Circuits Assembly - October 2008 - (Page 26)

Medical Electronics MANUFACTURING ENGINEERING Assembly PROCESS START NX0400-001 Rev A 06/11/04 From Sales for quote process Customer Requirements Pre Production Engineering PE reviews and feedbacks to Sales on Nexlogic capabilities vs. customer requirement. Includes DFM analysis and decisions about Fixtures, Tooling, SMT programming and Press Fit, Etc. P.O.Placed W/O Issued W/O page in ERP, Hard copy of Work Order Review Sales Order Includes BOMS, DWGS, Work Instruction, Electronic Data ( Cad, Gerber for Pick and Place ). Review Doc Released Figure 2. Custom test fixtures are commonplace, given the specialized nature of medical electronics. Pick and Place Stencil Printer Programs: (NX0302-001) (NX0301-001) Reflow and Wave Profiling (NX0303-001) (NX0305-001) Fixtures Stencils Tooling Refer to Manufacturing Engineering Procedure NX0400-002 Refer to NX0400-012 REV A for instruction Generate MPI/Traveler Figure 1. Manufacturing engineering process flowchart. Reference the Quality Database for the current revision ty net is. The FDA wants to know what those safety procedures are Page 1 of 1 and how they are evaluated in terms of validation coverage. Also, the FDA wants to know the level of independent review those changes have undergone. For instance, did those changes go through an internal technical committee or did feedback come from non-development team members? On the other hand, if self-validation is performed, it will then be difficult to defend those changes during an audit. The FDA performs hazard analysis as part of a documentation review. It seeks the hazard mitigation techniques detailed in the documentation and how a product’s residual risk is described and justified. It wants to know the residual risks designed into design changes for a specific product. The probability of a problem may not be initially apparent. But after a medical electronics product has been in use for a year or two, the FDA wants to know of any residual risk of that product failing. Printed Copies are UNCONTROLLED outside test vendors. For example, special testing is needed for capturing such radiation devices as “x radiation test”; most EMS providers lack this kind of testing capability. Therefore, special testing pays handsome dividends because it plays an important part in increasing quality and reliability standards, minimizing warranty costs and testing specific applications. Complying with ISO 10993-l is a case in point for special testing. It was adopted by the European Union in 1993 and amended in 2007, and any medical product marketed and sold there must be qualified to it. This standard describes general principles governing biological evaluation of medical devices; device categorization based on the nature and duration of contact with the human body and its fluids, and selection of appropriate tests. Hence, testing requirements are very specific. RF designs for small transmitters or medical telemetry devices worn by hospital patients also require special testing. These miniature products transfer patient data from one point to another remote sensing station. Since RF is becoming a major part of medical electronics technology, what’s emerging is specific RF testing, in addition to regular ICT, functional and flying probe. At times, an RF board cannot be probe-tested because of necessary EMI/RFI shields that limit the flying probe’s movement. As a result, an EMS provider has to rely on functional test because RF is peculiar in nature. Testing has to tune into different frequency levels at different speeds. Functional testing must be thorough and complete as a result. Obsolete Components Medical electronics OEMs are at times reluctant to make product changes simply because there’s no reason for them. The product is functioning properly; it is FDA-approved, and everything is time tested and verified. However, components often become obsolete. (This is certainly the case as component manufacturers quickly transition to Pb-free to comply with EU’s RoHS Directive.) As a result, once plentiful SnPb components are either obsolete or difficult to find, and cost a premium. An EMS provider savvy about circuitsassembly.com Special Testing Testing is specialized for medical electronics because different devices have different testing requirements. Test challenges are long and varied largely due to overwhelmingly complex FDA regulations. As a result, the demand for verification and validation is exceedingly high, and its traceability extremely critical. Figure 2 shows special testing requiring custom test fixtures. Here, product testing is for fluid viscosity applications. But in most instances, test requirements may be so challenging that a medical electronics OEM has no option other than to rely on 26 Circuits Assembly OCTOBER 2008 http://www.circuitsassembly.com

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Circuits Assembly - September 2008 Contents Letters Caveat Lector Industry News Market Watch Talking Heads Global Sourcing Screen Printing Better Manufacturing 'Checking Up' on Medical Electronics Solder Ball Attachment Using Laser Soldering Improving QFN Reliability Reflow Soldering Tech Tips Test and Inspection Process Doctor Pb-Free Lessons Learned Alternative Energies Eastern Advances Product Spotlight Ad Index Assembly Insider Technical Abstracts

Circuits Assembly - October 2008

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