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    How to Test PCB's for Lead, RoHS


    Pronounced 'roe - haas', RoHS is the Restriction of Hazardous Substances Directive imposed on the electronics industry in Europe. Basically all it says is no company located in the EU is allowed to sell products that contain lead.

    How does this affect you? Well depends on where you live. Most companies are now following RoHS no matter where they are in the world as they don't want to lose sales in the EU.

    Now you're thinking, well no lead in all my PCB's I get, that's only a good thing, right?

    Well, only if you eat your circuit boards and/or don't like to wash your hands after working on your robots. Going RoHS compliant means it'll cost more - lead-less based solder is more expensive and new soldering equipment for higher temperatures needs to be purchased. The replacement for lead has been said to be as or more poisonous than lead itself. And lead-less solder doesn't look as nice. Lead also helps prevent harmful tin whiskers from growing and shorting your circuit.

    Anyway, this short tutorial is to show you how to determine if your board is RoHS compliant.

    RoHS Compliant Solder is Ugly
    The quickest way to tell is upon a visual inspection. RoHS compliant solder joints are ugly. They are white-ish, grainy, etc. If it doesn't shine/reflect light like a mirror, its RoHS compliant. The Axon microcontroller is RoHS compliant, have a close look if you own one.

    These two below images show the difference between lead joints (top) and RoHS compliant joints (bottom). The pictures don't really do it justice, its much more obvious if it was in your hand.

    Solder joint With Lead

    Solder joint Without Lead

    RoHS Chemical Test
    Another way you can do it is with a chemical test. You can buy a pack of Lead Check lead test swabs as shown in the boring company demonstration video:

    Basically get a swab out of the pack:

    Lead Check test swabs

    Squeeze it a few times to crack the glass inside, thereby mixing the internal chemicals:

    Lead Test Swab

    Get some of the liquid on the brush, then wipe it all over your soldered circuit board. Wait about 30 minutes, then if it turns pink like either of the below images that means you'll be having a baby.

    Its pink, Im having a lead baby!

    Its pink, Im having a lead baby!

    Well actually not a baby, it means the company that charged you $1k extra to get your board as RoHS will now try and wiggle out of paying back any money they took from you. Even though the last 10 emails and receipt all explicitly specified RoHS. I've had two companies do this to me already . . . Chinese company didn't pay a penny back, and the Indian company offered only a 10% discount off my *next* order.

    but I digress . . . rant rant rant . . .

    Point is, RoHS compliance is new to companies and they're more than likely to mess things up. Be aware of that when you select a manufacturer - find one with proven experience, and that will refund you when they mess up. Don't just go with the cheapest deal - because you'll end up paying more in the long term!

    list of PCB manufacturers and assemblers

    Anyway, the brush won't have any color (or just slight orange) if there isn't any lead on your circuit board. But of course, it can't for lead inside of your various chips, so you'll have to check datasheets for that.

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