XRF equipment and materials characterization for RoHS compliance: an evaluation of five systems showed broad performance differences.
Ed: For the complete article, visit circuitsassembly.com/cms/content/view/5291.We selected two handheld and three desktop XRF spectrometers because of their main specifications, performance and cost. They are Vendor 1-D, Vendor 2-D, Vendor 3-D, Vendor 4-H and Vendor 5-H. We used this XRF equipment for Cpk, stability, Gage R & R, detection level versus acquisition time studies with 12 standard samples, and correlation studies with 11 production samples.
We found:
* Energy dispersive XRF is one of the more suitable analysis methods for parts screening because of its nondestructive, fast and efficient analysis.
* Each XRF has different accuracy levels for measuring banned substances. We suggest obtaining deviation (different) results for main elements of the XRF in order to learn which samples need to be sent to an outside laboratory for confirmation of RoHS compliance.
* In general, desktop XRF performed better than handheld XRF. However, the handheld XRF from Vendor 4 performed better than some desktop XRF. Table 19 summarizes the performances.
* Choose a reliable test laboratory for identifying samples that are inconclusive (in between the RoHS-compliant and noncompliant ranges).
* The experiment results listed are primary studies with XRF for RoHS enforcement. The results obtained from this evaluation showed the equipments' capability to quantify banned substances by RoHS initiative and demonstrated that XRF technique is a feasible testing method for manufacturing to perform quick verifications. However, a safety margin must be chosen to prevent equipment uncertainty from affecting final decisions.
* Despite the benefits of this technique, important limitations should be considered, such as the inability to quantify PBB, PBDE and chromium VI; the inability to detect banned substances in the inner part of a thick component/part; the inability to differentiate the banned substance contents of a nonhomogeneous component/part (the XRF result is a sum of different homogeneous materials), etc. A trial run is highly recommended to study effectiveness before final approval. Also, a well-trained operator is required to judge the results.
Ed.: This article was first published at Apex in February 2007 and is published with permission of the authors.
Hector Rene Marin Hernandez, RefugioVicente Escobedo Alva, Zhen (Jane) Feng, Ph.D., Joao Ofenboeck, and Murad Kurwa are with Flextronics International (flextronics.com); jane.feng@flextronics.com.
Hector Rene Marin Hernandez, RefugioVicente Escobedo Alva, Zhen (Jane) Feng, Ph.D., Joao Ofenboeck and Murad Kurwa
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| Title Annotation: | Comparing XRF |
|---|---|
| Comment: | XRF equipment and materials characterization for RoHS compliance: an evaluation of five systems showed broad performance differences.(Comparing XRF) |
| Author: | Hernandez, Hector Rene Marin; Alva, RefugioVicente Escobedo; Feng, Zhen (Jane); Ofenboeck, Joao; Kur |
| Publication: | Circuits Assembly |
| Article Type: | Reprint |
| Date: | Sep 1, 2007 |
| Words: | 386 |
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