Reflow parts moving

Hello: We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe...

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| Hello: | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | I have seen warpage causing a QFP208 jumping about an inch. Luckily we are able to watch the soldering in our vapourphase. Maybe a cause

Wolfgang

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| | Hello: | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | I have seen warpage causing a QFP208 jumping about an inch. | Luckily we are able to watch the soldering in our vapourphase. | Maybe a cause | | Wolfgang | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck John Thorup

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| | | Hello: | | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | | | | I have seen warpage causing a QFP208 jumping about an inch. | | Luckily we are able to watch the soldering in our vapourphase. | | Maybe a cause | | | | Wolfgang | | | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck | John Thorup | | I've had the same thing happen before. It may not be your cause, but when using HASL boards (if you indeed are), the fine pitch lands you are attaching your QFP's to may have too much solder built-up, creating a concave surface. Your leads may teeter-totter, falling to one side or the other when reflow is achieved. Your part can be off, in my experiences, up to the entire lead-width off. Just a possibility.

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| | | | Hello: | | | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | | | | | | | I have seen warpage causing a QFP208 jumping about an inch. | | | Luckily we are able to watch the soldering in our vapourphase. | | | Maybe a cause | | | | | | Wolfgang | | | | | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck | | John Thorup | | | | | I've had the same thing happen before. It may not be your cause, but when using HASL boards (if you indeed are), the fine pitch lands you are attaching your QFP's to may have too much solder built-up, creating a concave surface. Your leads may teeter-totter, falling to one side or the other when reflow is achieved. Your part can be off, in my experiences, up to the entire lead-width off. Just a possibility. | Shake and bake as presented above.

MoonMan

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| | | | | Hello: | | | | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | | | | | | | | | | I have seen warpage causing a QFP208 jumping about an inch. | | | | Luckily we are able to watch the soldering in our vapourphase. | | | | Maybe a cause | | | | | | | | Wolfgang | | | | | | | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck | | | John Thorup | | | | | | | | I've had the same thing happen before. It may not be your cause, but when using HASL boards (if you indeed are), the fine pitch lands you are attaching your QFP's to may have too much solder built-up, creating a concave surface. Your leads may teeter-totter, falling to one side or the other when reflow is achieved. Your part can be off, in my experiences, up to the entire lead-width off. Just a possibility. | | | Shake and bake as presented above. | | MoonMan |

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| | | | | | Hello: | | | | | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | | | | | | | | | | | | | I have seen warpage causing a QFP208 jumping about an inch. | | | | | Luckily we are able to watch the soldering in our vapourphase. | | | | | Maybe a cause | | | | | | | | | | Wolfgang | | | | | | | | | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck | | | | John Thorup | | | | | | | | | | | I've had the same thing happen before. It may not be your cause, but when using HASL boards (if you indeed are), the fine pitch lands you are attaching your QFP's to may have too much solder built-up, creating a concave surface. Your leads may teeter-totter, falling to one side or the other when reflow is achieved. Your part can be off, in my experiences, up to the entire lead-width off. Just a possibility. | | | | | Shake and bake as presented above. | | | | MoonMan | | | | I agree with Earl's prognosis, but one thing I would look at that won't take but a minute is the oven itself. Having 1500W's and 1700S's we have had numerous blower motors fail and this caused problems with our fine pitch and other leaded devices.

Jason

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| | | | | | | Hello: | | | | | | | We are using a Heller 1500S reflow oven to solder surface mount parts. Just within the last two weeks, the larger I.C.'s are moving while going through the oven. The parts are checked for placement before putting into the oven. When they come out the largest I.C.'s on the board have moved about half of the pad width. We have investaged many things with the oven and the screen printer but cannot find anything wrong. If any body has any ideas, I would greatly appreicate it. Thanks. Joe... | | | | | | | | | | | | | | | | | | | | I have seen warpage causing a QFP208 jumping about an inch. | | | | | | Luckily we are able to watch the soldering in our vapourphase. | | | | | | Maybe a cause | | | | | | | | | | | | Wolfgang | | | | | | | | | | | have you checked for vibration or binding in the conveyor system? is the oven still level? even air distribution? have you verified that nothing has changed in paste, profile, FAB? are all the big parts moving? the same direction? good luck | | | | | John Thorup | | | | | | | | | | | | | | I've had the same thing happen before. It may not be your cause, but when using HASL boards (if you indeed are), the fine pitch lands you are attaching your QFP's to may have too much solder built-up, creating a concave surface. Your leads may teeter-totter, falling to one side or the other when reflow is achieved. Your part can be off, in my experiences, up to the entire lead-width off. Just a possibility. | | | | | | | Shake and bake as presented above. | | | | | | MoonMan | | | | | | | | I agree with Earl's prognosis, but one thing I would look at that won't take but a minute is the oven itself. Having 1500W's and 1700S's we have had numerous blower motors fail and this caused problems with our fine pitch and other leaded devices. | | Jason |

I had the same problem while back and I found the root cause to be the oven. Thanks to our PM guys, oven's chains were so dry that they were jerking every few seconds (hard to notice)causing the parts to move during reflow!This was only causing the larger/heavier ICs to move. Good luck.

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