Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMT Backward Compability


SMT Backward Compability | 6 July, 2005

We start to get mixed component leaded and lead-free, we still using leaded solder paste in the SMT process. Do you see this a problem to use leaded process 179 deg celsuis temperature reflow on RoHS compatible lead-free components with same specification.

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SMT Backward Compability | 6 July, 2005


If the components are caps and resistors etc there should not be much problems. I would say everyone at this stage has a mixture of leadfree and lead components. The problem really starts when you are running the likes of Leadfree BGA where the eutectic is 217 deg with a peak of 235-245 deg. Although in saying that I has to run a leadfree microbga with lead paste on a prototype and it worked fine with a peak of 230 deg.

You will just have to keep an eye on leadfree parts that come in and see how they go through the process. At the end of the day if the part is only available in leadfree you have no choice but to use it....

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SMT Backward Compability | 6 July, 2005


Thanks for your input, forgot to inform that there is none BGA on the PCB. I also discovered that there was another topic related mixed component that give me support enough. Will inform my supplier to perform the process in the SMT line and not do the lead-free component by hand soldering as they suggested.

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