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  1. #1
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    Reflowing SMD PCBs with suspect dry-jointed components on them?

    Hello,

    We have some all-SMD, FR4 PCBs which comprise LEDs and Driver components, or some PCBs which have just driver components. These PCBs are either double sided or 4 layer. They are 1.6mm in thickness. The components range from D2PAK FETs down to 0402 resistors, and 4mm by 4mm SMD LEDs.

    We are sometimes finding that these PCBs, when delivered to us, don't work because of dry-jointed LEDs or other components.

    We find this out because we can often make PCBs work by simply 'dunking' on/near the component pads with a big , wetted soldering iron.

    However, we really need a better way to reflow these SMD components. Do you believe a hot-plate would be best?, or some kind of little SMD oven?, or an IR oven?
    Sometimes the dry-jointed components have connection to a thermal copper pour on the PCB bottom. -But sometimes this is not the case.

    We are actually wondering if the best & quickest way of doing it could be to simply put the PCB on a cheap hot-plate and waft over the suspect dry-joint components with a "gas gun" soldering tool?..(blowing scorching hot air on the suspect components)

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  2. #2
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    Re: Reflowing SMD PCBs with suspect dry-jointed components on them?

    Get a better assembler.


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  3. #3
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    Re: Reflowing SMD PCBs with suspect dry-jointed components on them?

    With all these cold solder joints you've described, they probably don't have anyone working there that knows how to setup the reflow to have the proper temp profile or how to adjust the profile for your board.

    Or you do like one company I worked for...
    You have the contract manufacturer, purchase parts, assemble, test, and you only buy finished working boards from them. When the assembly house has a bone pile up to the ceiling and they are loosing money in building your board, they will start working hard at fixing their process.


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