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BTU VIP98 Leadfree Recipe

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GEB

#41746

BTU VIP98 Leadfree Recipe | 24 May, 2006

Hi,

Can anyone recommend a leadfree recipe for a BTU VIP98 i.e. which temperatures for which zones & belt speed? I appreciate that there will be a difference from one oven to another, along with different board sizes, but would like a good starting point.

Our company have only branched out to SMT work last year so I've had to take a lot on board. The conversion to leadfree is making life more difficult. I am having difficulty achieving a profile shape like the ones shown on solder paste datasheets with a plateau at 150C then a decent ramp up to 240C. It all ends up looking like a mountain shape instead.

Help would be most appreciated.

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#41747

BTU VIP98 Leadfree Recipe | 24 May, 2006

how many zones? And what settings are you using now?

And you won't get it exactly like the data sheet, especially the cool down.

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dougs

#41749

BTU VIP98 Leadfree Recipe | 24 May, 2006

Do you really need to have that shape of profile, why not have a gradual ramp then spike? Which paste are you using?

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GEB

#41750

BTU VIP98 Leadfree Recipe | 24 May, 2006

7 zones. AIM solder SAC305.

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Chunks

#41751

BTU VIP98 Leadfree Recipe | 24 May, 2006

VIP 98, I believe that's a 7 zone if I can remember 6 years ago. Try 150, 165, 200, 235, 235 and 235 (top and bottom temps) with a belt speed of 35 inches per minute. This should get you in the ball park depending on the size of your board.

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#41755

BTU VIP98 Leadfree Recipe | 24 May, 2006

GEB, Datasheets are usually just guidelines and most App. Engineers from paste companies will tell you that as well. You don't have to "copy exact" what they say, but rather set your oven to what gets you and your type of boards the best results. Personally, I've always favored a hybrid type profile - linear ramp to start - and try to keep about 1/3 of your profile less than 150*C to preserve your activator. Alot of App. Engrs. from your paste companies will tell you that a light soak (not flat soak like they did in the '80s, but gradual) helps to remove any extra volatiles...helps in preventing flux outgassing and voids on BGA's. The trend in the late '90's was pure linear ramp, but nowadays, most paste manufacturers are now favoring that gentle soak zone, again due to BGA voiding...

If you want quick-and-dirty settings, here's what I used for my lead-free experiments on my 7-zone oven for a mixed technology 4"x6" board with 1 BGA, 0.062" FR4,bla-bla-bla Vikings: 120, 160, 165, 170, 215, 260, 260 (32" per min)....ensure you have sufficient cooling for at least a -3 deg/C cooldown!

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KEN

#41768

BTU VIP98 Leadfree Recipe | 24 May, 2006

I have 4 of these furnaces.

Give me your length, width, mass (grams) and I'll run this through our system and get you close.

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GEB

#41818

BTU VIP98 Leadfree Recipe | 26 May, 2006

Thank you - The PCB weighs 192.9g and is 314mm x 228mm. Not very densly populated.

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GEB

#41837

BTU VIP98 Leadfree Recipe | 26 May, 2006

Cheers Samir, that was a great help! I've tweaked the settings a bit to suit our PCB and it works well. Thanks again.

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