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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


SMT REWORK

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dougs

#40853

SMT REWORK | 6 April, 2006

Hi,

We have just purchased a new rework station, i'm looking for tips to get the best quality rework possible. Currently when we are replacing a SMT component we take off the old one clean the pads with solder braid then IPA, re-tin the pads then place the component and apply heat. This i'd think would have consequences when doing lead free rework due to copper dissolution, should we be applying solder paste to the pads rather than tinning them, if so how do you all do your rework, any tips would be much appreciated.

thanks

Dougs

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RDR

#40854

SMT REWORK | 6 April, 2006

We do what you currently do for lead free rework. Why are you worried about copper dissolution? I think I'm missing something

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dougs

#40855

SMT REWORK | 6 April, 2006

maybe i'm missing something, i though copper dissolution is a major concern when reworking parts from a lead free process, whats the forums opinion?

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#40856

SMT REWORK | 6 April, 2006

Copper dissolution is a major issue in lead-free soldering, but only when you use OSP boards. Nickel based plating eliminates the problem.

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Marla Johnson

#40857

SMT REWORK | 6 April, 2006

Hello Dougs: Have you tried stenciling solder paste to the BGA part itself. You will find this most helpful for your heat transfer and attachment integrity of the component in a Pb free process.

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dougs

#40873

SMT REWORK | 7 April, 2006

Thats something i've been thinking about, what about other types of SMT component, QFP, QFN, etc etc?? What is everyone out there doing?

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#40877

SMT REWORK | 7 April, 2006

When reworking a BGA, we apply paste, inspect alignement with a camera and then proceed with the temperature profile. For the majority of the other components easily side accessible we do them by hand soldering.

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Ken

#41030

SMT REWORK | 18 April, 2006

Dougs,

if you are looking to do some training on SMT Rework and Troubleshooting, you may want to consider the following:

http://cgi.ebay.com/SMT-SMD-SURFACE-MOUNT-REWORK-PRACTICE-PROJECT-KIT_W0QQitemZ7502678211QQcategoryZ4663QQcmdZViewItem

Good luck,

Ken

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