We have been talking about it for some time now, tin soldering as we know it should disappear. Commonly used for the soldering of electronic components during manufacturing in process of technology, we are therefore directly concerned by this event.
In fact, what is criticized for this alloy is the presence of lead in its constitution and the pollution problems which result from it when old electronic cards are abandoned in the very many products that we use and which unfortunately do not pass. all by sorting and recycling. Abandoned in nature, welding can decompose more or less quickly under the effect of acids contained in the soil or coming from rainwater and pollute the water table. It is therefore to avoid this phenomenon that measures have been taken at European level as in other parts of the world. These are the RoHS directives which thus condemn our little soft thread that our students sometimes have so much pleasure in "putting into balls" when the teacher has his back turned. In fact the directive does not only concern lead, it also concerns other pollutants such as mercury, cadmium, hexavalent chromium and a few others. Likewise, it does not completely prohibit the use of these metals, it only recommends maximum thresholds not to be crossed in their use. The problem with our solder is that the percentage of lead allowed by the RoHS directive is far too low to allow soldering. Here are some sites that will provide you with additional information on the subject:
For its part, MARKEM provides historical benchmarks for the publication in Europe of the RoHS and WEEE directives .
What are the alternatives ?
There are several, on the one hand, the "CMS" ( components mounted on the surface ) are more and more used, that said, that does not completely eliminate the soldering because there are still cables or strips or tablecloths to be fixed on the cards. A second alternative is the arrival of lead-free solder but for the moment, three problems have been reported: this process is more expensive, it is necessary to heat more ( risk for the most fragile components ) and the soldering would be more difficult to achieve, in any case, this is what can be read on the SOLDERTEC site . The KESTER company presents lead-free solutions and describes some of their characteristics. MBO also presents some soldering solutions.
It is possible in the current context. It should be noted, for example, that the company MITI ( Japan ) had decided that none of its products would have contained lead as early as 2001/02. I do not know if they have succeeded but we can very well imagine that a company, even a country takes advantage of its more environmentally friendly technology to make it a selling point and we can also imagine that the advance of new production methods in the hands of economically powerful companies could ultimately lead to the prohibition of the sale of products that do not comply with the directives.
What about technology in all of this?
So far, I have not found any alternative products offered by our usual suppliers. CIF offers equipment for the manufacture of printed circuit boards and the installation of SMD components but these equipment are still expensive and are not very present in colleges. One thing is obvious however, technology will not escape the rule for at least two reasons. The first is linked to the fact that we cannot have a quality technological education advocating production methods that respect the environment if in practice we use products recognized for their harmfulness and which have become banned, our credibility is at stake. . The second is quite simply based on supply possibilities,if the welding rolls we currently use are no longer offered by our suppliers and disappear from the catalogs, we will be forced to do without.
Article by : Emmanuel LE CLAINCHE ( with my sincere thanks ... )