Abstract
Keywords - Lead-free solder alloys, automotive, electronics, wave soldering, reflow soldering
Abstract - The paper explains the experience of the Electrical & Electronic Division of Lear Corporation in applying lead-free solder alloys in some parts of their electronic devices (Smart Distribution Nodes).
The Directive 2002/95/EC on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS) does not consider the electronic devices in the automotive sector because they are affected by the Directive 2000/53/EC on end-of-life vehicles. This Directive tries to ensure that materials and components of vehicles put on the market after 1 July 2003 do not contain lead, mercury, cadmium or hexavalent chromium. However, the use of lead in "Solder in electronic circuit boards and other applications" is allowed without specifying any deadline (Annex II of the Directive).
It is expected that both Directives will converge because they are looking for the same target: reduce the content of lead in the electronic & automotive devices and wastes. However, the operating conditions for these devices are very different (temperature, power, humidity, etc.) and different alloys should be used in each application.
In this paper the steps followed for implementing lead-free solders in automotive commercial products will be described. These steps have been the following:
- Bibliographic research of available studies on lead-free soldering (eg. alloys comparison, etc.)
- Selection of the most promising alternatives for automotive application (SnAg, SnAgCu, SnCu)
- Soldering test in Lear real products (eg. manufacturing problems, equipment changes, etc.)
- Laboratory tests to guarantee OEMs' requirements (validation tests)
- Application to commercial products after OEMs approval
The problems found and the benefits of using these alloys will be explained to illustrate the difficulty of changing to lead-free soldering alloys.
Since year 2000 the Applied Research Dpt. - European Technological Center - has been working in a project with the following three major key drivers: (1) Legislative and customer requirements, (2) Market-driven actions (e.g. customers and competitor activities), and (3) increase reliability of solder joints in front of the new customer requirements for using SDNs in the engine compartment of the car.