Restriction of Hazardous Substances (RoHS) legislation has resulted in essentially a global ban on the use of solders containing lead in electronics production. Cord Master Engineering is familiar with RoHS compliance measures.
RoHS Compliance Exceptions
There were permitted exemptions to RoHS compliance for military and aerospace components who still needed to use leaded solders. Very quickly after the legislation was passed, nearly all component manufacturers converted virtually all of their components to lead-free solders. These solders include Tin-Silver-Copper SAC. This mass conversion left those with exemptions with no source for components for tin-lead solder.
As the need for these components continued it led to the formation of a niche industry whose business was using hot solder dipping to remove pure tin finishes from component terminations and replace them with tin-lead solder. The most important requirement for this process is that all of pure tin must be removed in a process called tin whisker mitigation. Dipping the component’s terminations in hot tin-lead solder right up to the body of the component is the solution.
Unfortunately, hot dipping means that the body of the part can be subject to thermal stresses. Precise control is required during the entire operation including steps such as fluxing, dipping, and cleaning. The absence of such precise controls can cause internal damage to the component.