone cause Ben, When you say lift in different directions, do you mean in reference to the board or in reference to the axis of the oven? For instance are you saying that on a single board you can have tombstones only facing to the "top" of the board, irrespective of how you put I through the oven? Hmm, is that clear? Bev RIM -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben Sent: June 8, 2005 8:09 AM To: [log in to unmask] Subject: [TN] mystery tombstone cause Technetters, I have several SMT board styles which give me some trouble with 0306 capacitor tombstones, and through many attempts to reduce the number of these defects, I have found a condition that I can not seem to attribute a cause to. I have found that across a board, all the tombstones tend to lift in the same direction (for components in the same orientation). I have looked at the build process, but different board styles result in tombstones in different directions, so I believe the cause to be board related. I have looked at solder mask registration (misregistration occurs in various directions), power/ground plane connections by pad (changes from location to location), and solder bumps due to HASL (wicked pads have similar results), and nothing has led me to a root cause. Any ideas??? 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