Friday, May 16, 2008

Lead in Soldering: The Electronic Industry’s Weakest Link?

Ever since that worldwide movement to ban the metal lead from our everyday lives started very near the tail end of the 20th Century, consumer electronic manufacturing firms are busy searching for a replacement. Is this even feasible?

By: Vanessa Uy

Even though everyone’s fears about the heavy metal lead and it’s toxic effects on our bodies is not entirely irrational, many environmental pressure groups had been lobbying to anyone willing to listen to them for the total ban of the toxic metal lead from our everyday lives. Though an admirable goal, I really have some serious doubts about the practicality and feasibility of their lofty goals. Especially if these people are just lazily sitting back and not even formulating their own billion-dollar solutions.

Scandinavian countries have already eliminated the use of the toxic liquid metal mercury from all of their medical diagnostic instruments – i.e. thermometers – when the 21st Century came along. Legislating similar laws to phase out other “potentially toxic” substances from our everyday lives is easier said than done. Especially if our so called environmental pressure groups are already very much inebriated by the “poisoned fruits” of Web 2.0.

Take the soldering lead for instance. This humble tin and lead alloy is probably used by humanity for thousands of years, yet it is still an indispensable part of the consumer electronics industry. Especially when it comes to attaching microprocessors and other components to the circuit or PC board. It’s very likely that a majority of the passive consumers of our consumer electronics industry does not – and will not – give a damn about the miracles of lead-based soldering. Only the manufacturers and a dedicated few electronics hobbyists and DIY enthusiasts cares about how the lead content of our soldering is what help us perform those very tangible miracles we do everyday, even if we are the only witness to this miracle. The miracle of turning a fistful of wires and components into a full-blown symphony orchestra. Some even resort to monitoring the presence of lead in their bloodstream close to a daily basis.

There had been countless attempts over the years to replace lead-based solders in the consumer electronics industry. They range from very low melting point bismuth alloys, lead-free tin solders, even conductive polymers i.e. plastics that conduct electricity. So far, only bismuth and lead-free tin alloys have shown promise in replacing lead-based solders and even then these have their hosts of problems. Those bismuth-based alloys are even available in forms that will melt in warm water since they are originally used as triggering devices in fire suppression sprinkler systems. The only catch in using it is that bismuth based soldering alloys does not form strong joints to the components you are soldering to, unlike the proven reliability of lead-tin soldering alloys.

Lead free tin soldering alloys had been tried in the past for their potential in replacing lead-based soldering alloys. The problem with lead free tin solders is that they have a higher melting point than their lead-based counterparts, which increases their working temperature. The higher working temperature also increases the likelihood of damaging the electronic components that are to be attached / soldered on to the circuit board. Manufacturing “dry runs” had even resulted to the dreaded “pop-corn effect”, which occurs when residual moisture in the epoxy coating that shields an integrated circuit component vaporizes at the high temperatures needed to melt these newfangled lead-free solders. The epoxy then detaches from the chip device and pops open, which allows contaminants like airborne dust particles to enter and can even cause stresses in the coating.

Also a replacement for lead-tin solder is not cheap. An electronic industry insider even said that a viable replacement could cost the US consumer electronic industry alone upwards of a billion dollars annually, depending on the materials incorporated. Economics aside, the question now lingers on whether the volume increase in e-waste caused by unreliable electronic products failing is better than waiting for everyone to throw their lead-filled electronics to the trash heap 80 or a hundred years from now. Which do you think is more environmentally friendly?

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