Some would-be attempts to ‘protect’ the environment are sure to blow up.
Two of the major solder suppliers have within the past few months announced their Pb-free alternatives to soldering in the 2000s and beyond. Although their chemistries are different, it is interesting to note that, as seems to happen in these matters, the industry paths have followed a similar approach.
The new processes both make use of reactive metal systems in their chemistry. Existing lead content is replaced by a reactive metal such as sodium or potassium, although at a much lower percentage that the typical 37% or 40%. The idea behind these reactive metal systems is threefold:
To eliminate lead in soldering.
To reduce capital equipment costs.
To reduce consumable material costs within cleaning operations.
In trials it has been found that the optimum mix of the K-based chemistry is 12.5%, and the Na system 11.5%, the balances in both cases being tin. In fact the process, due to the nature of the chemistry, has been perfected only for solder paste formulations, although other methods are being urgently addressed.
It works like this. Potassium and sodium react with water to form a number of K- or Na-alkali salts. A side effect of this is the chemical reaction releases very large amounts of heat. In practice, boards are printed and components assembled. Conventional reflow ovens are eliminated in favor of an aqueous cleaner. Water reacts with the reactive metals to release large amounts of heat, which reflows the joints.
Because the water supply is continuous, the assembly is cooled rapidly while reflowing. This gives the resulting joints a very fine grain structure. The salts formed as a byproduct of the reaction are caustic K- or Na-hydroxides (caustic soda), which of course form the basis of most saponifier systems. Overhead operating costs are thus reduced, because no saponifiers need be added to the aqueous cleaner, and in fact all residues are completely soluble.
These major breakthroughs have been patented and named using a combination of the metals involved, so when the see the launch of SodiT and TinPot solder pastes, remember you heard it here first. And if you got this far without smiling, just remember this is the April issue.*
On a more serious note, I am fed up with reading that the industry is “clamoring” for federal environmental standards for electronics (with the added hint that they follow the RoHS European rules). This is simply not true.
Give me the list of “clamorers,” but make sure it includes people that design and build the stuff, not those who find it logistically inconvenient. With all due respect, companies lobbying for federal standards, but that are not informed (or do not care) about the true environmental impact, or lack a true understanding of the potential reliability issues, in my opinion, do not have views that count in this equation.
In this regard, a large distribution company has been on a roll, and while I am not disputing the company’s concern for the environment, it is obvious that someone there clearly does not have a clue about what, from an environmental perspective, the RoHS directive banning lead in solders is actually doing.
The campaign, as far as I can tell, has not come from any actual understanding and concern for the environment, but rather from an “it’s politically correct so I will follow” attitude derived from a complete misapprehension of the real issues and exacerbated by financial concerns over stocking multiple component lines.
If distributors were truly environmentally concerned to the point of conducting surveys and issuing press releases, perhaps they would research the underlying facts behind the existing and proposed legislation and lobby accordingly.
Likewise, if they are truly environmentally concerned, they have a far simpler choice than presenting the industry with smoke and mirrors. That choice is simple: Do not sell components to any company not certified to ISO 14000 and lacks an environmental policy that includes the organization itself, its upstream supply chain and its downstream EMS providers.
We as an industry have a choice: Take it or leave it, or do something else! But please understand the real environmental impacts of trying to bully through legislation on a global basis, laws that include far-reaching ideas like the lead in solders ban, where the replacement will have a far more negative global environmental impact than the materials replaced. It is crucial that we understand environmental issues, even more so when they are decreed by law. If the law is wrong, it is still the law and must be obeyed. But keep in mind, by definition, a bad environmental law will be bad for the environment.
We have one planet. These are serious issues and should be treated accordingly.
Make your choices. Whether conducting a survey or answering one, be aware that if you are asking for support on, or voting for a subject that you do not truly understand from an environmental perspective, you may be attracting support for bad legislation. And if you are successful in propagating bad laws, you are dragging six billion other people into the mire with you.
*Ed.: The author published the first half of this column in Electronics Manufacture & Test in April 1994. Some jokes never get old.
John Burke is founder of RoHSUSA (rohsusa.com) and an advocate against the RoHS Directive; john@rohsusa.com. His column appears monthly.
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Two of the major solder suppliers have within the past few months announced their Pb-free alternatives to soldering in the 2000s and beyond. Although their chemistries are different, it is interesting to note that, as seems to happen in these matters, the industry paths have followed a similar approach.