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style="padding-left:10px"><!-- InstanceBeginEditable name="Article_5" --> <p align="left"><a href="manf-corner-810.html">Manufacturer&rsquo;s Corner: McDry</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_6" --> <p align="left"><a href="electronics.html">Electronics Manufacturing Boot Camp Updates</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_7" --> <a href="http://store.aciusa.org">EMTC Online Registration</a> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_8" --> <a href="../html/empfasis/emlcupcoming.pdf">Training Center Course Schedule</a> <!-- InstanceEndEditable --></td> </tr> </table> <br> <br> <hr align="center" size="1"> <br> <a href="http://store.aciusa.org"><img src="http://www.aciusa.org/images/lower-pricing-ad.gif" alt="Discount pricing on IPC training course J-STD-001, 610, 600, 7711, 7712" width="150" height="288" border="1"></a> <a href="http://www.empf.org/empfasis/subscribe.htm"> </a> <p class="style9"><script language="JavaScript"> <!-- function random_imglink(){ var myimages=new Array() myimages[1]="http://www.aciusa.org/wwwaci/html/random/boot.gif" myimages[2]="http://www.aciusa.org/wwwaci/html/random/lead.gif" myimages[3]="http://www.aciusa.org/wwwaci/html/random/help.gif" myimages[4]="http://www.aciusa.org/wwwaci/html/random/service.gif" myimages[5]="http://www.empf.org/empfasis/archive/images/subscribe2.gif" var imagelinks=new Array() imagelinks[1]="http://www.aciusa.org/courses/train_boot.htm" imagelinks[2]="http://www.empf.org/empfasis/leadfree.htm" imagelinks[3]="http://www.empf.org/helpline/helpline.htm" imagelinks[4]="http://www.aciusa.org/ana/ana_home.htm" imagelinks[5]="http://www.empf.org/empfasis/subscribe.htm" var ry=Math.floor(Math.random()*myimages.length) if (ry==0) ry=1 document.write('<a href='+'"'+imagelinks[ry]+'"'+'><img src="'+myimages[ry]+'" border=0></a>') } random_imglink() //--> </script></p> </div></td> </tr> <tr> <td colspan="2"><div align="center"><span class="style5">ACI Technologies Inc.</span><br> One International Plaza<br> Suite 600 <br> Philadelphia, PA 19113 <br> (610) 362-1200 <br> <span class="style6">FAX: </span>(610) 362-1290<br> <span class="style6">HELPLINE: </span>(610) 362-1320<br> <span class="style6">WEBSITE: </span><a href="http://www.empf.org">www.empf.org</a><br> <a href="http://www.aciusa.org">www.aciusa.org</a></div></td> </tr> </table> <p>&nbsp;</p> <p><br> <br> </p> <div align="center"> <p align="center" class="style7">Michael D. Frederickson<br> <strong><em>EMPF Director </em></strong><br> <br> Barry Thaler, PhD.<br> bthaler@aciusa.org <br> <strong><em>Empfasis Technical Editor<br> </em></strong><br> Paul Bratt<br> pbratt@aciusa.org <br> <strong><em>Empfasis Editor</em></strong><br> </p> <p align="center" class="style7"><img src="http://www.empf.org/empfasis/archive/images/iab_sm.gif" alt="IAB" width="100" height="52"><br> <span class="style9">Industrial Advisory Board</span><br> <span class="style14"><em>Gerald R. Aschoff</em>, The Boeing Company<br> <em>Dennis M. Kox</em>, Raytheon<br> <em>Gregory X. Krieger</em>, BAE Systems<br> <em>Edward A. Morris</em>, Lockheed Martin<br> <em>Jane Krueger </em>, Rockwell Collins<br> <em>Gary Kirchner</em>, Honeywell<br> <em>Andrew Paradise</em>, Northrop Grumman<br> <em>Richard Kidwell </em>, ITT Industries</span></p> </div> <p align="center" class="style7"><br> </p> </div> </td> </tr> </table> </div></td> <!-- InstanceBeginEditable name="Body1" --><td width="70%" rowspan="2" valign="top"><div class="body_style" id="body_content"> <p><img src="images/manf.gif" alt="title"></p> <p class="body_text"><span class="style20">M</span>cDry storage boxes (Figure 5-1) prevent damage (Figure 5-2) to electronic components by reducing moisture absorption into the plastic packaging. The rapid expansion of absorbed water during a high temperature reflow process causes stresses that can damage the component. If the best way to solve a problem is to prevent its occurrence, storing components in an environment with controlled temperature and humidity is the easiest and least expensive decision to eliminate the moisture absorption problem. <p align="center"><img src="images/fig5-1.gif"></p> <p align="center"><img src="images/fig5-2.gif"></p> <p>Packages of many semiconductor components are made of materials that absorb moisture (hygroscopic). When the air-tight seal is broken on a shipping package, atmospheric water vapor will be slowly absorbed by the component material. During the high temperature reflow process in the oven, rapid heating causes the absorbed water vapor in the component to expand into a hot gas which can damage the package. This damage is not always visible but it often appears as small craters called"popcorning." Since the component is mounted on the circuit board, the easily seen top of the component could be free of visible damage, but the underside and inside of the component could be damaged and not visible. The easiest way to avoid this damage is to store the components in an environment where the humidity is controlled and held to very low levels.</p> <p>McDry manufactures a line of metal storage boxes that routinely maintain a relative humidity of 5% and can offer storage down to 1%. Moisture is removed from the interior of the cabinet with a chemical desiccant system. When saturated, the desiccant is heated, releasing the trapped water through a vent to the outside of the cabinet. The vent then closes and the process repeats as needed. Recognizing that some customers and components demand almost zero humidity, the dry boxes are also available with a nitrogen purge. Flooding the cabinet with nitrogen drives out any moisture laden air much more quickly than the desiccant system (which can take as much as 15 minutes). This nitrogen purge can be exceptionally valuable when the door to the storage box is often opened and closed.</p> <p>McDry storage cabinets conform to IPC/JEDEC J-STD-033B.1,"Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices." Since space is usually at a premium on the production floor, these low humidity storage boxes are available in a variety of sizes to fit the available space in the factory.</p> <p>Recording the humidity is required in many applications to assure that the components have never been exposed to any moisture. The McDry storage boxes have an optional humidity recorder to provide records of humidity compliance.</p> <p>In conclusion, a McDry storage box provides an industry standard of moisture protection for a very modest investment. Surface mount assembly equipment is expensive. Skilled labor to assemble and test the assemblies is expensive. The components are expensive. All this investment can be jeopardized if poor handling and storage practices lead to components that are damaged due to absorbed moisture. Storage boxes are a sound and sensible investment. For more information on the McDry storage box, please contact Mike Prestoy at mprestoy@aciusa.org.</p> <p class="body_text"><img src="../../archive/updated/mprestoy.gif"></p> </div> </td> <!-- InstanceEndEditable --> </tr> <tr> </tr> </table> <br> <table width="100%" border="0"> <tr> <td colspan="2"><div align="center"> <p><em>The EMPF is a U.S. Navy-sponsored National Electronics Manufacturing Center of Excellence focused on the development,<br> application, and transfer of new electronics manufacturing technology by partnering with industry,<br> academia, and government centers and laboratories in the U.S</em></p> </div></td> </tr> <tr> <td class="footer">ACI Technologies, Inc. - - <a href="http://www.aciusa.org">www.aciusa.org</a> - - (610)362-1200</td> <td><div align="right"><a href="http://www.navymantech.com"><img src="http://www.empf.org/empfasis/archive/images/mantech.gif" width="144" height="42" border="0"></a></div></td> </tr> </table> <div align="right"> <!-- Start of StatCounter Code --> <script type="text/javascript" language="javascript"> var sc_project=350643; var sc_partition=1; </script> <script type="text/javascript" language="javascript" src="http://www.statcounter.com/counter/counter.js"></script> <noscript> <a href="http://www.statcounter.com/free_hit_counter.html" target="_blank"><img src="http://c2.statcounter.com/counter.php?sc_project=350643&amp;amp;java=0" alt="hit counter" border="0"></a> </noscript> <a href="http://www.empf.org/sitemap.htm"><em>[site map] </em></a> <!-- End of StatCounter Code --> <!-- Start of StatCounter Code --> <script type="text/javascript" language="javascript"> var sc_project=1902214; var sc_invisible=1; var sc_partition=17; var sc_security="759b802c"; </script> <script type="text/javascript" language="javascript" src="http://www.statcounter.com/counter/counter.js"></script><noscript><a href="http://www.statcounter.com/" target="_blank"><img src="http://c18.statcounter.com/counter.php?sc_project=1902214&java=0&security=759b802c&invisible=1" alt="website statistics" border="0"></a> </noscript> <!-- End of StatCounter Code --> </div> </body> <!-- InstanceEnd --></html>