Brief Proposal by Abbydoc

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									3.371 Fall 2002
Stephanie Dalquist
                                      Brief Proposal

The electronics industry, heavy in waste and toxic substances, has been hit particularly
hard by efforts to "green" the industry by removing lead from the manufacturing cycle.
Known health hazards and bioaccumulation problems of lead have led the electronics
industry to focus on the development of lead-free solders for use in printed wiring boards,
where for years tin-lead solders have been the standard.

Although years of research have led to the wide-spread availability of lead-free solders,
the question remains as to whether the life cycle of lead-free solders is actually more
environmentally friendly than that of traditional solder. This paper attempts to address
these issues, especially with relation to temperature issues in the processing and use
stages, and recycling at end-of-life.

                                          Outline

I. Introduction
II. Traditional solder
        A. Content
                1. Lead-tin
        B. Characteristics
                2. Different % qualities, uses
III. Lead-free motivations
        A. Problems
                1. Health
                2. End-of-use: landfilling, burning bad
        B. Regulations
                1. European WEEE Directive
        C. Cost
        D. Competition
                1. Consumer perception
IV. Lead-free alternatives
        A. Content
                1. Systems
        B. Characteristics
        C. Problems
                1. Process related
                       a. Higher process temperature
                               i. Different substrates required
                               ii. More energy intensive
                2. Life cycle problems
                       a. Use
                               i. Thermal fatigue
                               ii. Metal migration
                       b. Recycling & Take-back
                             i. Contaminant
                             ii. Metal migration
               3. Other
V. Solder alternatives
VI. Conclusions

                                       References

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Mount Boards Manufactured with Lead-free Solders.” Proceedings of Surface Mount
International Conference. pp. 437-448. San Jose, CA, 1994.

								
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