RoHS: An update on this important Green Initiative
RoHS Exemptions
Exemptions to RoHS are granted to narrowly-defined applications for which the elimination of prohibited substances is technically or scientifically impracticable or when the only available substitution produces more negative than positive benefits to the environment, health, or consumer safety.
Exemptions are temporary in nature and subject to review at least every four years, until such time as a reliable and safe substitution is available. For this reason, many exemptions carry an expiration date.
On September 24, 2010, the European Commission adopted a substantially revised list of RoHS exemptions and replaced the entire Annex for clarity. Currently there are 39 exemptions in RoHS directive.
Hazardous and High-Tech trash problem
RoHS and other efforts to reduce hazardous materials in electronics are motivated in part to address the global issue of consumer electronics waste. As newer technology arrives at an ever increasing rate, consumers are discarding their obsolete products sooner than ever. This waste ends up in landfills and in countries like China to be "recycled.
In addition to the high-tech trash problem, RoHS acknowledges the long-term effects of low-level chemical exposure on populations. New testing is capable of detecting much smaller concentrations of environmental toxicants. Researchers are associating these exposures with neurological, developmental, and reproductive changes.
RoHS is in contrast to historical and contemporary law that seeks to address only acute toxicology that is direct exposure to large amounts of toxic substances causing severe injury or death.
Life-Cycle Impact Assessment
1. Lead-free solder. Study results are providing the industry with an objective analysis of the life-cycle environmental impacts of lead-free solders, allowing for practical consideration of environmental concerns along with the traditionally evaluated parameters of cost and performance. This assessment is also allowing manufacturers to redirect efforts toward products and processes that reduce solders' environmental footprint, including energy consumption, release of toxic chemicals, and potential risks to human health and the environment.
2. BFR-free plastics . The ban on concentrations of brominated flame retardants (BFR) above 0.1% in plastics has had an impact on plastics recycling. As more and more products include recycled plastics, it has become critical to know the BFR concentration in these plastics, either by tracing the origins of the recycled plastics to establish the BFR concentrations, or by measuring the BFR concentrations from samples. Plastics with high BFR concentrations are costly to handle or to discard, whereas plastics with levels below 0.1% have value as recyclable materials.
Benefits of RoHS compliance
RoHS helps reduce injury to people and damage to the environment in third-world countries where much of today's "high-tech trash" ends up. The use of lead-free solders and components has provided immediate health benefits to electronics industry workers in prototype and manufacturing operations. Contact with solder paste no longer represents the same health-hazard it did before.
Reliability concerns unfounded. Contrary to the predictions of widespread component failure and reduced reliability, today, millions of compliant products are in use worldwide. Most of today's consumer electronics are now RoHS compliant. Examples include Apple's iPod portable music players as well as Dell and HP home computers and servers
Flow properties and assembly. One of the major differences between lead-containing and lead-free solder pastes is the "flow" of the solder in its liquid state. Lead-containing solder has a lowe surface tension and tends to move slightly to attach itself to exposed metal surfaces that touch any part of the liquid solder. Lead-free solder, conversely, tends to stay in place where it is in its liquid state and attaches itself to exposed metal surfaces only where the liquid solder touches it.
Lack of "flow". While typically seen as a disadvantage because it can lead to lower quality electrical contact, this can be used to place components in tighter proximity than they could be placed when using lead-containing solders.
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