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RoHS compliance testing
Recent enforcement of the RoHS directive is now upon the electronics industry. By which legistlation states products placed on the electronics market must be manufactured in accordance with this protocol. In response to this new industry demand Soldertec Global have launched a new RoHS screening service aimed at testing finished products to confirm they are fully compliant. Joanna Symons of Soldertec Global discusses the advantages of this new service and how it provides a solution, laying out a step-by-step guide to RoHS compliance investigations.

The EU Restriction of Hazardous Substances (RoHS) Directive prohibiting the use of certain substances in electrical and electronic equipment came into effect from the 1st July 2006. Electronic equipment importers and manufacturers are likely to be the first line for enforcement. Products placed on the market after 1st July 2006 are presumed to comply with RoHS requirements.

RoHS clearly has significant implications for all parts of the supply chain from suppliers to manufacturers, as the restricted substances may be found in a wide range of applications (Table 1).

Compliance testing
The RoHS Directive specifies maximum permissible concentration values of hazardous substances in homogeneous materials, i.e. materials that cannot be mechanically disjointed into different materials and which are of uniform composition throughout. The maximum permitted concentration of these substances is 0.1% by weight of homogeneous material, except in the case of cadmium, where the limit is 0.01%.

For this reason, there is no simple test for RoHS compliance – testing has to be conducted on each of these materials individually. A draft IEC standard (111/24/CD) has recently been issued and this details a two-tier approach comprising an initial screening procedure followed by a more quantitative verification procedure. (see Table2)

Soldertec Global Screening
The X-ray fluorescence (XRF) is probably the most cost-effective and convenient technique for the preliminary screening stage. Low cost, portable, hand-held devices are being used for ‘in the field’ analysis, although these are usually limited with regard to detection limits and focus on small areas. Higher cost, bench-top instruments give better accuracy and can analyse components whole or those that have been dismantled or sectioned.

Visually these two BGA devices appear identical, but one is lead-free and the other is not. XRF picks up the difference very clearly.

The use of XRF enables rapid determination of lead, cadmium, mercury, chromium and bromine, although speciation (required in the case of hexavalent chromium, PBB’s and PBDE’s) is not possible. If levels of these elements are close to the RoHS critical limits, then there is a requirement for more accurate analysis using an appropriate verification technique (see Table 3).

RoHS Assurance Testing Program
Soldertec Global launched a new RoHS screening service on the 1st July 2006, to coincide with the enforcement date of the RoHS Directive within the EU States. This service is specifically aimed at finished products and sub assemblies to help them comply with the requirements of the Directive. The final report generated from this service will provide an extra assurance that materials declarations from the supply chain are trustworthy.

Most historical uses for restricted substances are known, so that "high concern" materials or applications can be targeted for sampling. Based on many thousands of individual tests carried out by Soldertec Global, parts of a finished product or assembly, which are deemed at highest risk of containing restricted materials, are quickly identified and the RoHS Assurance test program can select and test these parts.

"Initially we will test and report on 10 points, which we consider to be of highest risk. This gives us an opportunity to test some of the highest risk parts and assess the need for further testing on the rest of the assembly. " comments Tom Perrett, Marketing Manager, Soldertec. "The points for testing are selected according to what the technologist sees before him. Certainly we would select solder joints, both topside and bottomside of a PCB, plus any obvious hand soldered joints. Coloured cables need testing as we have picked up lead, cadmium and chromium used as colourants. But there are many other places that we have seen that require spot checks."

If the initial assessment shows more than ten points of high risk then this will be indicated to the client.

“It is impossible to guarantee that all RoHS non-compliant parts will be found, given the number of potential materials present in a typical product and the limitations of the testing, which is the nature of a risk-based approach," comments Tom Perrett.

Testing is consistent with IEC ACEA ad hoc Working Group draft standard "Procedures for the Determination of Levels of Regulated Substances in Electrotechnical Products".

Whilst Soldertec Global does not provide certification of conformance, on completion of testing, it does issue a clearly-written, comprehensive and confidential report setting out the findings of their analysis of the product being tested.

Tom Perrett continues "we believe this to be a crucial service that will provide considerable benefit to the electronics industry struggling to comply with the RoHS Directive."

In May 2006, the UK DTI released the RoHS Enforcement Guidance Document which looks at the underlying principles that might be used throughout the 25 EU states to guide RoHS enforcement. It considers the enforcement process, RoHS compliance documentation, plus sampling and testing.

The guide lays out a step-by-step approach to RoHS compliance investigations - initial selfdeclaration; followed by a more detailed assessment in those cases where evidence from producers does not assure compliance. In cases of concern, detailed sampling and testing may or could be required. Examples of issues that need to be addressed include: is the supplier part of a global chain or a small previously unknown company? Is there a long-term working relationship with the supplier? Has their production facility ever been audited?

As more companies become aware of legislation around the world restricting the use of certain materials many companies look to JIG 101 for details of such materials. The Joint Industry Guide, JIG 101, lists materials that are currently subject to enacted legislation; or are of significant environmental, health or safety interest; or would trigger hazardous waste management requirements; or would have a negative impact on end-of-life management. The screening method used at Soldertec Global can be used to detect most of the elements present on the JIG 101 lists.