"Lead-Free" - The International Environmental Boondoggle

In honor of today being the unofficial "L day" I'm posting this item that came to my attention last Monday.

In case you wonder what might have happened if the Kyoto Protocol had been adopted and implemented world wide, consider what happened when the EU unilaterally determined that the lead in solder used to produce electronic devices is a "hazardous substance" and mandated its elimination from all products marketed in Europe by the July 1, 2006.

On Monday a colleague emailed several of us a list of issues related to lead-free electronics manufacturing that was provided to him by our assembly vendor. Before reading the attachment I had no idea just how disruptive this lead-free process business is. Why would we voluntarily evolve into a process that is less reliable, more expensive, fraught with extra hoops to jump through and, by the way, is WORSE for the environment?

This all stems from an EU directive called the "Reduction of Hazardous Substances" directive, or "RoHS" adopted January 27, 2003. Here's what I found when I investigated.

From “The ultimate in fatuity” on EU Referendum blog (based in UK):

According to the authors, "The study presents extensive data that show that heavy metal concentrations in leachate and landfill gas are generally far below the limits that have been established to protect human health and the environment."

By then, it was too late – the "train had left the station" and the momentum for new legislation was too great. But, by 2005, the US Environmental Protection Agency had got its act together and produced a 472-page report, assessing the full, life-cycle environmental impact of banning lead solder.

From this work, it emerged that when the impact of mining and refining substitutes was taken in to account, the higher energy consumption in using the lead-free solders, which require higher temperatures, and all the other issues were factored in, the banning of lead – far from having a positive impact on the environment (and worker health) – actually had a significant negative impact. Amazingly, though, this work had never been done by the EU and the legislation was, by then, already in place.

And then there are the long-term reliability concerns. Also from the EU Referendum blog:

On the basis of this charade, proprietors of firms not obeying this cretinous law can face unlimited fines and imprisonment yet, worryingly, there are still many serious doubts about the reliability and suitability of lead solder substitutes, so much so that military equipment has been exempted.

And this isn’t just some mad right-wing anti-environment rant. In the comments on the blog is a reference to this article from the St. Louis Post-Dispatch quoting a Canadian environmental scientist who doesn’t support lead-free:

But not all lead is the same. Lead in paint and gasoline is easily absorbed into human cells. Lead in metallic forms such as solder is not.

In addition, evidence indicates that soldered lead, once inside landfills, does not leach out into drinking water, said Laura Turbini, a materials science faculty member at the University of Toronto.

Turbini has studied and tried to help diminish the impact of industry on the environment since the days of CFCs in refrigerators. Her presentations declare "humanity is off course" environmentally. She also strongly advocates recycling electronics. But she does not support lead-free.

"From cradle to grave," Turbini said, "lead-free soldering is not better for the environment." Replacements for lead solder cost more to mine and require more energy to use and produce.

As for “state mandated deadlines for compliance” are we sure there are, or will be, any? Consider this, also from the news article:

No U.S. firm is legally bound to use lead-free solder. Only California has any restrictions on lead, and no federal laws are pending. But not conforming to European standards means giving up a lucrative market, and potentially that of China and Japan. China is expected to announce a restriction policy soon.

But since our market is exclusively the U.S. and not even Canada, much less Europe or East Asia, it appears that we should do everything possible to avoid lead-free like the plague. The problem with this strategy is that component manufacturers, forced to comply with RoHS by customers who market products in Europe and eager to avoid the added cost of parallel leaded and lead-free product lines, are gradually discontinuing the leaded components.

And so we have a world-wide economic and environmental travesty all because one man, the EU minister of state for energy, Malcolm Wicks, signed the final RoHS document declaring, "I have read the regulatory impact assessment and am satisfied the benefits justify the costs."

And angry-left nutjobs worry that we are sliding into a monarchy!

Take the disruptions, cost increases and environmental unintended consequences of this and multiply them by ten, or even a hundred, and you'll have an idea of what Kyoto could have wrought.

(Click "Continue Reading" to see the list of issues related to lead-free soldering processes.)

Company x’s Lead – Free Process Issues
1. Lead-Free assemblies are less reliable: Company x says we should expect 30% more solder joint failures in a lead-free process.
a. Through-hole joints will not be filled up to IPC-Level 1, but should conform to the IPC Level-2 soldering standard.
b. Our QA group should expect to see less flow and poorer overall solder joints. These joints are more susceptible to mechanical stress and vibration.
c. Tin solder will “grow” thin shards (whiskers) over time. These whiskers can eventually short higher density designs
2. Lead-Free assembly processes cost more: You will see why as you read the issues here.
3. Gold PCBs: Company x prefers Immersion Gold on top of Nickel. Company x is having issues soldering to our Immersion Silver boards:
a. The silver oxidizes fairly quickly, so the PCB shelf life isn’t very long with silver
b. Company x uses a lot of cardboard, which is one of silver’s worst enemies. They try to be careful, but find they still set a lot of bare boards directly on cardboard.
c. The flux isn’t powerful enough to break down the silver oxide when soldered
d. The lead-free solder doesn’t adhere well to silver even when it is not oxidized
Company x prefers 180-200 micro-inches of Nickel over the copper and 3-8 micro-inches of Gold over the Nickel. This finish has a good shelf life, doesn’t react with materials used in handling and storage, and readily adheres to the tin solder.
It may cost us more per board up-front, but Company x is saying due to the soldering issues, it saves us money on the overall assembly.
4. High-Temp FR-4: Most assembly houses request a higher temperature rated FR-4 material for lead-free processing. Company x hasn’t seen any PCB issues due to the higher oven temperatures yet. However, de-laminating and warping may occur, especially on PCB areas with few parts. Data Circuits/Merix hasn’t charged us more for this material in the past, so I suggest we start using it on all of our PCBs.
5. High-Temp Parts: Company x has settled on 245 C as their lead-free oven temperature. Many aluminum electrolytic capacitors and connectors will be destroyed at these temperatures. I have found that many ROHS rated aluminum electrolytic capacitors aren’t specified to handle this temperature and are rated to only 235-240 C, especially the larger caps. All of the parts we want to run through a lead-free reflow process must handle at least 245 C, although 260 C is preferable, but hard to obtain in the larger caps. Due to the higher oven temperatures required for lead-free reflow, we must re-evaluate each part in the assemblies we want to become lead-free.
6. Hand soldering is difficult: Lead-free solder not only requires a higher temperature to flow properly, but it doesn’t wet, flow, or adhere as well as lead based solder. Interestingly, soldering iron tips only last 8-10 hours due to the aggressive tin reaction to the tips themselves. To increase the soldering temperature, the soldering iron tips are larger which makes it more difficult to solder small parts. Company x has asked us to change the following in our designs:
a. Increase annular rings around hand-soldered holes or anything we will want to ever be re-worked. 15-20 mil per side is desirable. Use elliptical holes for finer-pitch parts.
b. Try to always use thermal rings to connect pads (SMT and thru-hole) to ground planes and copper pours. The pads must get hotter for good reflow and direct plane/copper connections pull that heat away.
7. Wave Soldering:
a. Only boards stuffed completely with lead-free parts can run through a lead-free wave soldering process. Otherwise the lead will contaminate the solder, costing upwards of $50K to empty, clean, and refill the wave soldering pot. So we must be absolutely certain all of our parts are lead-free before we request a lead-free wave process. Lead-free wave soldering requires a higher temperature pre-heater for the board, which is not desirable.
b. Due to higher reflow temperatures, Company x does not want to run parts through the wave soldering process for a second reheating. Many parts won’t survive a second re-heating, which is 500C. To prevent damage to SMT parts on the bottom side of the PCBs, they are using “selective wave fixtures” that attach to the boards and only exposes the parts needing wave soldered. These fixtures costs $300-$400 although they may need several to allow them to continue running boards as other fixtures cool enough to be handled. The fixture rules are:
i. No SMT component on the bottom side of the PCB can extend more than 0.125" from the PCB surface. If they are taller, then a more expensive fixture can be built (double layer) or they will have to hand solder the parts. Either way costs us more for assembly.
ii. All SMT parts should be at least 0.100" away from the parts to be wave soldered. This leaves room for the fixture to fit tightly to the PCB. Obviously all of the parts can’t adhere to this rule. In these cases, we should provide build instructions to specify to either glue the intruding part to the PCB and wave solder it (indicating it can handle the heat for a second pass) or to have them hand solder the part to the PCB after the wave process.
8. Pre-Fabrication DFM Review: Company x wants 24 hours to review our PCB artwork before fabrication. This allows them time to review the board and suggest changes for better manufacturability. This also gives them time to look at some of the parts to see if they can handle the lead-free processes and high-pressure post-washing.

September 11, 2006