I am investigating the bonding performance of PEM nuts that act to support a PCB within a housing and am looking for your insight as to how they will perform bonding wise, electrically and thermally.
* My concern is to maintain a safety and EMC bond from the PCB to the sheet metal enclosure. * Secondly I was expecting that the PEM nuts would also act as a heat sink >from the PCB but now I am questioning if this is significant or not. I have 5 BGAs that dump a lot of heat into the PCB ground plane. Details: * The 9 PEM nuts are .400" tall and take a #6 screw and are spaced around the perimeter of a ~8" square .090" thick (PCB) printed circuit board but with one in the center. * This 10 layer board has a top and bottom pour and the inner ground planes that all connect directly to the (PTH) plated through hole PEM nut mounts. * I believe the PEM nuts have a nickel plating and the PCB has a solder tined PTH. * The PEM nuts are pressed into a .040" sheet steel with either a Black or Yellow Trivalent zinc chromate plated finish (plating is still under review). * At this point the PEM nuts have a flat surface but I am looking into some alternatives that may have a "toothed" surface. * The Board is held down using conical washers. * The PCB PTH barrel is plated and the perimeter is supported by a series of 12 plated vias around each via. These vias add support to the mounting point and help reduce the compression effects that are often brought up on this PCB bonding topic Your Thoughts? Thanks Chris Wells Eaton Electrical [email protected] - work email. (if you can forward response to work that would be most helpful - IT has banned this group from my work email since they think it is SPAM) ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Scott Douglas [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
