A customer called the EMPF Helpline with a question regarding the screening of an assembled circuit board for lead-free compliance...

The EMPF Helpline fields a number of questions regarding lead-free components and RoHS (Restriction of Hazardous Substances) compliance concerns. Recently, an EMPF customer wanted to conduct screening of a particular assembly according to the lead-free RoHS directive. This directive specifies that, in order to be compliant, each component within an assembly must meet the specified RoHS maximum concentration limit of 1000 ppm, by weight.

The EMPF staff has the capability to quickly perform lead-free screening, using the X-Ray Fluorescence (XRF) technique. XRF is a primary non-destructive test method to ensure lead-free RoHS compliance. XRF is also advantageous in that it does not require sample preparation, and only minimal operator training. Furthermore, RoHS compliance by component suppliers is neither universal, nor standardized; thus a part number or descriptor may not specify whether or not the part meets the RoHS directive.  Use of XRF can help alleviate such an uncertainty. Figure
2-1 shows a sample spectrum of a component using the Fischer Scope XRF. Note that for the sample shown, the component contains an amount of lead which exceeds the RoHS maximum concentration limit.

The customer’s assembly contained many components mounted to a circuit board. The EMPF utilized the XRF technique to determine that one of the components mounted to the board did in fact contain a SnPb finish. According to the RoHS directive, this assembly was deemed non-compliant with RoHS. The EMPF staff was then able to recommend a lead-free replacement for the specified component, allowing the assembly to meet the lead-free RoHS directive specifications.

The EMPF also offers a comprehensive lead-free training seminar. This course provides an extensive overview of RoHS legislation, and discusses materials, manufacturing processes, and reliability differences associated with lead-free soldering. Understanding the most recent RoHS legislation is essential in remaining competitive in the High-Tech industry.  Likewise, misunderstanding or non-compliance of the RoHS directive can potentially subject a company to penalties and potential legal consequences. Many considerations must be taken into account when choosing the material and manufacturing process in order for an assembly to be considered lead-free RoHS compliant. The EMPF training course offers the necessary training for the student to become fully capable of lead-free implementation in the design and manufacturing environments.