Many of you out there may not realize it, but we are headed for a fall.
No, I'm not talking about civilization falling or the end of the world. It's nothing so dramatic. But to some folks it may seem like the end of the world when it happens.
What am I talking about?
Something called RoHS.
RoHS is an acronym for Restriction of Hazardous Substances.
You may be asking what this may have to do with the disaster I've been skirting around. After all, RoHS sounds like something that everybody would want.
RoHS was created by the European Union in an effort to remove toxic substances from consumer and commercial electronic and electrical devices. At the moment there are six substances banned by RoHS: lead, mercury, cadmium, hexavalent chrome, PBDE, and PBB.
The first four are heavy metals, each toxic in its own way. The last two are fire retardants used in certain plastics. I think that just about everyone can agree that it would be nice to be able to remove these substances from products that we use every day. Obviously there are exemptions that allow the use of these substances, but they are few and far between, usually for critical equipment where an acceptable substitute hasn't been found.
Again, all of this sounds like something that everybody could get behind. But as happens with many good things, sometimes there are unintended consequences.
One of the banned substances, lead, is in the solder that is used to put electronic parts onto circuit boards. Most electronic solders have between 37 and 40 percent lead. The rest is usually tin. But with RoHS, lead has to be removed from solder. The solders used for lead-free soldering are mostly tin, usually 96 percent or more, with the rest if the solder being silver or gold and copper.
This new solder mix has two problems. First, it requires higher temperatures to melt the solder. The higher temperatures require newer materials in the circuit boards and electronic components that will withstand the higher soldering temperatures. Second, and probably most important, solders with a high tin content have the unfortunate tendency to grow whiskers.
Yes, whiskers. Over a period of time, depending upon conditions like temperature, humidity, vibration, and so on, can promote the growth of tiny tin whiskers thinner than a human hair. Given enough time they can grow long enough to short out against an adjacent component, causing a failure. An expensive TV, computer, cell phone, dishwasher, or clothes dryer will become just another paperweight, and all because of a tiny tin whisker.
“But surely there must be some way of preventing such a thing from happening?” you may ask. The answer is, regrettably, no. While there are ways of delaying such an event, there is no guaranteed method of preventing it. That's the problem with RoHS.
While the EU was smart enough to provide exemptions for mission- and life-critical electronics such as medical, aviation, military, and some telecommunications equipment, I believe they made an error when it came to consumer and commercial electronics.
Much of this came about because consumer electronics over the past decade or so have grown so common with the advent of cell phones, PDAs, MP3 players, and computers that a lot of this type of equipment was going into the waste stream as people upgraded to the newest/latest/greatest gizmo. This meant that hundreds of millions of electronic products were being dumped into landfills every year. Along with those products were a number of toxic substances. It is because of this that the EU implemented RoHS. But it's one thing to implement such a directive and yet another thing to live with the effects of the directive.
What will happen as millions of electronic and electrical devices start failing due to tin whiskering because of the RoHS compliant solders and electronic components? For those folks that routinely change cell phones every year or so it may make no difference. But the rest of us will have to deal with electronics that likely will not be reliable after a year or two. For businesses that depend upon reliable electronics to fulfill their functions it will become a nightmare. For manufacturers it will be a living hell as they will suffer the fallout from the compromised quality of their products, something they will have little control over in this instance.
With this in mind, many are starting to question the wisdom of including lead in the list of banned substances. As alloyed with tin in solder, the lead won't leach out while buried in a landfill. That means it won't contaminate the soil or the ground water, so that argument won't fly. The removal of lead from electronics has more side effects than letting it remain, including requiring more energy to produce RoHS compliant products because of the higher temperatures required to manufacture them.
While RoHS is limited to the EU for now, it will expand its reach over the next few years. China's version goes into effect next year. A small number of states in the US have passed RoHS-like regulations and more are expected to do so.
This is going to be ugly.