Restriction of Hazardous Substances Directive - Criticism

Criticism

Adverse effects on product quality and reliability, plus high cost of compliance (especially to small business) are cited as criticisms of the directive, as well as early research indicating that the life cycle benefits of lead-free solder versus traditional solder materials are mixed.

Criticism early on came from an industry resistant to change and a misunderstanding of solders and soldering processes. Deliberate misinformation was espoused to resist what was perceived as a "non-tariff barrier created by European bureaucrats." Many believe the industry is stronger now through this experience and has a better understanding of the science and technologies involved.

One criticism of RoHS is that the restriction of lead and cadmium does not address some of their most prolific applications, while being costly for the electronics industry to comply with. Specifically, the total lead used in electronics makes up only 2% of world lead consumption, while 90% of lead is used for batteries (covered by the battery directive, as mentioned above, which requires recycling and limits the use of mercury and cadmium, but does not restrict lead). Another criticism is that less than 4% of lead in landfills is due to electronic components or circuit boards, while approximately 36% is due to leaded glass in monitors and televisions, which can contain up to 2 kg per screen.

The more common Lead-free solder systems have a higher melting point e.g., a 30 °C typical difference for tin-silver-copper alloys but wave soldering temperature is approximately the same at ~255 °C; however at this temperature most typical lead free solders have longer wetting times than eutectic Pb/Sn 37:63 solder. Additionally wetting force is typically lower, which can be disadvantageous (for hole filling), but advantageous in other situations (closely spaced components).

Care must be taken in selection of RoHS solders as some formulations are harder with less ductility, increasing the likelihood of cracks instead of plastic deformation, which is typical for lead-containing solders. Cracks can occur due to thermal or mechanical forces acting on components or the circuit board, the former being more common during manufacturing and the latter in the field. RoHS solders exhibit advantages and disadvantages in these respects, dependent on packaging and formulation.

The editor of Conformity Magazine wonders if the transition to lead-free solder will affect long-term reliability of electronic devices and systems, especially in applications more mission-critical than in consumer products, citing possible breaches due to other environmental factors like oxidation. This article refers to the Newark InOne "RoHS Legislation and Technical Manual", which cites these and other "lead-free" solder issues, such as:

1. Warping or delamination of printed circuit boards;
2. Damage to through-holes, ICs and components on circuit boards; and,
3. Added moisture sensitivity, all of which may compromise quality and reliability.