Equipment Impacts of Lead Free Wave Soldering

The popular tin (Sn) rich lead free solders are causing severe corrosion to many of the materials used in today’s Wave Solder systems. Users are experiencing higher maintenance frequency and reduced life of wave solder machine components.

This paper describes the effects of Sn rich solders in contact with various materials and discusses alternate methods to alleviate this problem.

In cooperation with the Metallurgy Department of the University of Missouri - Rolla, the Sn corrosion effects were studied for stainless steels, coated stainless steels, titanium, cast iron, and other materials. Corrosion effects and test results are presented for each of these materials. Optical and scanning electron microscopy and x-ray emission chemical analysis were the primary tools used in the evaluation of failed samples. Based upon this research and field trials, recommendations are given which address the expected field life, economic impacts, and materials selections for new or used Wave Solder equipment.