Citation
(1999), "Industry welcomes lead-free guidance", Soldering & Surface Mount Technology, Vol. 11 No. 3. https://doi.org/10.1108/ssmt.1999.21911cab.007
Publisher
:Emerald Group Publishing Limited
Copyright © 1999, MCB UP Limited
Industry welcomes lead-free guidance
Industry welcomes lead-free guidance
Responding to concerns expressed by the Electronics Manufacturing Industry Forum (EMIF) concerning the Year 2004 ban on lead included in the European Union's draft proposed directive on waste from electrical and electronic equipment (WEEE), the Department of Trade and Industry has published an 80-page report analysing the current status of lead-free soldering. The two-month data gathering investigation was conducted on behalf of the DTI by the National Physical Laboratory and the International Tin Research Institute.
Copies of the report are available on request, free of charge, by calling 0181 943 6459, or e-mail: lead.free@npl,co.uk
Containing a wealth of relevant information on the lead-free issue, the report confirms there is currently no universal drop-in replacement for tin-lead. However, it does conclude that, although key implementation issues need to be addressed, lead-free soldering is technologically possible. The report points to alloys based on Sn-Ag-Cu as being one of the most promising candidates for general purpose soldering. Other alloys regarded as having potential are Sn-0. 7Cu, Sn-3.5Ag and Sn-Ag-Bi.
The majority of lead-free alloys require higher process temperatures than SnPb solders, and the process windows are narrower, the report's authors conclude, In many cases, processes and equipment will have to be modified, as may the criteria for visual and X-ray inspection.
Although the supply of components with lead-free leads/terminations is currently limited, there is no shortage in Europe of lead-free solders and lead-free PCB finishes. Furthermore, compatibility problems between these PCB coatings and lead-free alloys are not anticipated. The report also notes that the indications to date on reliability are that joints made with the proposed replacement lead-free alloys are at least as good as those made with SnPb.