simple doubt about reflow profile

Does this meet the SMQ230 recommended time above liquidous? Do you have any parts that cannot withstand 239 degress C? If meet SMQ230's recommended time and temps and your parts are rated for this temp, then you should be OK. The real proof is reflowing a real board and taking the time to look at it.

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Looks good at first glance. Couple of questions, though:

Time Above _____. Fill in the blank. Is Liquidous 183C (Tin-Lead) or 217C to 220C (Lead Free)?

The "soak" of 150-190, at 0.6*C per second ramp up looks good, weather it's lead or lead-free.

As for 239*C Peak... If it's Tin-Lead, that's pretty good, but I wouldn't recommend going anywhere more than that. If it's Lead-Free paste, 239*C is a little on the low-side. You should aim for 250*C to 260*C-ish.

Keep in mind, your Indium paste is very sensitive to profiles. They have near-exact requirements for things like ambient-to-peak times, etc... I would get in contact with one of their tech. support guys as well.

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Campos, This is a direct reply I recieved from Indium, (thanks to Rich Brooks), in late 2004 regarding SMQ230. I have followed these guidelines with good results using ENIG finish. Same also applies to Indium 5.1 apply to both alloys (SAC 387 and 305) 1. A ramp of 0.5 to 2.0 seconds is fine. I personally like a ramp from 1.5 to 2 sec.

2. Ramp rate can be taken anywhere.... but mainly you want to look at the ramp when the flux is doing its job. For the Indium paste, I would set a ramp rate of 100 to 200 (or 120 to 210).. somewhere in that range should provide the best results. 3. The flux activation will occur between 80 and 210 (can start a room temp)... BUT there are NO set times and temperatures. If you can shoot for a time of 60 to 100 seconds between 100 to 200 C, this should give you good results.... but this is a guideline. You can even have a long soak time of 200 seconds (bet 100 and 200) and still get good results. 4. Cool down rate is only critical from PEAK down to solid state. But you can measure from peak to 200 or even down to 150.... NOTE: The cool down rate is not as critical for Pb-free solder joints, as it was for SnPb. The grain sizes do not differ is size in the Pb-free bulk solder until you get to a cool down rate much greater than 6 degrees per second. I would attempt to get a cool down rate between 2 and 4 degrees C per second. 5. Do not worry about cooling, if you cannot get better than 2 degrees per second it is not a problem ...see question 4. The soak areas can be a lot different then what is suggested (again these are only guidelines). The only critical areas are time above liquidus and peak temperature... PEAK TEMP - attempt to stay between 232C and 240C (for best results) TIME ABOVE LIQ - attempt to stay between 60 and 85 seconds. I like to stay above liquidus for a longer time than SnPb solders because the Pb-free solders do not wet as good as SnPb (means materials do not go into solution as quickly as they do for SnPb solders)

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I here alot of guys at my place talking about cold spots in the oven. You may want to check for them in yours.

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