How safe is the lead-free environment?
07 June 2006
The aim of the LEADOUT project is the removal of lead from solders and pastes in electronic circuits, so it is important to study the environmental aspects of this change. That is why it is essential to quantify the environmental effect of the present SnPb solders and pastes and to compare them with the lead-free solders and pastes. Dr. Patricio Aguirre gives an update of the project's progress
The main objective of emission measurements is to know more about the kinds of wastes generated when assembling electronic circuits (mainly fumes and slags), to do their chemical analysis (metals, and organics from fluxes), and to quantify these contents.
For the purposes of this project, emission measurements were first of all performed for reflow and wave processes using SnPb pastes and solders at a PCB manufacturer. Once lead-free is fully implemented at the LEADOUT consortiunm's SMEs, new emission measurements will be performed. With both sets of data are available, a further study will be performed in order to compare both processes and to quantify how much better (if at all), from a Environmental point of view, are the selected lead-free solders and pastes compared to the present SnPb. In order to select the good lead-free solders and pastes, not only will the technical aspects be considered, but economical and environmental aspects will also be taken into account.
Besides the mentioned measurements, in order to evaluate the workers occupational exposure in respect to the chemical agents emitted during the soldering processes (reflow and wave) some occupational exposure measurements have been performed using personal sampling pumps in the breathing zone of the worker working with SnPb (once lead-free is implemented new measurements will be made). After sampling, the contents for lead, formaldehyde and isopropyl alcohol have been analyzed and evaluated.
LCA (Life Cycle Analysis) is the tool that is being used to manage all environmental aspects and will allow us to compare both processes in a quantitative way in terms of energy consumption, recyclability, leachability, toxicity and environmental effects of lead-free solders, etc.
Emission measurements performed
Emission measurements have been performed for wave (63/37 SnPb) and reflow (62/36/2 SnPbAg) soldering processes at three LEADOUT assemblers of the consortium, and at the PCB manufacturer (63/37 SnPb) in the LEADOUT consortium.
The mass balance for wave process shows that 68% of the initial SnPb is on the PCB, 32% in the slag and only 0.04% in the fumes.
Occupational Exposure measurements performed
Occupational Exposure measurements have been performed at two LEADOUT assemblers for wave (63/37 SnPb) and reflow (62/36/2 SnPbAg) soldering processes, and at the PCB manufacturer (63/37 SnPb).
Conclusions
Data obtained from emission measurements show that in all cases, the German TA LUFT 2002 limits of the parameters have not been reached neither for VOCs nor for metals.
In the same way, for performed Occupational Exposure Measurements to establish the dangerous aspects for the Health and Safety of workers, it can be concluded that in all studied cases, the measured values are under TA Luft limit values.
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