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Lead-free profile for big electrolytic cap

Views: 1782


Roy

#55127

Lead-free profile for big electrolytic cap | 19 June, 2008

When the component suppliers specify the cap as no more than 50sec (or even less time)above 200C, is there any way the lead-free profile window will fit if we wil have to achieve a peak temp of 230c for at least 30sec for the lead-free process? maybe only in Vapor phase?

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#55128

Lead-free profile for big electrolytic cap | 19 June, 2008

You answered your own question! Vapour phase is the way to go for this. Conventional ovens won't allow this, unless you find away to defy Physics.

That's an absurd constraint to begin with: 200C. Most Sn-Pb profiles require 205 - 210 minimum for 30-60 seconds.

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Roy

#55129

Lead-free profile for big electrolytic cap | 19 June, 2008

Thanks CK. You are right the 200C constraint is absurd, but it's the reality, and the worst is this kind of components will go through lead-free profile. Do you or any body here experiencing the same problem? any body using Vapor phase and having success? or even better, like you said, any body is trying to defy physics?

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#55130

Lead-free profile for big electrolytic cap | 19 June, 2008

If I read this right, it says 50 seconds or less above 200C. It doesn't say you cannot go above 200 C. Right? if so we do it all the time. We have some Quality gurus here that always blame our ovens for everything form a didle-I-Joe to a Dam-If-I-know, so we profile all the time.

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#55131

Lead-free profile for big electrolytic cap | 19 June, 2008

What the hell our you talking about 200 c max? I would think any nolead part is capable of going hi-er that this. I think you are looking at max temps or something that does not make sents for temps you need to reflow.

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Roy

#55133

Lead-free profile for big electrolytic cap | 19 June, 2008

<50sec above 200C is only one of the many specs, and it is the one that bothering me. Sure it can exceed 200C. The thing is, if you are using a conventional oven, how you meet the <50sec above 200C while you also need to meet the lead-free soldering requirement such as certain time above 230C.

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#55135

Lead-free profile for big electrolytic cap | 19 June, 2008

My board reaches 240 C for 45 seconds. Most of my lead free parts require 230 C for a minimum of 30 seconds.

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Roy

#55136

Lead-free profile for big electrolytic cap | 19 June, 2008

Did you ever run big electrolytic caps on your board?

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#55137

Lead-free profile for big electrolytic cap | 19 June, 2008

Sure! But they warm up slower than everything else, so it's not a big deal. You can taylor your profile around them and never exceed your 50 second threshold.

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Roy

#55141

Lead-free profile for big electrolytic cap | 19 June, 2008

So correct me if I'm wrong: you are using a conventional oven (not VP, otherwise you must have mentioned), your big electrolytic caps go through a lead-free profile, which requires 30sec minimum at 230, but your time above 200C on the caps is less than 50sec?

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#55156

Lead-free profile for big electrolytic cap | 20 June, 2008

LISTEN this is quite a soar subject to me.i have old wounds too from these capacitators and argued with the darn engineers at my old place of employment that if they only stuck to wave and through � hoel stuff, they wouldn�t be in this pickle. IF they just run these through the wave, you see the temperatures on the top don�t matter. It�s a matter of simple Psychics and science

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#55157

Lead-free profile for big electrolytic cap | 20 June, 2008

Yes.

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