Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

# RoHS Calculation

Views: 6493

RoHS Calculation | 10 October, 2007

How do you guys calculate the total RoHSness of a part? Do you have to know the weight of the leads for instance on each part?

RoHS Calculation | 12 October, 2007

How do you measure how pregnant a woman is? A component is ROHS compliant or it is not. If a component is not compliant and is put into an otherwise compliant assembly then that assembly is no longer compliant. I doubt anyone on here does any calculations but it is based on each and every physically seperateable part of the components. If you can scrape a coating off a lead then that counts separately. Basically in the most stringently way possible. A microscopic amount of lead could make a large assembly fail if that lead is all in one seperatable piece.

RoHS Calculation | 12 October, 2007

So if I have a PCB with 2000 parts on it and one 0805 resistor has 63/37 plating on the terminations the entire assy has to be considered non lead free? That cant be right... can it?

RoHS Calculation | 12 October, 2007

> So if I have a PCB with 2000 parts on it and one > 0805 resistor has 63/37 plating on the > terminations the entire assy has to be considered > non lead free? That cant be right... can it?

Afraid so. One thing I've noticed is that now it's pretty much based on "due diligence". I think they pretty much realized how impossible it is to make sure everything is ROHS compliant. Personally I find it ironic that ROHS is to make the assemblies recycle friendly. And after googling "lead recycle" I found that lead is the most recycled substance there is. (well according to one page I found.)

RoHS Calculation | 12 October, 2007

Do you know where I can find some literature to back up that statement? Thanks for the assistance by the way...

RoHS Calculation | 12 October, 2007

To get you started you might want to look at http://en.wikipedia.org/wiki/RoHS

I think it's as good a place as any to get started. It has the basics explained in a straightforward manner. At the bottom of the page are external links they probably have much more indepth information.

RoHS Calculation | 12 October, 2007

It seems to me you need a lot of studying in this department.

RoHS Calculation | 12 October, 2007

I found the right RoHS equation: SnPb - Pb + Cu +Ag = Au

Have a great weekend lol

RoHS Calculation | 12 October, 2007

Does anyone here edit Wikipedia? I just checked and couldn't find the IPC link listed there. I still think if you ask what the OP asked then wiki is a good place to start.

Amoung other things it says the EU is helping companies comply if they have a good attitude. I think that's the only way the EU could have handle the issue.

RoHS Calculation | 12 October, 2007

And when we switch to the Occam process, we don't have to worry about solder anymore. /scarcasm

RoHS Calculation | 12 October, 2007

I get the MCV thing. I dont see it spelled out anywhere when it says each component is to be treated singularly. To me �...a maximum concentration value of 0,1 % by weight in homogeneous materials for lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) and of 0,01 % by weight in homogeneous materials for cadmium shall be tolerated.� doesn't mean if you have one component that has lead you cant use it. It means all lead frames (homogeneous) can be treated as one, all package bodies as one, all the circuit traces as one, etc..... I'm specifically looking for where it says per component.

Im basically looking for sleazy loopholes, lol...

RoHS Calculation | 12 October, 2007

If I need a lawyer I'll look you up.

To get into that kind of detail you will have to look at the legislation itself in question. And I"m sure if there were any such loophole it would be plugged by now.

But we had a customer that found something like .2% lead in a non-pop solder land. The other spots they tested were fine, it was just that one spot. Fortuneately they went leadfree long before they had to and the board didn't have to be ROHS.

Btw does anyone know how it's going for the latest round of excemption request evaluations is going? Doesn't it have a request to excempt all electronics using lead based solder?

RoHS Calculation | 12 October, 2007

The exempt request is still under consideration. Look at page 6 in following link.

RoHS Calculation | 12 October, 2007

One of the best sites for RoHS info I have ever found is http://www.pb-free.info/

The details about the separate-able-ness of a part, or the concentrations of the individual substances are not stated in the actual directive, they are stated in the guidance document for EU directives. The FAQ is found here: http://ec.europa.eu/environment/waste/pdf/faq_weee.pdf

Max concentration values are in section 2.3, as well as the definition of homogeneous, which is where the idea of all separate materials within a larger device need to be evaluated separately.

RoHS Calculation | 16 October, 2007

Does anyone know of any case that has come before court for non-compliance?

RoHS Calculation | 17 October, 2007