Circuits Assembly - October 2008 - (Page 3)

Building Solar Cells Off Your SMT Line, p. 40 OCTOBER 2008 circuitsassembly.com Which Was Laser-Soldered? (Answer on page 28) OCTOBER 2008 – Vol. 19 No. 10 Solder Volume’s Effect on QFN Reliability FIRST PERSON 4 Letters 6 Caveat Lector Doing business, the standard way. Mike Buetow The Pulse of Medical Assembly Pb-Free PCB Rework FEATURES Medical Electronics Assembly ON THE COVER: A laser reballing process can cut two temperature excursions. 16 Talking Heads Design Chain Associates’ Mike Kirschner Chelsey Drysdale 24 ‘Checking Up’ on Medical Electronics Medical electronics assembly demands a different set of criteria than do commercial PCBs. The US FDA requires specific documentation, especially for verification of certain processes. Today’s medical electronics assembly also requires special testing, avoiding obsolete components and a detailed evaluation of a Pb-free product, as a looming EU RoHS Directive is expected to include medical electronics. By Zulki Khan MONEY MATTERS 17 Global Sourcing Outsourcing gets medieval. Charlie Barnhart COVER STORY 28 Solder Ball Attachment Using Laser Soldering Reballing BGAs due to rework and conversion from RoHS-compliant solders to SnPb (or vice-versa) typically requires subjecting the component to additional reflow cycles beyond component manufacturer recommendations. Laser attachment or laser reballing in an oxygen-free bath eliminates two additional temperature excursions and provides improved component reliability by facilitating the use of standard assembly reflow temperatures without mixed alloys. By Joshua Muonio and Richard Stadem TECH TALK 18 Screen Printing One size doesn’t fit all. Clive Ashmore 20 Better Manufacturing A mask for all seasons. Phil Zarrow Components 32 Improving QFN Reliability The proper amount of solder is needed to ground the bottom of a QFN package and simultaneously create a toe fillet. Too much solder on the ground plane can cause parts to float; too little means insufficient grounding. This article focuses on the toe fillet and bottom connection, which create a kind of two-pronged connector, providing electrical continuity from both points. By Joseph G. Ameen and Gilson V. Geralde 34 Reflow Soldering Optimal oven conditions. Ursula Marquez de Tino 35 Tech Tips Reworking Pb-free PCBs. American Competitiveness Institute This month at PCDandF.com Copper Erosion: The Influence of Metallurgy on Copper Dissolution The rate of copper dissolution in Pb-free soldering may be linked to the physical characteristics of the copper as well as the alloy. By Chrys Shea, Jim Kenny, Jean Rasmussen, Girish Wable, Quyen Chu, Shiang Teng, Keith Sweatman and Dr. Kazuhiro Nogita 36 Test and Inspection ICT gets probed. Stacy Kalisz Johnson 38 Process Doctor Cleaning becomes an event. Michael Bixenman 39 Pb-Free Lessons Learned The tenacity of Pb-free residues. Chrys Shea The Wave of the Future Not all PCB manufacturing orders are coming back to the US, but increasing offshore costs are giving rise to fundamental changes in global outsourcing strategies. By Greg Papandrew 40 Alternative Energies Adding solar cells to the SMT line. Darren Brown 42 Eastern Advances Soldering terminations. Sanqiang Cai 48 Technical Abstracts DEPARTMENTS 8 Industry News 14 Market Watch 44 Product Spotlight 46 Ad Index 47 Assembly Insider Photos courtesy General Dynamics http://www.PCDandF.com

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

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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