Circuits Assembly - November 2008 - (Page 33)

Cover Story for supplier failures should quickly determine root cause and also track and trend supplier performance. Another consideration is the effectiveness of an XRF in isolating hexavalent chrome (Cr6). XRF will detect the base element (chromium), but not the compound (Cr6). Secondary laboratory tests would be needed (wet chemical test) to detect the banned Cr6 substance. Another option upon getting a high chromium reading is to contact the vendor; if they are reputable and confirm in writing the chromium is not the banned form, this could be considered an appropriate level of due diligence. Case Study Benchmark typically provides both EOL and RoHS BoM analysis for customers. Six different medical products were analyzed for this paper. The cycle time for this analysis can run from three weeks to four months, depending on BoM size and supplier responsiveness. Three passes are performed on the BoM. This approach begins by first evaluating the BoM for completeness and accuracy. Typically, a number of components have inaccurate manufacturer and manufacturer part numbers. Second, Web-based databases are used for the initial data collection. The hit rate for data from these databases is typically 50 to 70% for EOL status. RoHS compliance identified in the database is typically 10 to 20% in a “Yes/No” format and <5% at a homogeneous material level. The final pass involves component engineers who work directly with the supplier. When contacting the supplier directly, homogeneous level information is typically provided in 10% of the cases. With a strong supplier relationship, this can be increased to 50 to 70%. Also with direct supplier contact, we typically achieve 90 to 95% EOL status. There are three statuses provided: 1. The BoM is scrubbed in its current state and components are classified as planned (not yet released), preliminary (data sheet is preliminary), active (available), NRND (not recommended for new design) and EOL. 2. The second report looks at the EOL detail and identifies what is currently obsolete, which year a component is predicted to go obsolete, which ones are planned for obsolescence (no time frame identified) and which are not planned for obsolescence. 3. The RoHS report identifies parts as compliant (RoHS available with an existing part number), available (RoHS with a new part number), probable compliant (vendor implies compliance), planned (scheduled), not available and EOL. It should be noted material that is EOL on the existing BoM may be available in the RoHS BoM. This is an indicator of vendors that are obsoleting SnPb components in favor of RoHS-compliant packages. This may be a risk for maintaining a SnPb product. EOL material identified in the RoHS status is a risk for long-term product sustainability. Results. Across these six different medical products, some interesting statistics were identified. On average for RoHSconverted BoMs: • 92% (range 88 to 99%) of the components were available in a RoHS-compliant package. • 56% (range 31 to 99%) of the components’ part numbers circuitsassembly.com were not changed when converted to RoHS. • 2% (range 0 to 4%) of the components on the RoHS BoMs were EOL. • 1% (range 0 to 2.6%) of the components was not available in a RoHS package. On an average for the SnPb BoMs: • 8% (range 0 to 16%) of the SnPb components were NRND. • 4% (range 0 to 14%) of the SnPb components were becoming obsolete (component EOL, RoHS-compliant only). • 12% (range 0 to 29%) of the SnPb components fell into either NRND or obsolete categories. Key observations for these six BoMs: • No BoM was completely converted to RoHS compliance. At least one part would require an alternate or redesign. • For the SnPb BoMs, 12% of the components were obsolete or NRND. For the RoHS BoMs, 2% of the components were obsolete. This would suggest a number of components are transitioning to RoHS compliance and are no longer available in a SnPb package. Conclusions Current environmental requirements and regulations for compliance indicate the medical market has anywhere from four to 12 years before its products must be compliant. Based on the length of a new medical product development cycle, clinicals, the cost of validation and FDA submittal, medical OEMs should be positioning themselves to be compliant. Long product life within the medical market would suggest OEMs’ new products be released already compliant, versus trying to convert a product later and risk revalidation and FDA submittal. Tin whisker risk mitigation strategies should be adopted to reduce potential problems. At a minimum, medical OEMs should be monitoring current product components and BoMs for obsolescence, to avoid production flow impacts. Component packaging should be monitored to detect changes in lead finish and associated Snwhisker risk, along with monitoring BGA ball alloys to identify solderability and process risks. The medical OEM should monitor the BoMs/components of the current production products to ensure supply and new product designs are compliant. Internal procedures and methods should be updated so internal processes can be monitored to ensure new products will ship compliant.n Ed.: For a list of references please visit circuitsassembly.com/cms/content/view/7316. Ed.: This article was first published at the SMTA Medical Electronics Symposium in January 2008 and is used with permission. Kim Sharpe is corporate director of engineering at Benchmark Electronics (bench. com); kim.sharpe@bench.com. Circuits Assembly NOVEMBER 2008 33 http://www.circuitsassembly.com/cms/content/view/7316 http://www.circuitsassembly.com

Table of Contents Feed for the Digital Edition of Circuits Assembly - November 2008

Circuits Assembly - November 2008 Contents Caveat Lector Industry News Market Watch Talking Heads Focus on Business On the Forefront Screen Printing Better Manufacturing RoHS Conversion for Medical Devices Supporting Full-Service Customer Requirements at the Regional EMS Level Speed Thrills Tech Tips Wave Soldering Process Doctor Pb-Free Lessons Learned The Defects Database Getting Lean Materials World Product Spotlight Ad Index Assembly Insider Technical Abstracts

Circuits Assembly - November 2008

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