BGA Profile

I am profiling a BGA for the first time and I am seeing temperature flucuations on the ramp and cool down from the thermocouple I have placed through the pcb and under the component. I am using a 5 zone convection oven.Any suggestions on the ploblem are welcome. Thanks Richard.

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| I am profiling a BGA for the first time and I am seeing temperature flucuations on the ramp and cool down from the thermocouple I have placed through the pcb and under the component. I am using a 5 zone convection oven.Any suggestions on the ploblem are welcome. Thanks Richard. | Rich, Is the thermocouple in a sphere. This is critical. It sounds like your thermocouple is probably making intermittent contact with a sphere.

Regards, Justin

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| I am profiling a BGA for the first time and I am seeing temperature flucuations on the ramp and cool down from the thermocouple I have placed through the pcb and under the component. I am using a 5 zone convection oven.Any suggestions on the ploblem are welcome. Thanks Richard. |

Your thermocouple has most likely come loose. This results in 'spikes' that you see throughout the profile. Make sure that when you put the thermocouple on, that it is encased in enough high-temp solder that it will not reflow. If you attach the tc with only a small amount of high-temp, the eutectic solder will combine with the high-temp and effectively lower the melting point thus allowing the tc to break free. Hope this helps.

ML

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| I am profiling a BGA for the first time and I am seeing temperature flucuations on the ramp and cool down from the thermocouple I have placed through the pcb and under the component. I am using a 5 zone convection oven.Any suggestions on the ploblem are welcome. Thanks Richard. | Richard: Mike and Justin offer good advice. Chrys gave good advice on attaching thermocouples on the following occasions:

Posted by Chrys on November 30, 1998 Posted by Chrys on December 17, 1998

Check it out in the archives.

TTYL

Dave F

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I second Dave's encouragement to use the archives. It's a wealth of info and the search engine usually get's me what I want the first time.

By the way, Richard, are you soldering your thermocouple to a ball on the BGA with hi-temp solder? It'd help keep the bead from "bouncing" around and not reading the real temp. on the balls.

Joe.

| | I am profiling a BGA for the first time and I am seeing temperature flucuations on the ramp and cool down from the thermocouple I have placed through the pcb and under the component. I am using a 5 zone convection oven.Any suggestions on the ploblem are welcome. Thanks Richard. | | | Richard: Mike and Justin offer good advice. Chrys gave good advice on attaching thermocouples on the following occasions: | | Posted by Chrys on November 30, 1998 | Posted by Chrys on December 17, 1998 | | Check it out in the archives. | | TTYL | | Dave F |

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