Lead in solder

On Fri, 22 Feb 2008 12:11:26 -0800 (PST), with neither quill nor qualm, snipped-for-privacy@rgs.uci.edu quickly quoth:

I'd like to know where he came up with that $280B figure.

Yeah, "green" can be mighty costly, and sometimes uselessly so. (The Kyoto Protocol is one of those, with an estimated 0.07 degree C difference if every country complies.)

I think nearly all the electrical connections in a car are solderless compression fittings. If they aren't they should be. Done right it makes a better connection than solder. That means using the appropiate connector and the tooling that they were designed for. NOT those idiot "multipurpose" thingos. :-) ...lew...

Virtually NONE of the connections in/on the microprocessors and associated controllers (think Can-bus) are constructed with crimp connections. They have ciecuit boards, which are soldered. Leadfre solder is a total pain in the butt to work with, and ALL devices to be soldered with lead free NEED to be specially made for lead free solder. The problems with lead-free solder in electronics assembly are legion.

Naturally the other issues is the semiconductor material itself - It had/has a trace of a trace amount of lead and had to be out. Either copper or Aluminum micro wires either as bonding wire (was gold) to substrate.

The royal pain is right - think BGA balls and have them function with the exotic alloys needed.

Totally out of control rules and regulations that cost hundreds of millions or maybe billions ?

Martin

Mart> >

I don't know, exactly, but in my assembly business, the time taken by our assemblers to place a component on a circuit board using lead-free pure tin solder is about twice as long as with tin/lead solder. So, that may be where the amount came from. The machine placed components using a paste of tin-silver-copper takes the same amount of time. The pass through the convection oven is also about the same time.

The scary thing is what two of our customers reported in the last couple of weeks. That is a perfectly soldered lead-free component, soldered to a silver plated circuit board using tin-silver-copper solder paste, popped off the circuit board, leaving a trace of copper from the component where it had been soldered.

The actual lead-free plating on the copper component leads detached from the component.

I have read that lead-free wave soldering will always begin to dissolve the copper board trace into the molten solder. Same thing may happen with lead-free solder paste and a convection oven when the time of the paste being liquid is too long. I have not read about the component tinning/plating also causing copper problems in the component.

This happened on one component on one board out of many for two different customers. Not the same component manufacture, either.

Paul

One of many issues is the thermal expansion of component and boards. Most of the time it is close, but he tin-lead gave some stretch. This lead free is harder and causes parts to come off.

I have to debug my weather station - the outside unit has several TSSOP packages - small thin leads that Gull-wing out the sides. These traditionally spring off the pcb in massive thermal ratios, but across the country they are in failure mode and I suspect the packages should have been BGA or SSOJ with the J lead that pretends to be like a ball.

I went through a lot of engineering and stress testing - you should have seen my oven - Hot & cold oven about the size of my office - walk in - and put entire computers within - have them cycle up and down in all sorts of temps - and see if any part starts to creep or spring up.

Martin

Mart>> I'd like to know where he came up with that $280B figure.

SORRY! I keep forgeting that there all that electronic JUNK in a car. To me "automobile" wiring is the things that were in cars back in the "dim dark" years of 50s and 60s when I worked on my own vehicles. :-) ...lew...

I have read all of the responses as of now to this thread and the one contribution I will make is that you boys should not panic over these ridiculus rules and regulations that the green police are trying to invoke, because these are wars that have already been won. There have always been Ralph Naders and the like, but they are their own worst enemy. Common sense will always prevail and economics will rule supreme. Stupidity has it's just rewards. Nader killed his own carreer and so has Al Gore. Patience is a virtue. Just look what these guys do, they take undeniable observations and distort the analyisis. Fortunately, only the uninformed buy in. As an example, there are now a new class of companies that have been born just to help firms recover from ISO 9000 and all the other "Do it anyway, even if it doesn't add value" Standards. Steve

On Fri, 22 Feb 2008 20:24:21 -0800 (PST), with neither quill nor qualm, " snipped-for-privacy@coinet.com" quickly quoth:

Hand-assembled articles are surely in the minority nowadays, eh? I wonder if his figure includes the fried components due to grown tin spikes, etc.

Whoa! That's a new one. Luckily, I didn't do more than a day or two of assembly inspection in my QA years (shipping and receiving was much more fun), but that was before lead-free was politically curserect.

This does not bode well, and if it turns into a larger trend, what will the cost be to resolder all the lead-free equipment with leaded solder in the future?

Peter Huber got it right in his book _Hard Green_. The soft greenies are depriving today's and tomorrow's children of their parents' wealth and futures. Maybe the rampant idiocy in the media can be stampeded back to sanity, so the useless forms of green thinking are eliminated from the public eye.

Has anyone found stats for "lives saved by moving to lead-free solders", perchance? Any bets on the figure being low to none?

Thanks for the heads up on the possible thermal problems. We just build them as the customer requires, but very few customers even knew lead-free was required for export to Europe. So, they are still in catch-up mode! When and if we can get in on the engineering phase of a product, I will suggest we look at the larger component packaging to see if the leads or pads will allow for movement caused by expansion/ contraction.

For the edification of the other posters, most, if not all, circuit boards with surface mount components will have at least one hand-add that is either surface mount or through-hole. Also, most current production surface mount components are ONLY available lead-free. No choices.

Thanks, Paul

Gosh - I forget the name/number - but there is a lead frame metal that has the same thermal expansion coefficients as does FR4. A large Canadian Telecom required us to use it and the J leads. They had outpost (boondocks) electronics that would suffer heat of summer and cold of winter.

Martin

Mart> >> One of many issues is the thermal expansion of component and boards.