Circuits Assembly - November 2008 - (Page 31)

Cover Story tight controls on new RoHS-compliant laminates. When converting the BoM, the OEM may find some components unavailable or only available with lead finishes iNEMI Figure 1. Sanding and abrasion lines. does not recommend due to the potential Figure 1. Sanding and abrasion lines. of tin whiskers. This may require a level of product redesign that may result in submitting the device to the appropriate Figure 1. Sanding and abrasion lines. government bodies for approval. This Figure 1. Sanding and abrasion lines. would involve product verification and validation activities. If FDA resubmittal is required, it may be prudent to implement a full RoHS conversion of the product. In addition, when the next product generation is developed or a new product designed, a RoHS-compliant development should be considered. With the Figure 2. Recoating over the sanded surface. new materials used for compliance, such Figure 2. Recoating over the sanded surface. as assembly materials, solders, etc., the Figure 2. Recoating over the sanded surface. may want to conduct additional OEM reliability testing, cross-sectioning and analysis. The general consensus among Figure 2. Recoating over the sanded surface. participants of the IPC Pb-free Solder Reliability Conference was that long-term reliability of these new materials is not definitive. More life testing and analysis is needed. Figure 3. Relabeled component. EFD Lead-free Solder Paste Now packaged in New Optimum™ Green Cartridges High-impact strength & dimensional stability ZeroDraft™ design ensures consistency Company/Process Conversion Even if a medical OEM is converting its Figure 3. Relabeled component. Double-wiper piston products to RoHS compliance, it might • Supplier material declaration docueliminates waste not have to have all the internal proment. cesses in place to prove compliance to any • Lead finish or plating. Figure 3. Relabeled component. • Tin-whisker mitigation status and test legal entity. While medical OEMs remain Figure 3. Relabeled component. exempt from RoHS compliance in the results. EU, they should consider changing inter• Maximum case temperature. nal methods and processes to a degree • MSL. that would support compliance should There are other factors to considthey convert later on. er as well. When selecting components, Converting to RoHS compliance has designers should consider maximum case a significant impact on documentation temperature; some components may be and documentation systems. Areas to be RoHS-compliant, but their case temperFigure 4. not survive manufacturing considered AM7969-125JC Receiver; ature may Component package marking for an AMD for product documentation: however, the dies were an AM7968-125JC transmitter and an NEC • Part numbering scheme to handle and process temperatures. Some component PD71051 serial control unit. identify component compliance. lead finishes have a higher likelihood of • Component specification prints/drawdeveloping tin whiskers. Material declaraFigure 4. be on supplier letterhead or ings AMD AM7969-125JC data. tion should Component package marking for an should include complianceReceiver; however, the dies were an Figure 4. Component package marking for an AMD serial control unit. dies were an AM7968-125JC transmitter and an NEC PD71051 AM7969-125JC Receiver; however, theThe Clear Advantage™ • A field in the BoM to identify complidocumentation with appropriate signaAM7968-125JC transmitter and an NEC PD71051 serial control unit. ance. ture. Finally, with higher manufacturing • Custom part drawings and compliprocess temperatures, many components’ ance language to identify compliance MSL will change to reflect better controls requirements to the custom suppliers. for storing and handling of these materi800-338-4353 +1-401-434-1680 • Fabrication prints and notes reflecting als. MSL level is critical for PCBs, and www.efd-inc.com/ads/ca-1108 RoHS compliance requirements. the fabricator and assembler must keep circuitsassembly.com Circuits Assembly NOVEMBER 2008 31 http://www.efd-inc.com/ads/ca-1108 http://www.efd-inc.com/ads/ca-1108 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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