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profile ramp starts in??

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#39822

profile ramp starts in?? | 20 February, 2006

thats the point: paste SMQ230 indium suggest a ramp between 0.5 a 1.0 degree,,but what ramp?? from 50 to 217 ,, 100 to 217,,,any idea?? i m using a ramp with .8 degree considering 50 a 217,,is teha correct????....thanks.

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#39823

profile ramp starts in?? | 20 February, 2006

#39825

profile ramp starts in?? | 20 February, 2006

From ambient, about 25C, that's to peak overall to about 230C. Dave's got the link to the SMQ 230 sheet.

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#39829

profile ramp starts in?? | 20 February, 2006

From Indium Guru, (Hi Rich). "Ramp can be taken anywhere.... but mainly you want to look at the ramp when the flux is doing it's job. For the Indium paste, I would set a ramp rate of 100 to 200 (or 120 to 210).. somewhwere in that range should provide the best results. Ramp rate of 0.5 to 2sec is fine. I prefer 1.5 to 2sec."

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Cal Kolokoy

#39831

profile ramp starts in?? | 20 February, 2006

The ramp sets the stage for flux activation, and if ramping in a linear fashion, burning off some of the volatiles, but yet preserving the activators. The ramp is also intended to preheat the SMDs to prevent thermal shock. Most solder paste data sheets are very generic with specific numbers because they want to offer their customers flexibility in profiling.

I've had experience with a couple of Indium pastes; one of their water solubles,back in my Avionics/Military manfuacturing days, and most recently the SMQ92J. With the no-clean, an Indium Apps Engineer actually recommended an ambient to peak time of 4 to 4.5 minutes to get optimal results (this is not on their data sheets). Indium also advocates the straight ramp profile where the general rule of thumb is to keep your profile at less than 150C for about 1/2 to 2/3 of the total profile duration.

You should do great with your 0.5C/s ramp rate. This tells me that the first few zone temperatures are relatively low. As long as the temperatures are greater than ambient, and gradually rising, you have got yourself a ramp, and it doesn't matter where exactly the starts. Be mindful of your ramp to peaks, don't exceed 2C/s ramp-to-peak, ensure adequate time above liquidous, and time-at-peak. These matter the most.

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